陆地棉GhSUMO基因的克隆与黄萎病菌诱导表达分析

SUMO化修饰与植物抗病防御、信号转导和耐旱等有着直接的关系。本文以抑制差减杂交（sup—pression subtractive hybridization．SSH）技术获得SUMO的EST为信息探针，对棉花EST数据库进行同源搜索和电子克隆，获得了全长为396bp的SUMO基因编码区cDNA全长，我们将该基因命名为GhSUMO，推测该基因编码95个氨基酸。分别以抗黄萎病陆地棉品种豫棉21号的cDNA和DNA为模板，对该基因进行了PCR扩增验证，测序结果表明，GhSUMO基因序列与电子克隆序列一致，且没有内含子。蛋白序列分析表明，该蛋白具有保守泛素结构域和C端双Gly的断裂／连接位点，以及保守的疏水表面和Ulpl—Smt3互作位点。系统进化分析表明，该蛋白与蓖麻的同源序列表现了最高的相似性，与其它双子叶植物同源序列次之，而与单子叶植物的相似性较低。棉苗接菌后实时定量PCR结果显示，该基因表达量在接黄萎病菌的量48h后明显上调，96h达到未接菌对照的5倍以上。GhsSUMO基因可受黄萎病菌诱导表达，表明该基因在陆地棉抗黄萎病的机制中可能发挥重要作用。

Cloning and Expression Analysis of GhSUMO Gene from Upland Cotton Inoculated with Vertieillium dahliae Kleb

As an important post-translational modification, sumoylation SUMO participates in a number of biological processes, including plant disease resistance, signal transduction and drought tolerance et al. Using an EST of a small ubiquitin-related modifier gene as the query probe to blast cotton EST database, a SUMO gene, with a complete open reading fragment （ORF） 396 bp encoding a protein of 95 amino acids, was successfully obtained in silico cloning and was named GhSUMO. The GhSUMO gene was verified by PCR amplifications using the cDNA and DNA templates from the root of upland cotton Yumian 21, which was of resistance to Verticillium wilt, and sequencing results showed that the GhSUMO had no intron. Sequence analysis showed that the protein has a conserved ubiqitin domain, the C-terminal double Gly fracture/Connection site, a conservative hydrophobic surface and an Ulpl-Smt3 interaction sites. Phylogenetic analysis showed the GhSUMO was highly identical with its ortholog from Ricinus communis, and the next most similar orthologs coming from other dicotyledons, but far away from monocotyledons. Quantitative PCR analysis showed that GhSUMO expression was significantly uprelated at the 48 h past innoculation with Verticillium dahliae, and the fold of relative gene expression at 96 h reached, more than 5 times. The induced expression of GhSUMO suggested that the gene may play important roles in the mechanism ofresitance to Verticillium wilt of upland cotton.