The Transcriptional Responses and Metabolic Consequences of Acclimation to Elevated Light Exposure in Grapevine Berries

Abstract

An increasing number of field studies that focus on grapevine berry development and ripening implement systems biology approaches; the results are highlighting not only the intricacies of the developmental programming/reprogramming that occurs, but also the complexity of how profoundly the microclimate influences the metabolism of the berry throughout the different stages of development. In a previous study we confirmed that a leaf removal treatment to Sauvignon Blanc grapes, grown in a highly characterized vineyard, primarily affected the level of light exposure to the berries throughout their development. A full transcriptomic analysis of berries from this model vineyard details the underlying molecular responses of the berries in reaction to the exposure and show how the berries acclimated to the imposing light stress. Gene expression involved in the protection of the photosynthetic machinery through rapid protein-turnover and the expression of photoprotective flavonoid compounds were most significantly affected in green berries. Overall, the transcriptome analysis showed that the berries implemented multiple stress-mitigation strategies in parallel and metabolite analysis was used to support the main findings. Combining the transcriptome data and amino acid profiling provided evidence that amino acid catabolism probably contributed to the mitigation of a likely energetic deficit created by the upregulation of (energetically) costly stress defense mechanisms. Furthermore, the rapid turnover of essential proteins involved in the maintenance of primary metabolism and growth in the photosynthetically active grapes appeared to provide precursors for the production of protective secondary metabolites such as apocarotenoids and flavonols in the ripening stages of the berries. Taken together, these results confirmed that the green grape berries responded to light stress much like other vegetative organs and were able to acclimate to the increased exposure, managing their metabolism and energy requirements to sustain the developmental cycle toward ripening. The typical metabolic consequences of leaf removal on grape berries can therefore now be linked to increased light exposure through mechanisms of photoprotection in green berries that leads toward acclimation responses that remain intact until ripening.

Biosynthesis and Cellular Functions of Tartaric Acid in Grapevines

“…For example, Asc acts as an enzyme cofactor and modulator of enzyme activity in the thylakoid membrane (Müller-Moulé et al, 2004), a reducing agent in the chloroplast (Krieger-Liszkay et al, 2008), a substrate for ethylene biosynthesis (Mirica and Klinman, 2008), and has roles in regulation of cell expansion, fruit-ripening and softening in the apoplast (Green and Fry, 2005;Gilbert et al, 2009). Physiological roles of Asc in plants also include defense (Conklin et al, 1996), growth and development (Dowdle et al, 2007), hormone and pathogen responses (Pastori et al, 2003) and programmed cell death (de Pinto et al, 2006). The redox couple Asc to DHA can influence the cellular redox state, which may be an important component in ROS signaling (Foyer and Noctor, 2005;Noctor, 2006).…”

“…For the purpose of this analysis we assumed that VvLidh (VIT_16s0100g00290) represents transcripts of both VvLidh1 and VvLidh3 . Most datasets ( Table 1 ) exhibited no changes in expression of VvLidh nor Vv2kgr (VIT_09s0002g04300), including experiments featuring water limitation ( Berdeja et al, 2015 ; Catacchio et al, 2019 ), cold night temperature ( Sawicki et al, 2019 ), elevated light ( du Plessis et al, 2017 ), diurnal regulation ( Rienth et al, 2014 ), salt stress in leaves ( Upadhyay et al, 2018 ; Das and Majumder, 2019 ), increased source-sink ratio via cluster thinning ( Pastore et al, 2011 ), copper stress ( Leng et al, 2015 ) and abscisic acid application ( Rattanakon et al, 2016 ; Pilati et al, 2017 ). In an experiment reporting the differential terroir effect on Cabernet Sauvignon berries in Bordeaux and Reno, there was also no change, but these experimental samples were skins collected during late ripening so expression of VvLidh was likely low anyway ( Cramer et al, 2020 ).…”

Exploratory study of sugar andC6compounds in single berries of grapevine (Vitis viniferaL.) cv. Cabernet Sauvignon throughout ripening

“…Analytically, sugar is easy to determine and indirect measurements have allowed an accurate quantification in most cases (Cozzolino et al 2006, 2011, Iland et al 2013). Conversely, secondary metabolites are present in grapes at much lower concentration and their accumulation is often dependent on the environmental conditions at the microclimate level (Costantini et al 2017, Du Plessis et al 2017, Lecourieux et al 2017).…”

“…This justifies ongoing attempts to understand how grape metabolites are synthesised and the hierarchy of factors inducing changes in berry composition during development and ripening. The development of aroma compounds in grapes is influenced by genotypic expression, environmental conditions and growing practices applied in the vineyard that modify grape microclimate, as well as the specific interactions between these factors (Pastore et al 2013, Savoi et al 2016, Costantini et al 2017, Du Plessis et al 2017, Lecourieux et al 2017).…”

Molecular Tools for Adapting Viticulture to Climate Change

“…Full coverage of the grapevine transcriptome was finally achieved by the use of next-generation deep RNA-sequencing (RNA-seq; Zenoni et al, 2010 ), which provides greater flexibility than microarrays, allowing to work with genotypes distant to the grape reference genome, including non- vinifera Vitis species. Both genome-wide microarrays and RNA-seq have been used to characterize the response of grapevine to drought stress ( Berdeja et al, 2015 ; Corso et al, 2015 ), UV-B/light intensities ( Carbonell-Bejerano et al, 2014 ; du Plessis et al, 2017 ), and elevated temperature ( Rienth et al, 2014 , 2016 ; Lecourieux et al, 2017 ). Such high-throughput transcriptomics can highlight relevant candidate genes for future breeding programs tailored to produce new grape cultivars better adapted to anticipated climate change conditions, provided that two conditions are met.…”