大戟科植物MVK基因家族的全基因组鉴定与分析

Genome-Wide Identification and Analysis of MVK Gene Family in Euphorbiaceae Plants

基于已公布的基因组和EST数据,对蓖麻、麻疯树、木薯和橡胶树4种大戟科植物的MVK基因家族进行系统鉴定,并在此基础上分析其基因结构与进化关系。结果表明,这4种植物均含有2个MVK基因,所有基因均含有4个内含子。同源分析表明,MVK广泛存在于各种古细菌、真细菌和真核生物中,显示出较早的起源;虽然MVK在大多数基因组已测序的物种中主要以单拷贝的形式存在,但在所研究的4种大戟科植物中均出现了基因加倍现象,这与玉米和杨树类似。基因表达谱分析显示,在蓖麻的叶片、花、II/III期胚乳、V/VI期胚乳和种子等组织中,RcMVK1的表达丰度总体高于RcMVK2;虽然2个基因表达丰度最高的组织均为II/III期胚乳,但丰度最低的组织却分别为种子和叶片。

The mevalonate kinase （MVK） gene family of four plant species from Euphorbiaceae family i. e. , castor bean （ Ricinus communis） , physic nut （ Jatropha curcas） , cassava （ Manihot esculenta） and rub- ber tree （Hevea brasiliensis） was identified systematically based on the published genome-wide and EST data, and the gene structure and the revolutionary relations of these species were analyzed consequently. The results showed that there were 2 MVK genes in all of the four plant species respectively, and all of the genes contained 4 introns. Homologous analyses revealed that MVK genes were widely distributed in different organisms inclu- ding archaea, eubacteria and eukaryotes, suggesting an early origin of this gene family. Although a single copy of MVK gene was identified in most genome released species, gene amplification was found in these four Eu- phorbiaceae plant species similarly as in maize and poplar. The analyses on digital expression profiling sugges- ted that in the leaf, flower, II/III stage endosperm, V/VI stage endosperm and seed organ tissues, the expres- sion level of RcMVK1 was generally higher than that of RcMVK2. The highest expression of both the two genes was found in II/III stage endosperm, the lowest expression of RcMVK1 was in seed, whereas the lowest expres- sion of RcMVK2 was in leaf tissue.