作者：He, Jiaxian, Xu, Yuantao, Huang, Ding, Fu, Jialing, Liu, Ziang, Wang, Lun, Zhang, Yin, Xu, Rangwei, Li, Li, Deng, Xiuxin and Xu, Qiang
摘要：The citrus transcription factor TRIPTYCHON-LIKE connects regulation of fruit flavor and color by competing with MYB activators; it forms a regulatory loop balancing citric acid and proanthocyanidin accumulation. Deciphering the genetic basis of organoleptic traits is critical for improving the quality of fruits, which greatly shapes their appeal to consumers. Here, we characterize the citrus R3-MYB transcription factor TRIPTYCHON-LIKE (CitTRL), which is closely associated with the levels of citric acid, proanthocyanidins (PAs), and anthocyanins. Overexpression of CitTRL lowered acidity levels and PA contents in citrus calli as well as anthocyanin and PA contents in Arabidopsis leaves and seeds. CitTRL interacts with the two basic helix-loop-helix (bHLH) proteins CitbHLH1 and ANTHOCYANIN 1 (CitAN1) to regulate fruit quality. We show that CitTRL competes with the R2R3-MYB CitRuby1 for binding to CitbHLH1 or CitAN1, thereby repressing their activation of anthocyanin structural genes. CitTRL also competes with a second R2R3-MYB, CitPH4, for binding to CitAN1, thus altering the expression of the vacuolar proton-pump gene PH5 and Leucoanthocyanidin reductase, responsible for vacuolar acidification and proanthocyanidins biosynthesis, respectively. Moreover, CitPH4 activates CitTRL transcription, thus forming an activator-repressor loop to prevent the overaccumulation of citric acid and PAs. Overall, this study demonstrates that CitTRL acts as a repressor of the accumulation of citric acid, PAs, and anthocyanins by a cross-regulation mechanism. Our results provide an opportunity to simultaneously manipulate these key traits as a means to produce citrus fruits that are both visually and organoleptically appealing.
文献注录：He, Jiaxian, Xu, Yuantao, Huang, Ding, Fu, Jialing, Liu, Ziang, Wang, Lun, Zhang, Yin, Xu, Rangwei, Li, Li, Deng, Xiuxin and Xu, Qiang. TRIPTYCHON-LIKE regulates aspects of both fruit flavor and color in citrus [J]. . 2022.
报/刊名：《》，发表于2022
文献类型： [J]
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