Alterations in Sucrose and Phenylpropanoid Metabolism Affected by BABA-Primed Defense in Postharvest Grapes and the Associated Transcriptional Mechanism

Abstract

Defense elicitors can induce fruit disease resistance to control postharvest decay but may incur quality impairment. Our present work aimed to investigate the resistance against Botrytis cinerea induced by the elicitor β-aminobutyric acid (BABA) and to elucidate the specific transcriptional mechanism implicated in defense-related metabolic regulations. The functional dissection results demonstrated that, after inoculation with the fungal necrotroph B. cinerea, a suite of critical genes encoding enzymes related to the sucrose metabolism and phenylpropanoid pathway in priming defense in grapes were transcriptionally induced by treatment with 10 mM BABA. In contrast, more UDP-glucose, a shared precursor of phenylpropanoid and sucrose metabolism, may be redirected to the phenylpropanoid pathway for the synthesis of phytoalexins, including trans-resveratrol and ɛ-viniferin, in 100 mM BABA–treated grapes, resulting in direct resistance but compromised soluble sugar contents. An R2R3-type MYB protein from Vitis vinifera, VvMYB44, was isolated and characterized. VvMYB44 expression was significantly induced upon the grapes expressed defensive reaction. Subcellular localization, yeast two-hybrid, and coimmunoprecipitation assays revealed that the nuclear-localized VvMYB44 physically interacted with the salicylic acid–responsive transcription coactivator NPR1 in vivo for defense expression. In addition, VvMYB44 directly bound to the promoter regions of sucrose and phenylpropanoid metabolism-related genes and transactivated their expression, thus tipping the balance of antifungal compound accumulation and soluble sugar maintenance. Hence, these results suggest that 2R-type VvMYB44 might be a potential positive participant in BABA-induced priming defense in grape berries that contributes to avoiding the excessive consumption of soluble sugars during the postharvest storage. [Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

D-Tagatose-Based Product Triggers Sweet Immunity and Resistance of Grapevine to Downy Mildew, but Not to Gray Mold Disease

“…A direct connection between D-tagatose and D-glucose metabolism has been reported in the oomycete P. infestans [ 27 ]. D-glucose may also be redirected to the phenylpropanoid pathway for the synthesis of phytoalexins, resulting in enhanced resistance [ 58 ]. Structural similarity of D-tagatose with common sugars is probably a crucial factor contributing to its effect.…”

Priming seeds for the future: Plant immune memory and application in crop protection

“…RNA-seq and comparative transcriptomic analysis revealed that treatment of grapes with 100 mM BABA relatively upregulated genes associated with phenylpropanoid biosynthesis compared with grapes subjected to 10 mM BABA treatment. These results suggested that the BABA-primed defense determines alterations in sucrose and phenylpropanoid metabolism in postharvest grapes (Li et al, 2021a). Interestingly, the grape MYB-type transcription factor VvMYB44 directly activates the expression of sucrose and phenylpropanoid metabolism-related genes, and might participate in BABA-induced priming (Li et al, 2021a).…”

“…These results suggested that the BABA-primed defense determines alterations in sucrose and phenylpropanoid metabolism in postharvest grapes (Li et al, 2021a). Interestingly, the grape MYB-type transcription factor VvMYB44 directly activates the expression of sucrose and phenylpropanoid metabolism-related genes, and might participate in BABA-induced priming (Li et al, 2021a).…”

“…To prepare for the incoming pathogens, primed plants usually undergo metabolic changes in the biosynthesis of primary and secondary metabolites (Frost et al, 2008;War et al, 2011;Brosset and Blande, 2022). It was recently demonstrated that BABA treatment induced resistance to Botrytis cinerea and affected the contents of soluble sugar and phenylpropanoid metabolites in grape berries (Li et al, 2021a). RNA-seq and comparative transcriptomic analysis revealed that treatment of grapes with 100 mM BABA relatively upregulated genes associated with phenylpropanoid biosynthesis compared with grapes subjected to 10 mM BABA treatment.…”

Transcriptional profiling of defense responses to Botrytis cinerea infection in leaves of Fragaria vesca plants soil-drenched with β-aminobutyric acid

“…The Mapman analysis confirmed the GO enrichment data, showing that major metabolic pathways were similarly induced following infection in both BABA-treated and untreated plants, although some bins within each pathway were differently expressed between treatments. BABA has been shown to induce expression of genes involved in phenylpropanoid and salicylic acid (SA) biosynthesis associated with reduced decay incidence when applied locally ( Li et al., 2021 ). However, except for the reduced expression of genes involved in photosynthesis the induced susceptibility observed in our study does not seem to be explained by induction or repression of major metabolic pathways, but rather by differential expression of individual genes that might induce susceptibility.…”