Proteins involved in biotic and abiotic stress responses as the most significant biomarkers in the ripening of Pinot Noir skins

Abstract

We propose an integrated approach, obtained by the combination of multivariate statistics and proteomics, useful to isolate candidate biomarkers for the evaluation of grape ripening. We carried out a comparative 2-DE analysis of grape skins collected in three moments of ripening and analyzed the spot volume dataset through the application of principal component analysis followed by forward stepwiselinear discriminant analysis. This technique allowed to discriminate véraison, quite mature and mature samples, and to sort the matched spots according to their significance. We identified 36 spots showing high discriminating coefficients through liquid chromatography -electrospray ionization -tandem mass spectrometry (LC-ESI-MS/MS). Most of them were involved in biotic and abiotic stress responses indicating these enzymes as good candidate markers of berry ripening. These evidences hint at a likely developmental role of these proteins, in addition to their reported activity in stress events. Restricting the same statistical analysis to the samples belonging to the two last stages, it was indicated that this approach can clearly distinguish these close and similar phases of berry development. Taken all together, these results bear out that the employment of the combination of 2-DE and multivariate statistics is a reliable tool in the identification of new protein markers for describing the ripening phases and to assess the overall quality of the fruit.

Decrease in Fruit Moisture Content Heralds and Might Launch the Onset of Ripening Processes

“…Furthermore, multiple stress‐related transcripts accompany ripening in grape berry (Pilati and others 2003) and in tomato fruit (Srivastava and others 2010). Accordingly, stress‐response proteins have been shown to be the most expressed during early stages of véraison (ripening) in grape berry (Negri and others 2008) and singled out as good candidate markers for grape berry ripening (Negri and others 2011). Stress‐induced fruit ripening might be akin to stress‐induced leaf senescence (Lim and others 2007) or other senescence phenomena in plants (Guo and Gan 2005) and, characterized by expression of senescence‐associated stress genes in plants (Weaver and others 1998).…”

The onset of grapevine berry ripening is characterized by ROS accumulation and lipoxygenase-mediated membrane peroxidation in the skin

“…It differs at only five out of 901 residues from the Sauvignon Blanc orthologue [41]. The véraison-specific expression profile of this LOX isoform (Figures 7 and 8) was already highlighted in a proteomic study which proposed it as a biomarker of grapevine ripening [53]. According to the Vitis atlas [42] other two 13- LOX genes are expressed in the berry, but with a descending profile from fruit set to full ripening.…”

Proteomic analysis of apricot fruit during ripening

“…Other allergens, such as sequence-related major allergen Pru p1 (spots 84 and 85), Pru p1.06B (spots 81 and 91) and Pru ar1 (spots 79 and 80) species, generally showed reduced levels during ripening, except one spot. These pathogenesisrelated (PR) proteins are present at a variable level in different Rosaceae tissues upon pathogen fruit infection, ripening and softening [11,15,20,[25][26][27][28][29]79]. They are the causative agents of the birch pollen-related food allergy.…”

“…Detailed comprehension of genetic regulatory elements is central for a full understanding of fruit ripening; in this context, proteomics represents a powerful approach to characterize biochemical networks and to establish functional correlations between genotype and phenotype [10]. Thus, differential proteomic studies on immature and mature fruits have been accomplished on tomato [11,12], grape [13][14][15][16][17][18][19][20], orange [21,22], peach [23][24][25][26][27][28], strawberry [29], mango [30], papaya [31,32] and apple [33,34] pericarp; some investigations were conducted on selected tissues, such as exocarp or mesocarp [14][15][16][17][18][20][21][22][23]25,27,28,30,31]. These studies described a tissuedependent proteome repertoire that present distinctive changes during fruit ripening.…”