Month: March 2019

On grapevine adaptation to drought: new insights into the genotype-dependent responses to water stress

By Cardone Maria Francesca, Catacchio Claudia Rita, Alagna Fiammetta, Ventura Mario

Climate change can affect grapevine phenology, grape composition, production, and consequently the suitability for cultivation in whole territories. Among the parameters linked to climate change, there is the water availability, which becomes increasingly limited and affects the quantity and quality of the production all over the world (Casassa, et al. 2013; Casassa, Keller, and Harbertson 2015). Many vineyards, especially those devoted to table grape production, are located in areas, such as Mediterranean regions, California, Chile, and many others, often affected by severe water deficit. Thus, in order to promote a more sustainable viticulture, a reduction of water use has become essential. This is the challenge driving the recent researches to identify tolerant varieties with a better adaptation to water deficit.
Vitis vinifera L. has been described as relatively tolerant to water deficit. At the physiological level, stomata closure is one of the first responses to water deficit, in order to prevent the hydraulic failure (Charrier, et al. 2018). Notably, recent researches established the genotypic-specific response of grapevine to drought (Dal Santo, et al. 2016). Inter-varietal differences and a dynamic physiological response to water availability have been described, thus revealing a different adaptation of grapevine varieties to the environmental conditions and a different ability to respond to water stress (Charrier, et al. 2018).
At the molecular level, the phytohormone abscisic acid (ABA) plays a key role in mediating the stomatal responsiveness to water deficit (WD). Indeed, the signal transduction cascade triggered by ABA, and involving ABA-induced gene expression, eventually leads to stomatal closure and water retention (Kim, et al. 2010; Hubbard, et al. 2010).
In our recent paper Catacchio et al. Sci Rep. 2019 Feb 26;9(1):2809 we tested the physiological and molecular responses to WD of two different table grape cultivars, Italia (It) and Autumn Royal (AR), and we highlighted their different adaptation to drought stress conditions. We, tested the effects of a reduced irrigation directly on the field in order to investigate how the mentioned different ability reflects an adaptation of the cultivars to the growing conditions. Physiological analyses on field-grown plants showed cultivar-specific variations in photosynthetic carbon assimilation, stomatal conductance and intercellular CO2 concentration under water deficiency (Figure 1).

 

 

 

Figure 1. Plants of AR and It were subjected to two different irrigation treatments from fruit set until the harvest: control FI and WD corresponding to 100% and 60% of the net irrigation requirements, respectively. For the It cultivar, an additional point of over-irrigation (OI) was tested, corresponding to an increment of 50% of water supply with respect to FI. Excess of irrigation is often practiced for table grape production; therefore, a condition of OI was also tested for cultivar It. As expected, the ψleaf showed higher levels than in the FI. Evolution of leaf water potential (Yleaf) in It and AR during the entire seasonal irrigation. Arrows indicate sampling date for gene expression assays. Sampling was performed when Yleaf revealed water deficit stress. WD: water deficit; FI: full irrigation; OI: over-irrigation. Data are means ± S.D. *denotes significant (p < 0.01) difference from FI condition, as assessed by t test. All parameters showed a decline in the thesis with reduced water intake and an increase of the intrinsic water use thus confirming the stress status in both cultivars. The comparison of the physiological overall data suggested that WD treatment resulted in better intrinsic water use efficiency in AR with respect to It.

We further used a combined approach based on “omic” analyses by integrating transcriptomic and genomic data to identify candidate genes involved in drought stress response and adaptative traits. With respect to previous data(Dal Santo, et al. 2016; Grimplet, et al. 2009; Cramer, et al. 2007; Cramer, et al. 2011; Rocheta, et al. 2016), we focused our attention on the early response to WD. In agreement with the genotype-dependent response, our microarray analyses revealed a broad response of cultivar It to drought stress conditions characterized by the modulation of more than 1000 genes involved in biological processes as cell wall organization, carbohydrate metabolism, response to reactive oxygen species (ROS), response to hormone and osmotic stress. On the contrary, AR response was limited to the modulation of only 29 genes mainly involved in plant stress response, nitrogen metabolism and hormone signal transduction. We assumed that AR showed a limited and specific response, involving the modulation of genes specifically related to plant defense mechanisms, including drought-responsive genes such as desiccation proteins. Moreover, the strong differences observed between AR and It under WD stress might also depend on a different timing of response between the two cultivars: AR could activate later a more extensive response to WD. This suggests that the genotype-specific responses to WD need to be investigated at the early phases after WD onset. This behaviour could probably reflect a better adaptation of AR to WD conditions. Indeed, adaptation and resilience to water stress, such as the extremely limited response in the early phase found in AR, could be considered more advantageous. In this way, the plant could activate its defense responses more gradually - only if the WD condition is prolonged - and this could avoid investing much resources and energy if not strictly necessary (Figure 2).

 

Figure 2. Identification of genes differentially expressed under water deficit in table grape varieties It and AR. (a) Hierarchical Clustering Analysis (HCA) of DEGs. Colors indicate transcriptional activation (red) or repression (yellow). The columns and rows represent samples and genes, respectively, that were grouped based on their expression profile. (b) Principal Component Analysis (PCA) depicting global gene expression profile of AR and It at different water conditions. The analysis highlights that variation between cultivars is higher than between conditions. (c) Venn diagrams show down- and up-regulated genes between different water conditions. The comparison between OI and FI in It does not reveal any significant DEGs. Italia significantly modulated a total of 1037 genes (316 up- and 721 down-regulated), whereas AR, despite an overall variation of expression profile, showed only 29 DEGs between FI and WD (21 up- and 8 down-regulated). Noteworthy, 20 of these genes were common to It responses, whereas, nine genes were modulated exclusively in this cultivar. (d) Venn diagrams show down- and up-regulated genes in AR compared to It. The higher variation of gene expression between cultivars is depicted at WD (the number of DEG is underlined). AR: Autumn royal; IT: Italia; WD: water deficit; FI: full irrigation; OI: over-irrigation.

Besides differences in experimental settings, pedo-climatic and growing conditions, other than tissues analysed, our data confirmed what found in previous studies, revealing the importance of such pathways in the response to water stress: WD induces modulation in genes related to response to stimuli, response to abiotic stress, ABA response, protein and carbohydrate metabolisms, nitrogen metabolism, and ROS response. Notably, both the analysed varieties showed modulation of genes related to osmotic stress response and those related to the primary immune plant system such as the defense proteins (PR1) (Figure 3).

 

Figure 3. Network analysis of genes differentially expressed under water deficit in table grape cultivars It and AR. (a,b) Network of genes differentially expressed under WD in cultivars It and AR, respectively. For cv. It only terms containing at least three genes were shown, this restriction was not applied for cv. AR. Nodes with up- or down-regulated genes are shown in red or green, respectively. (c,d) Network of genes differentially expressed between cvs. It and AR at water deficit condition (WD) and regulated under water stress, as indicated by Venn Diagrams. Yellow- and blue-circled numbers represent, respectively, selected down- and up-regulated genes between AR vs It. Nodes with up- or down-regulated genes (AR was used as reference) are shown in blue or yellow, respectively. Data are visualized as clusters distribution network (Cytoscape, ClueGO App). Only significant (p < 0,005) terms belonging to GO biological process and Kegg ontologies were shown. The node size is proportional to the term significance. The colour gradient shows the proportion of up- and down-regulated genes associated with the term. Equal proportions of both clusters are represented in gray. AR: Autumn royal; IT: Italia; WD: water deficit; DEG: differentially expressed genes.

In order to understand the molecular basis of such kind of genotypic-specific response, we deeply analyzed NGS data belonging to the studied cultivars and we identified structural variants in stress-related genes. Many genomic variations were also correlated to the expression differences, and thus putatively associated to the different genotypic-specific behaviour observed in response to WD. Indeed, we focused our attention on copy number variant (CNV) regions and single nucleotide variants (SNVs) affecting gene transcription. By looking at the annotated polymorphisms for each cultivar (Cardone, et al. 2016), we found 159 CNVs and 336 SNVs overlapping with genes differentially expressed between AR and It under WD. Among these, we selected 23 CNVs and 25 SNVs occurring in genes differentially expressed between AR and It as candidate genes for the genotype-dependent response to drought. Our data highlighted that ABA perception and signalling are key factors mediating the varietal-specific behavior of the early response to drought. A hypothetical scheme of the ABA-mediated mechanisms involved in responses to WD stress in cultivars AR and It is depicted in Figure 4.

 

Figure 4. ABA-mediated response to drought stress in cvs. It vs AR. The ABA-responsive transcription factors (TF) belonging to AP2-EREB family: ERF5 (VIT_16s0013g00980, VIT_16s0013g00990, VIT_16s0013g00950, VIT_16s0013g01060, VIT_16s0013g01050, VIT_16s0013g01030), DREB1A (VIT_16s0100g00380) and DDF2 (VIT_02s0025g04460) are down-regulated under WD in It, whereas, ERF (VIT_09s0002g09120), ABF2 (VIT_18s0001g10450), MYB102 (VIT_19s0014g03820), the homeobox-leucin zipper protein HB-12 (VIT_16s0098g01170) and the zing-finger protein STZ (VIT_03s0091g00690) are up-regulated. ERFb (VIT_09s0002g09140) is the only TF differentially expressed in both AR and It at WD. TF might regulate the expression of drought related genes, for instance, the down-regulation of desiccation protein PCC13-62 VIT_07s0005g00080), DRS1 (VIT_11s0149g00190), MPK4 (VIT_15s0046g02000), ERD7 (VIT_03s0038g02290), HVA22F (VIT_12s0142g00440) and the upregulation of RD22 (VIT_04s0008g03930), RD26 (VIT_19s0014g03290), XERICO (VIT_12s0057g01330), GEA6 (VIT_13s0067g01240, VIT_13s0067g01250), ABI1 (VIT_11s0016g03180). ABI1 proteins might act in a negative feedback regulatory loop of ABA. The table compares copy number variation (CNVs) and RNA expression of ABA-responsive genes. + indicates higher number of CNVs or mRNA expression in It compared to AR. The ABA-responsive genes HVA22A (VIT_03s0132g00070, VIT_03s0132g00080) and RD22 showed higher CNs in It compared to AR, according to their higher expression in It, whereas GTG2 (VIT_07s0005g06120) and ABI1 showed higher CNs in It but did not resulted differentially expressed between cultivars. Genes whose promoters contain ABRE or ABRE-related motifs are underlined. In parentheses it is indicated the number of genes.

 

Our results suggest that the increase of ABA and/or of ABA perception in cultivar It could be responsible for the transcriptional induction/repression of signalling genes and transcription factors, such as those belonging to AP2/AREB and MYB families. They might affect the transcriptional regulation of drought-related genes. In contrast to the 25 ABA-responsive genes differentially expressed in It in response to WD, only two genes resulted differentially expressed in AR highlighting that ABA perception is strongly genotype-dependent. These insights will allow the identification of reliable plant stress indicators and the definition of sustainable cultivar-specific protocols for water management.
Those interested in a longer length report can download the working paper at:
https://www.nature.com/articles/s41598-019-39010-x

 

 

Dr. Maria Francesca Cardone was born in Italy, Cerignola (FG), the 7th November 1977. In 2001 she graduated with honors in Biological Sciences at the University of Bari. In November 2001 she qualified to the free profession of biologist then she started the PhD in "Molecular Genetics and Evolution" at the Department of Genetics and Microbiology, University of Bari, and she achieved the title in March 2005. During her PhD she worked in the United States of America at the Children's Hospital Oakland Research Institute (CHORI) in California. Her PhD thesis won FISV 2006. From 2005 to 2008 attended the School of Specialization in Medical Genetics at the University of Chieti "G. D'Annunzio" and she achieved the title with honors in December 2008. In 2009 she won the prize "Citta 'di Ponzano Romano for Science 2009" for excellent young researchers. From 2005 to 2010 she also carried out research and teaching activities in genetics and structural genomics at the University of Bari with research grants and work contracts. In March 2010, she won the public competition research at the Council for Agricultural Research and Economics - Research Centre for Viticulture and Enology in Turi (BA) and she began working on the topics of molecular characterization and genotyping of grapevine germplasm, study of genetic variability, genomics and transcriptomics of grapevine, molecular breeding, MAS, development of molecular tools for genetic improvement of conventional and unconventional vines, next generation breeding. She was hired permanently, in December 28, 2012 and since then she is actively involved as PI or partner in several projects and scientific collaborations aiming to understand the molecular bases of the most important and studied traits for the molecular breeding of table grapes, and to favor the implementation of biotechnology and omics methods for genetic improvement in Vitis vinifera. Dr. Cardone is author of more than 70 scientific publications mostly on international journals – ISI (h-Index =19).

Dr. Claudia Rita Catacchio was born in Bari, Italy, on the 20th June 1984. She has a master degree with honors in Medical Biotechnologies (2007) and doctoral degree in Genetics and Evolutionary Biology (2012). Her research experience includes working as visiting scientist at the Edinburgh Cancer Research Center (Edinburgh, UK) in 2008, at the Department of Genome sciences (Seattle, WA) in 2009-2010 and at the European Molecular Biology Laboratory (Heidelberg, Germany) in 2017. Her scientific production is mainly dedicated to the study of genomic structural variations and the evolution of animal and plant genomes, with a particular focus on primate genomes. In 2015 she had a research assistant fellowship funded by the “Agenzia regionale per la tecnologia e l’innovazione” to study the intervarietal genomic differences in grape genomes. She is author of numerous articles, with papers in top-ranking scientific journals, and collaborates with top molecular biology labs, both in Europe and in the United States. In December 2018 she got a position as Assistant Professor at the Department of Biology (University of Bari).

Dr. Fiammetta Alagna is currently Researcher at ENEA, Italian National Agency for New Technologies Energy and Sustainable Economic Development, Trisaia Research Centre (Italy). She graduated in plant biotechnology at University of Naples “Federico II” in 2004. At the same University, in 2006, she attained a Master in “Biotechnology applied to feed quality and safety”. In 2010 she graduated with a PhD in “Insect Science and Biotechnology” from University of Basilicata. Since 2005, she performed her research activities working in different research institutions, including the CNR – IBBR in Portici and Perugia (Italy), the University of Naples Federico II (Italy), the Max Plank Institute of Chemical Ecology in Jena (Germany), the John Innes Centre in Norwich (United Kingdom), the Research Centre for Viticulture and Enology of CREA in Turi (Italy) and the ENEA. Alagna’s research activity is focused on plant molecular biology, functional genetics and transcriptomics. She mainly worked on tree plants (olive and grapevine) focusing on the identification and functional characterization of genes involved in plant natural products biosynthesis (e.g. terpenes and phenolics), plant defence responses and reproductive barriers. She is author of more than 90 publications, 22 on ISI journals with impact factor.

Professor Mario Ventura born in Taranto in 11/10/1975 and studied at University of Bari where he got his PhD title the 7th of March 2003 discussing a thesis on “Human Genome plasticity: Pericentromeric regions and Neocentromeres”. He became Assistant professor at University of Bari in the 2007 where he started his independent group and research. He worked one year at at the Newcastle University (UK) in the Human Genetics Laboratory, supervisor M.S. Jackson studying the chromosome 10 pericentromeric region in baboon. He got EMBO Short term fellowship for the project “Evolution of pericentromeric regions and their plasticity” performed at the Newcastle University and a Fulbright Research Scholarship for the research project “Human Genome Structural Variation and Genetic Disease” carried out at the University of Washington- Seattle. Main focus and interests at the moment are: centromeric and pericentromeric regions in human and primates and primates and mammals and plant genome organization. Prof. Ventura published 97 papers in medium-high impact factor journals (h-index 41) and 5 chapters in books on genomics.

References:

Cardone, M. F., et al. 2016. "Inter-Varietal Structural Variation in Grapevine Genomes." Plant J  (Jul). http://dx.doi.org/10.1111/tpj.13274.

Casassa, L. F., M. Keller, and J. F. Harbertson. 2015. "Regulated Deficit Irrigation Alters Anthocyanins, Tannins and Sensory Properties of Cabernet Sauvignon Grapes and Wines." Molecules 20, no. 5 (Apr): 7820-44. http://dx.doi.org/10.3390/molecules20057820.

Casassa, L. F., et al. 2013. "Impact of Extended Maceration and Regulated Deficit Irrigation (Rdi) in Cabernet Sauvignon Wines: Characterization of Proanthocyanidin Distribution, Anthocyanin Extraction, and Chromatic Properties." J Agric Food Chem 61, no. 26 (Jul): 6446-57. http://dx.doi.org/10.1021/jf400733u.

Charrier, G., et al. 2018. "Drought Will Not Leave Your Glass Empty: Low Risk of Hydraulic Failure Revealed by Long-Term Drought Observations in World's Top Wine Regions." Sci Adv 4, no. 1 (Jan): eaao6969. http://dx.doi.org/10.1126/sciadv.aao6969.

Cramer, G. R., et al. 2007. "Water and Salinity Stress in Grapevines: Early and Late Changes in Transcript and Metabolite Profiles." Funct Integr Genomics 7, no. 2 (Apr): 111-34. http://dx.doi.org/10.1007/s10142-006-0039-y.

---. 2011. "Effects of Abiotic Stress on Plants: A Systems Biology Perspective." BMC Plant Biol 11: 163. http://dx.doi.org/10.1186/1471-2229-11-163.

Dal Santo, S., et al. 2016. "Distinct Transcriptome Responses to Water Limitation in Isohydric and Anisohydric Grapevine Cultivars." BMC Genomics 17, no. 1 (10): 815. http://dx.doi.org/10.1186/s12864-016-3136-x.

Grimplet, J., et al. 2009. "Proteomic and Selected Metabolite Analysis of Grape Berry Tissues under Well-Watered and Water-Deficit Stress Conditions." Proteomics 9, no. 9 (May): 2503-28. http://dx.doi.org/10.1002/pmic.200800158.

Hubbard, K. E., et al. 2010. "Early Abscisic Acid Signal Transduction Mechanisms: Newly Discovered Components and Newly Emerging Questions." Genes Dev 24, no. 16 (Aug): 1695-708. http://dx.doi.org/10.1101/gad.1953910.

Kim, T. H., et al. 2010. "Guard Cell Signal Transduction Network: Advances in Understanding Abscisic Acid, Co2, and Ca2+ Signaling." Annu Rev Plant Biol 61: 561-91. http://dx.doi.org/10.1146/annurev-arplant-042809-112226.

Rocheta, M., et al. 2016. "Transcriptomic Comparison between Two Vitis Vinifera L. Varieties (Trincadeira and Touriga Nacional) in Abiotic Stress Conditions." BMC Plant Biol 16, no. 1 (10): 224. http://dx.doi.org/10.1186/s12870-016-0911-4.

 

Posted by in Viticulture

On the use of Micro-NIRS technology to evaluate wine extractable total phenolic and ellagitannin contents in revalorized cooperage byproducts: a feasibility study.

By Berta Baca-Bocanegra, Julio Nogales-Bueno, Ignacio García-Estévez, María Teresa Escribano-Bailón, José Miguel Hernández-Hierro and Francisco José Heredia

The addition of commercial oak wood (Del Álamo, Nevares, Gallego, Martin, & Merino, 2008; Nevares, Del Alamo, Cárcel, Crespo, Martin, & Gallego, 2008) or wood compounds (Balík, Híc, Kulichová, Novotná, Tříska, Vrchotová, et al., 2017) has been aimed at implementing the production of high quality red wines in the last years. During the contact time, different types of oak compounds are released from the wood to the wine, thus affecting its organoleptic properties such as aroma, color or astringency. Among these compounds, ellagitannins, with several hydroxyl groups, can take part in oxidation reactions (García-Estévez, Alcalde-Eon, Martínez-Gil, Rivas-Gonzalo, Teresa Escribano-Bailón, Nevares, et al., 2017; Vivas & Glories, 1996) that may favor the polymerization reactions between flavanols and between flavanols and anthocyanins. Wood processing for the elaboration of barrels generates by-products that seem to be an interesting product in the oenological field due to its potential capacity of releasing high added-value compounds for wine. Predicting phenolic compounds of wood by-products and its extractability from the matrix to the hydroalcoholic medium could be important in the oenological industry.
Vibrational spectroscopy techniques represent emerging analytical procedure, which is enjoying increasing popularity in the industry as non-destructive, environmental friendly and rapid technique. A new generation of portable/handheld NIR spectrometers (Figure 1) have been developed within the last years. These systems incorporate the analytical precision for chemical identification and quantitation with a spectral resolution equivalent to bench-top instruments, allowing for flexibility for in-plant analysis since the unit can be easily carried and transferred. In the agro-food industry, the potential of this technique has been highlighted for assessing the quality of fruits nondestructively in the field under different weather conditions (Abu Izneid, Fadhel, Al-Kharazi, Ali, & Miloud, 2014; Antonucci, Pallottino, Paglia, Palma, D'Aquino, & Menesatti, 2011; Camps, Simone, & Gilli, 2012).

 

 

 

Figure 1. The used portable micro NIR spectroscopy device (Micro-NIR Pro Lite 1700 device (VIAVI, Santa Rosa, California, USA)).

To carry out this study, American non-toasted oak (Quercus alba L.) shavings, cooperage byproduct, provided by Toneleria Salas S.L. were used. In order to achieve representative sample sets, the samples were taken at 4 different points of the barrel manufacturing process were chosen: automatic sawing of the staves (A), manual sawing of the staves (B), shaving of the staves (C) and shaving the edges of the barrels (D). Samples were collected periodically, between June of 2015 and January of 2016. Two hundred samples were collected during the aforesaid period. Sample selection was made in order to reduce the number of samples maintaining as much spectral variety as possible. After that, a like-wine model solution was used for the simulated maceration procedure (Figure 2).

 

 

Figure 2. Graphical description of sample selection and calibration process.

Using the raw spectral data, applying spectral pretreatments and allocating the corresponding extractable total phenolic content and extractable ellagitannin content to each sample, calibrations were performed by modified partial least squares regression (MPLS). Quantitative calibrations were developed by modified partial least squares (MPLS) regression. Extractable total phenolic content and extractable ellagitannin content were used as dependent (Y) variables and the matrix of 18 wood processed spectra was used as the independent (X). The obtained models present an adequate accuracy to determine the extractable content of total phenols and ellagitannins (as individual extractable castalagin, vescalagin, grandinin, and roburin E or total extractable ellagitannins).
The aforesaid models were used to predict the extractable content of total phenols and total ellagitannins in the whole of the wood set. The results show that both extractable phenolic content and extractable ellagitannin content describe a similar to Gaussian bell-shaped distribution for longitudinal and transversal wood sample sets (Figure 3).

 

 

 

Figure 3. Distribution of longitudinal and transversal wood samples in different extractable phenolic content (a and c) and extractable ellagitannin content (b and d). Taken from (Baca-Bocanegra, Nogales-Bueno, García-Estévez, Escribano-Bailón, Hernández-Hierro, & Heredia, 2019).

The obtained results confirmed that spectral analysis developed from Micro-NIRS could be used as a technique for in situ routine screening of the extractable polyphenolic compounds in wood cooperage byproduct. This methodology was able to predict, in situ, the extractable polyphenolic content of a sample based on spectral features as the predictor variables. The obtained results are comparable with those obtained using other bench-top devices and present the advantage of its eventual friendly use out of lab (Baca-Bocanegra, Nogales-Bueno, Hernández-Hierro, & Heredia, 2018). The use of a portable micro-spectrometer implies very interesting features since at a lower cost objective and instantaneous spectroscopic measurements can be carried out in situ with the advantage of its portability, due to its small size.

 

 

 

Berta Baca-Bocanegra, Julio Nogales-Bueno, José Miguel Hernández-Hierro and Francisco José Heredia. The Food Colour and Quality research group (Universidad de Sevilla, Spain) investigates on different areas related to the quality of food and the control of the production. Among these research areas, we can highlight the development and application of rapid quality control methodologies, especially Tristimulus Colorimetry, and the relationships between colour, chemical composition and visual assessment of several food products such as wines and grapes, citric juices, red fruits, olive oil, honey, etc. Within this research group, the spectroscopy section develops different studies for the control of food quality by means of several spectral tools.

Ignacio García-Estévez and María Teresa Escribano-Bailón. Grupo de Investigación en Polifenoles (GIP) - Department of Analytical Chemistry, Nutrition and Food Sciences - University of Salamanca (USAL), Salamanca projects are focused on the study of the role of phenolic compounds on quality and stability of food products. The main research topic is related to the impact of the phenolic maturity of red grapes on sensory quality of red wines, namely on color and astringency properties. Recent works aimed to go deepen on the study of the mechanism for astringency development through the use of physical-chemical studies, in order to provide the wine industry (both wineries and oenological industries) with basic knowledge about this complex sensation. Furthermore, our studies are also related to the analysis and characterization of phenolic composition (mainly flavonoids and phenolic acids) of different food and plant matrices.

References:

Abu Izneid, B., Fadhel, M. I., Al-Kharazi, T., Ali, M., & Miloud, S. (2014). Design and develop a nondestructive infrared spectroscopy instrument for assessment of mango (Mangifera indica) quality. Journal of Food Science and Technology-Mysore, 51(11), 3244-3252.

Antonucci, F., Pallottino, F., Paglia, G., Palma, A., D'Aquino, S., & Menesatti, P. (2011). Non-destructive Estimation of Mandarin Maturity Status Through Portable VIS-NIR Spectrophotometer. Food and Bioprocess Technology, 4(5), 809-813.

Baca-Bocanegra, B., Nogales-Bueno, J., García-Estévez, I., Escribano-Bailón, M. T., Hernández-Hierro, J. M., & Heredia, F. J. (2019). Screening of Wine Extractable Total Phenolic and Ellagitannin Contents in Revalorized Cooperage By-products: Evaluation by Micro-NIRS Technology. Food and Bioprocess Technology, 12(3), 477-485.

Baca-Bocanegra, B., Nogales-Bueno, J., Hernández-Hierro, J. M., & Heredia, F. J. (2018). Evaluation of extractable polyphenols released to wine from cooperage byproduct by near infrared hyperspectral imaging. Food Chemistry, 244, 206-212.

Balík, J., Híc, P., Kulichová, J., Novotná, P., Tříska, J., Vrchotová, N., Strohalm, J., Lefnerová, D., & Houška, M. (2017). Musts with Increased Lignan Content Through Addition of Lignan Extracts. Food and Bioprocess Technology, 10(7), 1367-1373.

Camps, C., Simone, C., & Gilli, C. (2012). Assessment of Tomato Quality Using Portable NIR Spectroscopy and PLSR with Wavelengths Selection. Acta Horticulturae, 936, 437-442.

Del Álamo, M., Nevares, I., Gallego, L., Martin, C., & Merino, S. (2008). Aging markers from bottled red wine aged with chips, staves and barrels. Anal Chim Acta, 621(1), 86-99.

García-Estévez, I., Alcalde-Eon, C., Martínez-Gil, A. M., Rivas-Gonzalo, J. C., Teresa Escribano-Bailón, M., Nevares, I., & del Alamo-Sanza, M. (2017). An Approach to the Study of the Interactions between Ellagitannins and Oxygen during Oak Wood Aging. Journal of Agricultural and Food Chemistry, 65(31), 6369-6378.

Nevares, I., Del Alamo, M., Cárcel, L. M., Crespo, R., Martin, C., & Gallego, L. (2008). Measure the Dissolved Oxygen Consumed by Red Wines in Aging Tanks. Food and Bioprocess Technology, 2(3), 328-336.

Vivas, N., & Glories, Y. (1996). Role of oak wood ellagitannins in the oxidation process of red wines during aging. American Journal of Enology and Viticulture, 47(1), 103-107.

 

Posted by in Enology

Aging of Aglianico and Sangiovese wine on mannoproteins: effect on astringency and colour

By Alessandra Rinaldi

Mannoproteins (Mps) are naturally present in wine, because they are integral constituents of yeast cell wall. In winemaking conditions Mps are released by Saccharomyces cerevisiae during two phases of yeast cell cycle: 1) during alcoholic fermentation when cells are actively growing; and 2) during autolysis when cells are dying. The release of these compounds during wine aging on lees contributes to the organoleptic and physicochemical properties of wines. During the last years different commercial preparations based on yeast derivatives have been used in order to replace traditional ageing on lees, and actually are authorized by the International Organisation of Vine and Wine (Oeno 26/2004). Besides white wines, mannoproteins showed beneficial effects also on red wines, contributing to colour stability, to tasting improvements and flavor complexity (Pozo-Bayón, Andújar-Ortiz, & Moreno-Arribas, 2009). In this work, three commercial mannoproteins (MP; MF; MS) were tested in Aglianico and Sangiovese red wine during one year of aging to evaluate the influence on astringency characteristics (astringency intensity and 16 subqualities), and colour parameters (CIE L*a*b* coordinates, total anthocyanins, pigmented polymers) after 3, 6 and 12 months. The taste, odor and aroma profiles completed the sensory evaluation of one-year aged wines.
Aglianico wine is well known to be a wine rich in tannins, and highly astringent (Rinaldi, Iturmendi, Jourdes, Teissedre & Moio, 2015). Astringency intensity of Aglianico after 12 months, decreased in a significant way with MP treatment. A positive effect of Mps in reducing astringency was also previously stated (Rinaldi, Gambuti & Moio, 2012a), probably the interaction with phenolic compounds could prevent aggregation or precipitation of tannins. The qualitative aspect of astringency was evaluated by the use of the CATA question by a jury trained for astringency subqualities as previously reported (Rinaldi & Moio, 2018). Until now the effect of Mps on the subqualitative profile of astringency in red wines has never been studied.

 

 

Figure 1. Correspondence Analysis performed on the mean of citation frequencies of the astringency subqualities included in the Check-All-That-Apply (CATA) question for Aglianico wine not treated (t=0; C-3,C-6, C-12), and aged with MS, MF, and MP mannoproteins for 3, 6, and 12 months.

In Figure 1, the correspondence analyses (CA) reveals that in tannin-rich wine as Aglianico the treatments with MP and MF were effective in reducing negative subqualities during aging (from 6 to 12 months), providing different sensory results. MP had an effect in removing the green and aggressive character of tannins making the wine silk, soft and full-bodied, while MF contributed to aroma complexity (rich and persistent) together with velvety and mouthcoating sensations.
In Sangiovese no differences in astringency were perceived after 12 months of aging. However, the effect of Mps was to reduce a strong astringency associated to sourness (green) and bitterness (hard), and to reach velvet, full-body, soft, rich and persistent sensations independently from the typology of Mps. The MF resulted the treatment that accelerated the achievement of such positive subqualities of astringency after 3 months of aging (Figure 2).

 

 

Figure 2. Correspondence Analysis performed on the mean of citation frequencies of the astringency subqualities included in the Check-All-That-Apply (CATA) question for Sangiovese wine not treated (t=0; C-3,C-6, C-12), and aged with MS, MF, and MP mannoproteins for 3, 6, and 12 months.

An aging period of 12 months with Mps affected the overall flavor profile of Aglianico depending on the commercial preparation used (Figure 3).

 

 

Figure 3. Sensory profile (-OD: odor; -AR: aroma) of Aglianico wine after 12 months of aging with MS, MF, and MP mannoproteins.

The effect of MF on taste was to reduce the sour sensation of Aglianico. This was in accordance with the proposed benefits of MF, a highly purified product with a high content of mannoproteins, that is to increase the perception of volume, roundness and length on the palate. In addition, the high protein content has been shown to be mainly related with an increase of flavor intensity, body balance and persistence (Ribeiro, Fernandes, Nunes, Filipe-Ribeiro & Cosme, 2014). All treatments in Aglianico significantly decreased the herbaceous aroma respect to control wine. The MS enhanced the floral aroma, mainly associated to violet (Cf > 20%), and together with MF enhanced the spicy one related to black pepper. As regard the odor, the black pepper was enhanced in MP treated wine while the balsamic notes increased both in MP and MF. As concern Sangiovese wine, the MP treatment was highly effective in decreasing the bitter perception, and increased the fruity aroma related to red cherry (Figure 4).

 

 

Figure 4. Sensory profile (-OD: odor; -AR: aroma) of Sangiovese wine after 12 months of aging with MS, MF, and MP mannoproteins.

The floral aroma (rose) was significantly enhanced by MP and MF. Similarly, the presence of polysaccharides in wines had showed an effect on the intensities of the floral aroma attributes (Jones, Gawel, Francis & Waters, 2008). The herbaceous odor decreased by means of all Mps, indicating that a “fining effect” was obtained on these molecules negative for appreciation.
As regard colour, at the 6th month of Aglianico aging, the treatments with MS and MF promoted significant pigmented polymers (SPP+LPP) formation respect to control. However, no significant differences were denoted between samples after 1 year of aging. Probably the mannoproteins accelerated pigmented polymers formation by favoring multiple interactions with anthocyanins and flavanols which necessitates additional six months in untreated wines. The effect on the stabilization of the coloring matter by mannoproteins was recently observed, due to an increase in anthocyanin-derived pigments (A-type vitisins and F-A+ dimers) (Alcalde-Eon et al., 2014).
In Sangiovese wine the formation of pigmented polymers was enhanced in MS-6 and MF-6, and then at 12 months by all treatments. These Mps favored the formation of pigmented polymers with anthocyanins resistant to the action of SO2 as observed by others (Del Barrio-Galán, Pérez-Magariño, Ortega-Heras, Guadalupe, & Ayestarán, 2012), thus enhancing the colour stability of Sangiovese wine.
Results were in accordance with many studies on the beneficial effect of mannoproteins on astringency, sensory properties and colour stability. An improvement of the mouthfeel sensations was obtained depending on aging period and Mps typology. Commercial mannoproteins improved the sensorial characteristics related to body and persistence of wine, while not treated wines remained astringent, hard and characterized by green tannins. Finally, mannoproteins may have a positive effect on sensory perception of red wine, reducing astringency and bitterness, and encouraging aroma revelation and odor complexity. As regard the effect on colour, commercial preparations were mostly effective on Sangiovese wine, characterized by low colorant intensity and high hue values, promoting the pigmented polymer formation, and thus contributing to a better stability of wine colour during time.

Those interested in a longer length report can download the working paper at:
https://www.sciencedirect.com/science/article/pii/S0023643819301240

 

 

 

 

Alessandra Rinaldi

Alessandra Rinaldi actually is a researcher employed by Biolaffort, a research and development section of the enological society Laffort (Bordeaux, France) and detached at the University of Naples Federico II (Avellino, Italy). She received her master’s degree in Industrial Biotechnology from the University of Naples Federico II (2002) and attended the Laboratory of Enology of Bordeaux University directed by prof. Denis Dubordieu. She received the doctorat degree (funded by Biolaffort) in Science and Technology of Food-Agriculture Production from the University of Naples Federico II (2013) and attendend the Laboratory of Chemistry at ISVV (Bordeaux University) directed by prof. Pierre-Loius Teissedre. She has been working on yeast fermentation, on molecular microbiology, on wine technology, and on astringency sensation of red wines. During the last years she developped an analitical method to assess grape and wine astringency. She received a post-doctorat research bourse funded by Biolaffort on the enological potentiality of a protein extracted from potatoes for must and wine fining.

References:

Alcalde-Eon, C., García-Estévez, I., Puente, V., Rivas-Gonzalo, J. C., & Escribano-Bailón, M. T. (2014). Color stabilization of red wines. A chemical and colloidal approach. Journal of Agricultural and Food Chemistry, 62(29), 6984-6994.

Del Barrio-Galán, R., Pérez-Magariño, S., Ortega-Heras, M., Guadalupe, Z., & Ayestarán, B. (2012). Polysaccharide characterization of commercial dry yeast preparations and their effect on white and red wine composition. LWT-Food Science and Technology, 48(2), 215-223.

Jones, P. R., Gawel, R., Francis, I. L., & Waters, E. J. (2008). The influence of interactions between major white wine components on the aroma, flavour and texture of model white wine. Food Quality and Preference, 19(6), 596-607.

Pozo-Bayón, M. Á., Andújar-Ortiz, I., & Moreno-Arribas, M. V. (2009). Scientific evidences beyond the application of inactive dry yeast preparations in winemaking. Food Research International, 42(7), 754-761.

Ribeiro, T., Fernandes, C., Nunes, F. M., Filipe-Ribeiro, L., & Cosme, F. (2014). Influence of the structural features of commercial mannoproteins in white wine protein stabilization and chemical and sensory properties. Food Chemistry, 159, 47-54.

Rinaldi, A., & Moio, L. (2018). Effect of enological tannin addition on astringency subqualities and phenolic content of red wines. Journal of Sensory Studies, 33(3), e12325.

Rinaldi, A., Gambuti, A., & Moio, L. (2012a). Precipitation of salivary proteins after the interaction with wine: the effect of ethanol, pH, fructose, and mannoproteins. Journal of Food Science, 77(4), C485-C490.

Rinaldi, A., Iturmendi, N., Jourdes, M., Teissedre, P. L., & Moio, L. (2015). Transfer of tannin characteristics from grape skins or seeds to wine-like solutions and their impact on potential astringency. LWT-Food Science and Technology, 63(1), 667-676.

Posted by in Enology

Individual differences and effect of phenolic compounds in the immediate and prolonged in-mouth aroma release and retronasal aroma intensity during wine tasting

By Maria Angeles del Pozo Bayón

Phenolic compounds cover the largest fraction of the non-volatile components of wines. Flavonoids (flavonols, anthocyanins and flavan 3-ols) and non-flavonoids (phenolic acids and stilbenes) are the two major classes of wine phenolics. Among them, flavan-3-ols monomers and their oligomers and polymers, which are called proanthocyanidins or condensed tannins, are the most abundant in wine. These compounds have a large contribution to wine sensory characteristics, such as color, astringency and bitterness.
However, phenolic compounds can also affect wine aroma since they can interact with different types of aroma molecules, changing their volatility and modifying aroma release (Pozo-Bayón & Reineccius, 2009). There are many analytical studies focused on determining aroma-phenolic interactions at the molecular level. Most of these works have been conducted using -in vitro approaches (static and dynamic headspace conditions), which although very valuable in determining the chemical nature of aroma-phenolic interactions, do not represent the retronasal delivery of odorants during wine tasting.
In fact, when the wine is introduced into the oral cavity, it is submitted to oral processing. Once in the mouth, wine components (aromatic and nonaromatic compounds) and oral fluids and structures (e.g. saliva, oral mucosa) act together, determining aroma release patterns (Pozo-Bayón, Muñoz-González, & Esteban-Fernández, 2016). However, the chemical and biochemical changes of these odorant compounds during wine oral processing remain scarcely investigated.

Polyphenols might affect aroma release during wine oral processing through the formation of polyphenol-saliva proteins complexes (Mitropoulou, Hatzidimitriou, & Paraskevopoulou, 2011) modifying the transfer of aroma compounds to the exhalation flows that carry out the aromatic molecules to the olfactory receptors. The delayed aroma release from the oral/throat coatings could be behind the long lasting aroma perception (aroma persistence) closely related with wine quality. Therefore, saliva composition might affect this process.

In a recent work (Pérez-Jiménez et al. 2019) we have explore the role of phenolic compounds on oral aroma release during wine tasting, considering the individual effect and establishing whether this effect might also have consequences on aroma perception. In this study, the same rosé wine was supplemented with three types of commercial phenolic extracts. Two of them composed of rich monomers (GSEM-W) and oligomers (GSEO-W) purified fractions obtained from a grape seed extract, and the third one, a red wine extract (RWE-W) mainly composed of anthocyanins. All the wines were aromatized with a target mixture of six wine typical aroma compounds with different physicochemical properties. Oral aroma release was monitored in six volunteers by means of intra-oral SPME at two different times after wine rinsing, just after spiting off the wines (immediate aroma release) and four minutes later (prolonged aroma release). In addition, the sensory meaning of this effect was assessed using a trained panel (n=10) in the recognition and retronasal evaluation of the aromatic descriptors associated to the odorant molecules used to aromatize the wines. An overview of the work can be seen in figure 1.

 

 

Figure 1. Overview of the work.

Figure 2. PCA obtained with oral release data from all individuals at t=0.

Results showed a strong individual effect on total oral aroma release at the two sampling points (t=0 and t=4 minutes after wine expectoration). The first oral aroma monitoring could be more related to the immediate aroma release from oral mucosa, while the second one could be linked to the delayed release, or aroma persistence. These differences on aroma release can be linked to differences in saliva composition. For instance, as it is shown in the results from the principal component analysis (PCA), some aroma compounds (linalool, β-ionone and β-phenylethanol) were highly correlated with saliva total protein content and saliva flow (Figure 2). Individual #4 showed a high oral release of the above mentioned aroma compounds as compared to the rest. This could be related to his saliva composition. This individual had the highest concentration of saliva proteins (2700 µg/mL) and the lowest saliva flow (0.36 mL/min). As lower the salivary flow, lower dilution of aroma compounds and therefore, more aroma compounds will be available to be released to the exhalation flows. On the contrary, the highest saliva protein content of this individual might have affected the retention of aroma compounds, and mainly esters, by saliva proteins through noncovalent interactions has been described (Friel & Taylor, 2001).

 

 

Regarding the effect of phenolic extracts, a general decrease in aroma release after the oral exposure to wines with all phenolic extracts was observed. However this effect was dependent on individual. This happened for all six aroma compounds in individuals #5 and #6, for five compounds in the case of individual #3, and for three compounds in the case of individuals #1 and #4.This situation was very similar in the second monitoring time, in which phenolic compounds also decreased oral aroma release. An example of the effect of phenolic extracts on the oral release of ethyl hexanoate is shown in figure 3. Four minutes after spitting-off the wines, the effect of phenolic extracts was also significant for many aroma compounds, and especially for the two esters, isoamyl acetate and ethyl hexanoate.

 

 

Results from the sensory analysis confirmed that wines with phenolic extracts even at the very low dose like that used in this study (150 mg/L), exhibited significantly lower intensity for the attributes "banana" and "apple" which were associated with the compounds isoamyl acetate and ethyl hexanoate (Figure 4). These compounds were also lower oral released, confirming the good agreement between the -in vivo analytical approach using intra-oral SPME and the sensory findings, at least for these chemical odorants (ester compounds).

 

 

Figure 4. Intensity scores of the aroma descriptors determined by the trained panel (n=10) in the control wine (C-W) and in the wines supplemented with the phenolic extracts (GSEM-W, GSEO-W, RWE-W). Asterisks denote statistically significant differences from ANOVA results (p<0.05).

Figure 3. Oral release of ethyl hexanoate after mouth rinsing with the control wines and the wines spiked with phenolic extracts.

Overall, from a technological point of view this study provides new insights for the development and/or improvement of polyphenol base oenological formulations to enhance wine aroma persistence.
More information about this work can be found in the original article:
Perez-Jiménez, M., Chaya, C., & Pozo-Bayón, M. Á. (2019). Individual differences and effect of phenolic compounds in the immediate and prolonged in-mouth aroma release and retronasal aroma intensity during wine tasting. Food Chemistry. Volume 285, Pages 147-155

 

 

Maria Angeles del Pozo Bayón

Maria Angeles del Pozo Bayón is a Research Scientist at the Institute of Food Science Research (CIAL) in Madrid, which belongs to the Spanish National Research Council (CSIC). She has a graduate Degree in Biology and in Food Science and Technology. During her PhD she studied the effect of technological variables influencing important wine quality markers such as the aroma and phenolic compounds. She was granted with a Marie-Curie postdoctoral fellowship to work at the CSGA-INRA Dijon (France) in aspects related to matrix-aroma interaction and its effect on aroma release. She also was a Postdoctoral Research Associate at the Food Science and Nutrition Department in the University of Minnesota (USA), where she worked on real time aroma monitoring using PTR-MS technique. Currently she has a Tenure position at CIAL, and she is the leader of a National Project focused on investigating the effect of oral physiology on the interindividual differences on wine aroma release and aroma perception and its effect of consumer choice. Recently she has received the ENOFORUM 2018 Award “Spanish Research for Development”. She is the author of numerous publications in scientific and technical journals mainly regarding the topic of flavor chemistry.

 

Those interested in a longer length report can download the working paper at:
https://www.sciencedirect.com/science/article/pii/S0308814619302274

References:

Friel, E., & Taylor, A. (2001). Effect of salivary components on volatile partitioning from solutions. Journal of agricultural and food chemistry, 49(8), 3898-3905.

Mitropoulou, A., Hatzidimitriou, E., & Paraskevopoulou, A. (2011). Aroma release of a model wine solution as influenced by the presence of non-volatile components. Effect of commercial tannin extracts, polysaccharides and artificial saliva. Food research international, 44(5), 1561-1570.

Perez-Jiménez, M., Chaya, C., & Pozo-Bayón, M. Á. (2019). Individual differences and effect of phenolic compounds in the immediate and prolonged in-mouth aroma release and retronasal aroma intensity during wine tasting. Food Chemistry, 285, 147-155.

Pozo-Bayón, M. Á., & Reineccius, G. (2009). Interactions between wine matrix macro-components and aroma compounds. In  Wine chemistry and biochemistry,  (pp. 417-435): Springer.

Pozo-Bayón, M. Á., Muñoz-González, C., & Esteban-Fernández, A. (2016). Wine preference and wine aroma perception. In  Wine Safety, Consumer Preference, and Human Health,  (pp. 139-162): Springer.

Posted by in Enology

Impact of high temperature on red grape flavonoids

By Julia Gouot and Celia Barril

Flavonoids are key compounds for red grape berry and wine quality. Among those, flavonols (UV protectors), anthocyanins (red pigments), flavan-3-ols and tannins (contributing to colour and mouthfeel) are affected by several abiotic factors. In particular, high temperature seems to affect their biosynthesis, accumulation and degradation. Under high temperature, a decrease in total anthocyanins is reported in most cases, while changes in anthocyanin profile, and flavonol and tannin responses are less consistent. This article provides an overview of experimental conditions impacting on flavonoids, including developmental stage, duration, intensity, nocturnal and diurnal temperature ranges, and cultivar diversity of Vitis vinifera L. and interspecific hybrids.
Flavonoids are important secondary metabolites protecting plants against biotic and abiotic stresses and derive from the precursors: phenylalanine, 3-malonyl-CoA and 4-coumaroyl-CoA. They have a common C6-C3-C6 backbone and are divided into sub-families depending on their exact structure and subsequent properties. Three of the main sub-families are flavonols, anthocyanins, and flavan-3-ols giving rise to tannins (Figure 1).

 

Figure 1. Flavonol (A), anthocyanin (B) and tannin (C) chemical structures. Substituent R1, R2 and R3 vary depending on compounds (-OH, -OCH3) (Adapted from Gouot et al, 2018).

To understand the impact of temperature on flavonoid metabolism, experimental methods are required to prevent interactions with light and water status, as they also affect flavonoid biosynthesis (Downey et al, 2006). Direct methods, which modify the fruit or whole-vine temperature involve controlled environments such as glasshouses, growth chambers/cabinets, small climatic chambers, cold rooms or more complex designs such as passive or heated set-ups in the vineyard called open-top chambers (Bonada and Sadras, 2015). Review of the literature highlighted several key parameters to consider when designing an experiment studying temperature:
Plant material. Several plant materials such as vines of different age, field grown or potted vines, grafted or non-grafted, fruiting cuttings, mutant dwarf vines (microvines) have been used. Grapevine variety must also be considered with vines grown in cool climate regions (Aki Queen, Kadainou R-1, Sangiovese and Pinot Noir) appearing more sensitive to temperature while others, well established in hot climate regions (Malbec and Shiraz), maintain their secondary metabolism under high temperature, although they are still affected by more extreme conditions.
Treatment scale. Temperature treatments can be classified into three levels: whole vine, bunch and detached berry or cell suspension (Figure 2). Whole-vine heating experiments have mainly been conducted in controlled environments or using open-top chambers in the field, often with a broader scope of studying the effect of long-term average warming or heat events on photosynthesis, vine development and subsequent changes in berry composition. Other experiments, designed to only change bunch temperature, used chamber-free systems to investigate the effect of temperature on berry metabolism independently of the canopy (Tarara et al, 2000). To complement field and controlled experiments, single berry studies have also been conducted in vitro on detached berries or cell suspension to gain a detailed understanding of flavonoid degradation mechanisms using isotope tracers.

 

 

Figure 2. Summary of the effect of high day temperature on grape flavonoids at different treatment scales: whole vine, bunch and detached berry (Adapted from Gouot et al, 2018).

Duration, intensity and timing. Two main categories depending on the duration of the treatment can be differentiated: short-term, when high temperature is applied for a few hours, or several days, up to 14 (Lecourieux et al, 2017); and long-term, when treatments are applied from several weeks to several months or for the whole season. The imposed temperatures also vary from a couple of degrees Celsius to represent future climate conditions, to a high temperature differential reproducing heat event conditions. Treatments can also be applied at different timings in relation to day and/or night.
Phenological stage. The development stage at which berries are exposed to heat stress is probably the most important parameter to consider, with responses varying depending on the phenological stage. Long-term studies have assessed the effect of a higher average temperature during the whole season: from flowering to maturity or the whole year with interruption during winter. Other studies have focussed on specific growth stages targeting gene expression at a given time of berry development and/or ripening. Early berry development experiments are rare, and most studies have commenced just before the onset of véraison or just after. Véraison, a 24-hour phase when berries begin to colour, has been identified as a particularly sensitive window for abiotic stress responses and anthocyanin biosynthesis. Late ripening experiments have shown a less pronounced effect, or none, on flavonoid profiles, but have impacted concentrations due to degradation and changes in berry water content/size due to shrivelling.
Overall, flavonols do not seem to be directly affected by high temperature but rather more indirectly impacted by a change in primary and secondary metabolism. Flavonols are intermediates in the flavonoid pathway and changes in expression of the genes shared with other flavonoids could explain why they are sometimes affected by temperature. On the other hand, anthocyanins are significantly and directly reduced under high day temperature (Figure 2). Several hypotheses suggest there is a complex combination of enzyme inhibition, up- and down-regulation of phenylpropanoid genes as well as anthocyanin degradation. To date, there is insufficient research on flavan-3-ols to conclude on a direct or indirect temperature effect, especially as very early berry development stages such as flowering have not yet been studied. Tannins have been inconsistently affected and no clear patterns have yet been identified (Cohen et al, 2008, Cohen et al, 2012a, 2012b).

Those interested in a longer length report can download the working paper at:
https://academic.oup.com/jxb/article-abstract/70/2/397/5154969

 

 

 

Julia Gout

Julia Gout completed her education in France and graduated with a Diplome National d'Oenologue and Diplome d’Ingenieur Agronome from ENSA Toulouse. She also studied a Research Master in analytical chemistry/chemometrics at AgroParisTech. She first joined the NWGIC (National Wine and Grape Industry Centre, Charles Sturt University, Australia) to undertake her 6-month Master internship with Dr Celia Barril in 2015. In 2016, she was granted with a scholarship and started her PhD with Dr Barril on the effect of high and extreme high temperatures on Shiraz grape tannin composition.

 

Celia Barril

Dr Celia Barril is a Senior Lecturer in Chemistry at Charles Sturt University (Australia), and currently Course Director in the Faculty of Science. Celia’s research activities make use of her knowledge in organic and analytical chemistry, as applied to current issues in the food, and grape and wine industries. A key theme of her research is the use and development of analytical tools targeted to grape and wine composition, from the impact of canopy management practices and bunch microclimate on grape growing and quality to wine stability quality.

 

References:

Bonada M, Sadras VO. 2015. Review: critical appraisal of methods to investigate the effect of temperature on grapevine berry composition. Australian Journal of Grape and Wine Research 21, 1-17

Cohen SD, Tarara JM, Gambetta GA, Matthews MA, Kennedy JA. 2012a. Impact of diurnal temperature variation on grape berry development, proanthocyanidin accumulation, and the expression of flavonoid pathway genes. Journal of Experimental Botany 63, 2655-2665

Cohen SD, Tarara JM, Kennedy JA. 2008. Assessing the impact of temperature on grape phenolic metabolism. Analytica Chimica Acta 621, 57-67

Cohen SD, Tarara JM, Kennedy JA. 2012b. Diurnal temperature range compression hastens berry development and modifies flavonoid partitioning in grapes. American Journal of Enology and Viticulture 63, 112-120

Downey MO, Dokoozlian NK, Krstic MP. 2006. Cultural practice and environmental impacts on the flavonoid composition of grapes and wine: a review of recent research. American Journal of Enology and Viticulture 57, 257-268

Gouot JC, Smith JP, Holzapfel BP, Walker AR, Barril C. 2018. Grape berry flavonoids: a review of their biochemical responses to high and extreme high temperatures. Journal of Experimental Botany 70, 397-423

Lecourieux F, Kappel C, Pieri P, Charon J, Pillet J, Hilbert G, Renaud C, Gomès E, Delrot S, Lecourieux D. 2017. Dissecting the biochemical and transcriptomic effects of locally applied heat treatment on developing Cabernet Sauvignon grape berries. Frontiers in Plant Science 8, 53

Sadras VO, Bubner R, Moran MA. 2012a. A large-scale, open-top system to increase temperature in realistic vineyard conditions. Agricultural and Forest Meteorology 154–155, 187-194

Tarara JM, Ferguson JC, Spayd SE. 2000. A Chamber-Free Method of Heating and Cooling Grape Clusters in the Vineyard. American Journal of Enology and Viticulture 51, 182-188

Posted by in Viticulture