Improving berry quality and antioxidant ability in ‘Ruidu Hongyu’ grapevine through preharvest exogenous 2,4-epibrassinolide, jasmonic acid and their signaling inhibitors by regulating endogenous phytohormones

Abstract

Grape berries contain a variety of metabolites, such as anthocyanins, sugars, fatty acids, and antioxidants. Endogenous phytohormones strongly influence these metabolites, which regulate berry quality improvement. In this study, we evaluated the effects of 2,4-epibrassinolide (EBR, brassinolide (BR)-like growth regulator), jasmonic acid (JA), and their signaling inhibitors brassinazole (Brz), and sodium diethyldithiocarbamate (DIECA) on berry quality and antioxidant ability. Overall, the pre-harvest application of 0.5 mg L-1 EBR and 100 μmol L-1 JA significantly influences the quality of the grape berry. Results showed that EBR was superior to other treatments at enhancing the content of different metabolites, including anthocyanins, fructose, glucose, and a variety of fatty acids, in grapes. EBR and JA also enhanced the synthesis of gibberellin3 (GA3), cytokinin (CTK), salicylic acid (SA), JA, methyl jasmonate (MeJA), BR, and abscisic acid (ABA), while inhibiting the synthesis of auxin (IAA). Most genes related to BR/JA and anthocyanins/sugars/fatty acids biosynthesis were up-regulated. The effects of Brz and DIECA on the grape berry quality were totally reversed throughout the study, as shown by EBR and JA. According to correlation analysis, EBR and JA have a beneficial positive interaction that promotes the formation of strong coherences in grape berries between ABA/IAA/ZT-fruit expansion, BR/JA/MeJA/GA3/ZR-biochemical characteristics development, JA/MeJA/ABA/GA3/SA/ZR-antioxidant capacity enhancement, and JA/MeJA/IAA/GA3/ZT/ZR-fatty acids accumulation. In this regard, we concluded that preharvest exogenous 0.5 mg L-1 EBR and 100 μmol L-1 JA is a successful way to improve grape berry quality.

EBR and JA regulate aroma substance biosynthesis in ‘Ruidu Hongyu’ grapevine berries by transcriptome and metabolite combined analysis

“…Similarly, JA could also contribute to berry expansion, sugar accumulation, and anthocyanins formation ( Yu et al., 2020 ; Gao et al., 2022 ; Wang et al., 2022 ). In agreement with the results of previous research ( Li et al., 2022 ), this study further verified the results that EBR and JA also promoted the biochemical properties of ‘Ruidu Hongyu’ grapevine. We investigated more closely than in the previous study to assess the effect of EBR and JA on the biosynthesis of grape berry free-form aroma volatiles.…”

“…These further authenticated that the increase of terpenes and aldehydes contents might be regulated by exogenous EBR and JA signals. The outcomes were more consistent with previous findings that the exogenous EBR and JA were involved in regulating the biosynthesis of several metabolites, including monosaccharides, anthocyanins, fatty acids, amino acids, and so on, with significantly higher levels than the CK group ( Mao et al., 2017 ; Vergara et al., 2018 ; Nakajima et al., 2021 ; Chen et al., 2022 ; Li et al., 2022 ; Lv et al., 2022a ). Results of this study provided reference information for verifying the interaction of EBR and JA in regulating aroma substances biosynthesis.…”

“…Moreover, it was found that exogenous EBR and JA were primarily responsible for the production of rose-aroma characteristics of grape berries. The aforementioned findings supported earlier research that showed exogenous EBR and JA promoted aroma volatilization and flavor improvement ( Xi et al., 2013 ; Li et al., 2022 ; Wang et al., 2022 ).…”

“…Exogenous phytohormones are used to improve the berries’ quality while the grapevine is growing and developing. According to prior research, EBR could significantly increase grape berry size and sugar content as well as improved grape color and flavor formation ( Li et al., 2022 ; Lv et al., 2022a ). Similarly, JA could also contribute to berry expansion, sugar accumulation, and anthocyanins formation ( Yu et al., 2020 ; Gao et al., 2022 ; Wang et al., 2022 ).…”

“…‘Ruidu Hongyu’ grapevine, as a table grape cultivar in China, has various advantageous traits including high-yield, pink coloring and precocity ( Xu et al., 2014 ). Previously, the effect of EBR and JA on berry quality was evaluated, and they were responsible for improving anthocyanin, fatty acid, and sugar levels ( Li et al., 2022 ). However, the mechanism of exogenous BR and JA regulation on aroma volatilization of ‘Ruidu Hongyu’ grapevine has yet to be addressed.…”