The IAA-and ABA-responsive transcription factor CgMYB58 upregulates lignin biosynthesis and triggers juice sac granulation in pummelo  

作　　者：Meiyan Shi Xiao Liu Haipeng Zhang Zhenyu He Hongbin Yang Jiajing Chen Jia Feng Wenhui Yang Youwu Jiang Jia-Long Yao Cecilia Hong Deng Juan Xu 

机构地区：[1]Key Laboratory of Horticultural Plant Biology,Ministry of Education,Wuhan,Hubei 430070,China [2]The New Zealand Institute for Plant and Food Research Limited,Private Bag 92169,Auckland 1142,New Zealand

出　　处：《Horticulture Research》2020年第1期846-859,共14页园艺研究（英文）

基　　金：supported by the National Key Research and Development Program of China(2018YFD1000204);the National Natural Science Foundation of China(31672102).

摘　　要：In citrus,lignin overaccumulation in the juice sac results in granulation and an unpleasant fruit texture and taste.By integrating metabolic phenotyping and transcriptomic analyses,we found 702 differentially expressed genes(DEGs),including 24 transcription factors(TFs),to be significantly correlated with lignin content.CgMYB58 was further identified as a critical R2R3 MYB TF involved in lignin overaccumulation owing to its high transcript levels in Huanong Red-fleshed pummelo(HR,Citrus grandis)fruits.Transient expression of CgMYB58 led to an increase in the lignin content in the pummelo fruit mesocarp,whereas its stable overexpression significantly promoted lignin accumulation and upregulated 19 lignin biosynthetic genes.Among these genes,CgPAL1,CgPAL2,Cg4CL1,and CgC3H were directly modulated by CgMYB58 through interaction with their promoter regions.Moreover,we showed that juice sac granulation in pummelo fruits could be affected by indole-3-acetic acid(IAA)and abscisic acid(ABA)treatments.In HR pummelo,ABA significantly accelerated this granulation,whereas IAA effectively inhibited this process.Taken together,these results provide novel insight into the lignin accumulation mechanism in citrus fruits.We also revealed the theoretical basis via exogenous IAA application,which repressed the expression of CgMYB58 and its target genes,thus alleviating juice sac granulation in orchards.

关 键 词：integrating treatment CITRUS 

分 类 号：S666.3[农业科学—果树学]