Cytochrome P450 CitCYP97B modulates carotenoid accumulation diversity by hydroxylating β-cryptoxanthin in Citrus  

作　　者：Yingzi Zhang Jiajing Jin Nan Wang Quan Sun Di Feng Shenchao Zhu Zexin Wang Shunxin Li Junli Ye Lijun Chai Zongzhou Xie Xiuxin Deng 

机构地区：[1]National Key Laboratory for Germplasm Innovation&Utilization of Horticultural Crops,College of Horticulture and Forestry Sciences,Huazhong Agricultural University,Wuhan 430070,China [2]Hubei Hongshan Laboratory,Wuhan,Hubei 430070,China

出　　处：《Plant Communications》2024年第6期57-72,共16页植物通讯（英文）

基　　金：supported by the National Key Research and Develop-ment Program of China(2022YFF1003100);the National Natural Science Foundation of China(31930095);Modern Agro-industry Technology Research System(CARS-26).

摘　　要：Carotenoids in plant foods provide health benefits by functioning as provitamin A.One ofthe vital provitamin A carotenoids,β-cryptoxanthin,is typically plentiful in citrus fruit.However,little is known about the genetic basis of β-cryptoxanthin accumulation in citrus.Here,we performed a widely targeted metabolomic analysis of 65 major carotenoids and carotenoid derivatives to characterize carotenoid accumulation in Citrus and determine the taxonomic profile of b-cryptoxanthin.We used data from 81 newly sequenced representative accessions and 69 previously sequenced Citrus cultivars to reveal the genetic basis of β-cryptoxanthin accumulation through a genome-wide association study.We identified a causal gene,CitCYP97B,which encodes a cytochrome P450 protein whose substrate and metabolic pathways in land plants were undetermined.We subsequently demonstrated that CitCYP97B functions as a novel monooxygenase that specifically hydroxylates the β-ring of β-cryptoxanthin in a heterologous expression system.In planta experiments provided further evidence that CitCYP97B negatively regulates b-cryptoxanthin content.Using the sequenced Citrus accessions,we found that two critical structural cis-element variations contribute to increased expression of CitCYP97B,thereby altering β-cryptoxanthin accumulation in fruit.Hybridization/introgression appear to have contributed to the prevalence of two cis-element variations in different Citrus types during citrus evolution.Overall,these findings extend our understanding of the regulation and diversity of carotenoid metabolism in fruit crops and provide a genetic target for production of β-cryptoxanthin-biofortified products.

关 键 词：carotenoids β-cryptoxanthin cytochrome P450 CYP97B HYDROXYLATION 

分 类 号：Q94[生物学—植物学]