药用植物铁皮石斛ABC转运蛋白基因的鉴定及其差异表达分析

Identification and differential expression analysis of ABC transporter gene from medicinal plant Dendrobium officinale

ABC转运蛋白(ATP-binding cassette transporters)是一类普遍存在于原核生物和真核生物中的跨膜转运蛋白,在植物次生代谢物质的转运与积累、植物激素运输、脂质代谢、外源毒素的解毒、植物抗病等方面都起着关键作用。本研究基于铁皮石斛基因组和转录组数据,初步鉴定了88个铁皮石斛ABC转运蛋白,并预测了其功能及亚细胞定位。这些蛋白分为ABCA-ABCI等7个亚家族,包括4个ABCA、19个ABCB、12个ABCC、3个ABCD、9个ABCF、37个ABCG和4个ABCI,主要定位在细胞质膜、液泡及高尔基体上。结合转录组数据比较分析了铁皮石斛种子无菌及接菌共生萌发过程中ABC转运蛋白表达模式。结果表明ABCB和ABCG蛋白家族部分成员在种子接菌共生萌发过程中显著差异上调表达。荧光实时定量PCR结果显示,与无菌萌发相比,2个ABCG-PDR基因和2个ABCB11基因在铁皮石斛种子接菌共生萌发组中显著高表达(fold change≥10.0)。基于蛋白同源性分析,预测这些蛋白主要参与了脱落酸、生长素等激素的运输,暗示这些蛋白在铁皮石斛种子萌发及与微生物相互作用过程中发挥重要作用。

ABC transporters（ATP-binding cassette transporters） are a family of trans-membrane transport proteins, which are ubiquitous in prokaryotes and eukaryotes. They are functionallyinvolved in the transport and accumulation of plant secondary metabolites, phytohormone transport, lipid metabolism, exogenous toxins detoxification, plant disease and other aspects. Based on the genome and transcriptome data of Dendrobium officinale, 88 ABC transporters were preliminarily identified in D. officinale and their functions and subcellular localization were predicted. These proteins are divided into seven subfamilies, ABCA-ABCI, including 4 ABCA, 19 ABCB, 12 ABCC, 3 ABCD, 9 ABCF, 37 ABCG and 4 ABCI, which are mainly located in plasma membrane, vacuole and Golgi apparatus. Comparative transcriptomic analysis of ABC protein expression profile between asymbiotic and symbiotic germination of D. officinale show that some members of ABCB and ABCG proteins are highly expressed during seed germination inoculated fungi. q PCR validated that 2 ABCB11 and 2 ABCG-PDR are significantly up-regulated in symbiotic assay compared to asymbiotic germination（fold change ≥10.0）. These proteins are mainly involved in abscisic acid and auxin transport, suggesting that these proteins play an important role in the germination of D. officinale seed and in the interaction with microorganisms.