LHCI是植物光系统I（PSI）中与色素分子结合的一系列膜蛋白，由Lhca基因家族编码，主要参与光能的捕获与传递。虽然Lhca基因家族已在拟南芥、水稻、杨树等模式植物中得到了系统鉴定，但在以高光效和高生物量著称的大戟科植物中，至今还未见Lhca类基因的报道。研究基于蓖麻、麻风树、木薯和橡胶树等4种大戟科植物已公布的基因组和EST数据对Lhca基因家族进行全面鉴定，并分析了其基因结构、生化特性及进化关系。结果表明，蓖麻、麻风树、木薯和橡胶树分别含有6、6、9和9个Lhca基因，分属于Lhca1、Lhca2、Lhca3、Lhca4、Lhca5和Lhca6等6个亚家族，每个亚家族含有1~2个成员不等，基因的内含子数目在2~5个之间，部分基因还存在可变剪接形式。进化分析显示，Lhca1和Lhca3亚族具有较早的起源，Lhca2和Lhca6存在于陆生生物中，Lhca4和Lhca5则只存在于高等植物中；在木薯和橡胶树中，Lhca1、Lhca2和Lhca4亚族都出现了基因的扩增。%The Lhca gene family in green plants encodes several light-harvesting chlorophyll a/b-binding (LHC) proteins that collect and transfer light energy to the reaction centers of photosystem I (PSI). Although this gene family is well documented in model plants such arabidopsis, rice and poplar, little information is available in Euphorbiaceae plants which are characterized with high photosynthesis and high biomass. In this study, a genome-wide search was carried out to identify Lhca genes in four genome sequenced Euphorbiaceae plants. As a result, a number of 6, 6, 9 and 9 Lhca genes representing 6 subgene families denoted Lhca1, Lhca2, Lhca3, Lhca4, Lhca5 and Lhca6 were identified from castor bean, physic nut, cassava and rubber tree, respectively. These genes contain 2~5 introns, and some of them were found to have alternative splicing isoforms. The phylogenetic analysis suggests an early origin of sub-gene family Lhca1 and Lhca3 up to unicellular algae, and the subfamily Lhca2 and Lhca6 appeared in land organisms, while the subfamily Lhca4 and Lhca5 presented only in high plants. In cassava and rubber tree plants, the gene amplification was found in the subfamily Lhca1, Lhca2 and Lhca4.
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