Unraveling betalain suppression in pitaya:insights from co-activator HuMYB9 binding at HuCYP76AD1-1,HuADH1,and HuDODA1 super-enhancers  

作　　者：Fangfang Xie Kamran Shah Canbin Chen Irfan Ali Sabir Jiayi Chen Jiaxuan Chen Jianye Chen Yonghua Qin 

机构地区：[1]Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables/Key Laboratory of Biology and Genetic Improvement of Horticultural Crops(South China),Ministry of Agriculture and Rural Affairs,College of Horticulture,South China Agricultural University,Guangzhou,China [2]Department of Horticulture,College of Agriculture,Guangxi University,Nanning,China

出　　处：《Food Quality and Safety》2024年第2期404-413,共10页食品品质与安全研究（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.31972367);the Science and Technology Program of Yangjiang(No.yangketong[2021]50);the Provincial Rural Revitalization Strategy Special Project of Guangdong in 2022(No.2022-NPY-00-034),China.

摘　　要：Objectives:Myeloblastosis(MYB)proteins,recognized as crucial transcriptional regulators,play an integral role in orchestrating the range of plant colors.Materials and Methods:Pitaya(Hylocereus spp.),a distinctive commercially cultivated fruit,stands apart due to its unique betalains,water-soluble nitrogen-enriched pigments that confer its vibrant hues.Although betalain biosynthesis has been extensively explored,the potential infuence of co-activators that might disrupt pigment production remains relatively unexplored.Results:In this study,we found that HuMYB9,an R2R3-MYB repressor,exhibited a remarkable decreasing during pitaya maturation.Sequence alignment analyses showed conserved R2 and R3 domains within the C-terminal of HuMYB9.HuMYB9’s regulatory activities were found to be nuclear localized and it interacted with specifc elements within the promoters of HuDODA1,HuADH1,and HuCYP76AD1-1,thus infuencing the transcriptional activities in vitro.HuMYB9 transiently downregulated the expression of key betalain biosynthetic genes with a corresponding effect on the levels of pitaya pulp betalains.Conclusions:Our results suggest that HuMYB9 operates as a suppressor,specifcally downregulating the expression of HuCYP76AD1-1,HuDODA1,and HuADH,thereby modulating betalain biosynthesis in pitaya.Collectively,our fndings provide invaluable insights into the regulation of betalain accumulation in pitaya.

关 键 词：BETALAINS color pigments CACTUS MYB transcription factor PITAYA 

分 类 号：Q78[生物学—分子生物学]