The study of hormonal metabolism of Trincadeira and Syrah cultivars indicates new roles of salicylic acid, jasmonates, ABA and IAA during grape ripening and upon infection with Botrytis cinerea

Abstract

Hormones play an important role in fruit ripening and in response to biotic stress. Nevertheless, analyses of hormonal profiling during plant development and defense are scarce. In this work, changes in hormonal metabolism in grapevine (Vitis vinifera) were compared between a susceptible (Trincadeira) and a tolerant (Syrah) variety during grape ripening and upon infection with Botrytis cinerea. Infection of grapes with the necrotrophic pathogen Botrytis cinerea leads to significant economic losses worldwide. Peppercorn-sized fruits were infected in the field and mock-treated and infected berries were collected at green, veraison and harvest stages for hormone analysis and targeted qPCR analysis of genes involved in hormonal metabolism and signaling. Results indicate a substantial reprogramming of hormonal metabolism during grape ripening and in response to fungal attack. Syrah and Trincadeira presented differences in the metabolism of abscisic acid (ABA), indole-3-acetic acid (IAA) and jasmonates during grape ripening that may be connected to fruit quality. On the other hand, high basal levels of salicylic acid (SA), jasmonates and IAA at an early stage of ripening, together with activated SA, jasmonates and IAA signaling, likely enable a fast defense response leading to grape resistance/ tolerance towards B. cinerea. The balance among the different phytohormones seems to depend on the ripening stage and on the intraspecific genetic background and may be fundamental in providing resistance or susceptibility. In addition, this study indicated the involvement of SA and IAA in defense against necrotrophic pathogens and gains insights into possible strategies for conventional breeding and/or gene editing aiming at improving grape quality and grape resistance against Botrytis cinerea.

VvSWEET7 Is a Mono- and Disaccharide Transporter Up-Regulated in Response to Botrytis cinerea Infection in Grape Berries

“…Grape berry clusters showed clear symptoms of infection at the green (EL32), veraison (EL35), and fully mature stages (EL38), which were very similar among infected clusters that were confirmed by amplification by qPCR of specific fungal genomic DNA as previously reported in Figure 2 by Coelho et al (2019). Also, visual symptoms of infection can be seen in Supplementary Figure 1.…”

“…Clusters of Trincadeira grapes were infected by inoculation with a conidial suspension of B. cinerea at EL29 (peppercorn-size, early green stage) in very well-established and standardized conditions according to Agudelo-Romero et al (2015) and Coelho et al (2019). Inoculation was performed at the same time in multiple clusters in very similar conditions, particularly in size, appearance, exposure to light, canopy densities, and plant orientation between them and also identical to control clusters.…”

Phytohormone profiles are strongly altered during induction and symptom development of the physiological ripening disorder berry shrivel in grapevine

“…5e). Recently a cultivar specificity of the expression profile of this gene was described (Coelho et al 2019), which supports the pattern observed in 2013 in our study.…”

“…In accordance, high ABA content without the expression of ABA biosynthesis genes have also been described in grape berries at softening and at veraison (Castellarin et al 2016;Coelho et al 2019). A cultivar-dependency was observed and it was proposed that the ABA increase at veraison might be caused by ABA import from other tissues or its lower turnover, which is supported by a decreased expression of ABA 8′-hydroxylases (Coelho et al 2019). In BS-berries, the ABA content was slightly lower until veraison and higher thereafter (no significant values).…”

Transcriptome Analysis Identifies Two Ethylene Response Factors That Regulate Proanthocyanidin Biosynthesis During Malus Crabapple Fruit Development

“…Moreover, previous research has shown that the ABA signaling network promotes flavonol biosynthesis (especially of quercetin derivatives) in early land plants (Brunetti et al, 2019). These results showed that phytohormones play important roles in the development and ripening of fruit and are also involved in flavonoid biosynthesis (Coelho et al, 2019). In our research, many DEGs related to 'plant hormone signal transduction' were enriched throughout fruit development, suggesting a correlation between plant hormones and PA biosynthesis in Malus crabapple fruit ( Figure 2).…”