掌叶覆盆子HMGR基因家族的鉴定及表达分析

Identification and Expression Analysis of HMGR Gene Family in Rubus chingii Hu

3-羟基-3-甲基戊二酰辅酶A还原酶(HMGR)是药用植物萜类产物骨架生物合成的重要酶之一。为了明确掌叶覆盆子HMGR蛋白的功能,使用生物信息学手段对RcHMGR家族成员的分类、基因结构、染色体定位、启动子信息等进行了系统分析,并比较了不同组织、果实不同成熟阶段及MeJA处理下RcHMGR基因的表达量。结果表明,RcHMGR基因家族共有7个成员,分布于3条染色体上,编码444~601 aa蛋白序列。RcHMGR蛋白分为4个亚家族,亚细胞定位于内质网,均含有HMGR保守功能域。RcHMGR家族基因的启动子上包含激素响应、光响应和低温响应等多种顺式元件。RcHMGR家族基因在掌叶覆盆子不同组织、果实不同成熟阶段和MeJA处理下的表达量均存在显著差异,其中RcHMGR5在果实中高丰度表达,并受到MeJA强烈诱导,与类胡萝卜素在掌叶覆盆子果实中的积累规律相一致,推测是类胡萝卜素合成途径的关键酶。上述结果为后续研究RcHMGR基因家族在萜类生物合成中的功能奠定了基础。

3-hydroxy-3-methylglutaryl coenzyme A reductase(HMGR)is one of the most significant enzymes for the terpene biosynthesis in medicinal plants.To explicit the function of HMGR gene family in Rubus chingii Hu,the classification,gene structure,chromosomal distribution,and promoter information of RcHMGR members were systematically analyzed through bioinformatical methods.The expression levels were comparatively detected in different tissues,different stages of fruit development,and under the treatment of methyl jasmonate(MeJA).The results demonstrated that a total of 7 RcHMGR members were mined,which were located on 7 chromosomes,encoding 444-601 aa protein sequences.RcHMGR were divided into four subfamilies,located in the endoplasmic reticulum,and harbored the highly conserved HMGR domains.Multiple cis-acting elements including hormone,light,and low-temperature responses were presented in the promoter regions of RcHMGR family genes.RcHMGR family genes were differentially expressed in different tissues(roots,stems,leaves,flowers,and fruits),different fruit development stages(small green fruits,big green fruits,yellow fruits,and red fruits),and treatment of MeJA.Among them,RcHMGR5 was highly expressed in fruits of R.chingii,and induced by MeJA,which was coincided with the accumulation of carotenoids,suggesting that RcHMGR5 might be a critical enzyme involved in carotenoid biosynthesis.These results laid a foundation for in-depth study on the role of RcHMGR family genes in R.chingii.