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

• Published in: Molecular plant-microbe interactions 2021-11, Vol.34 (11), p.1250-1266
• Main Authors: Li, Chunhong, Wang, Kaituo, Lei, Changyi, Cao, Shifeng, Huang, Yixiao, Ji, Nana, Xu, Feng, Zheng, Yonghua
• Format: Article
• Language: English
• Subjects: 3-Aminobutyric acid; Aminobutyrates; Botrytis; Botrytis cinerea; Defense; defense response; Disease Resistance; Fruit; Fruits; Fungicides; Gene expression; Genes; grape berries; Grapes; Humans; Inoculation; Localization; Metabolism; MYB protein; MYB transcription factor; Phytoalexins; Plant Diseases; Post-harvest decay; Priming; quality maintenance; Resistance to control; Resveratrol; Salicylic acid; Sucrose; Sugar; Transcription; Vitaceae; Vitis - genetics; Vitis vinifera; Yeasts; β-aminobutyric acid
• ISSN: 0894-0282; 1943-7706
• DOI: 10.1094/MPMI-06-21-0142-R

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 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 , 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 -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 , VvMYB44, was isolated and characterized. expression was significantly induced upon the grapes expressed defensive reaction. Subcellular localization, yeast two-hybrid, and coimmunoprecipitation assays revealed that the nuclear-localized physically interacted with the salicylic acid-responsive transcription coactivator NPR1 in vivo for defense expression. In addition, 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 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.