海岛棉几丁质酶基因GbCHI的克隆与功能分析

Cloning and functional analysis of chitinase gene GbCHI from sea-island cotton(Gossypium barbadense)

几丁质酶是植物主要的病程相关(PR)蛋白之一。前期工作中利用比较蛋白质组学方法,从海岛棉7124根部蛋白中分离到一个IV型几丁质酶(GbCHI)。文章通过同源克隆获得了海岛棉GbCHI基因的cDNA序列,并对该基因的表达特征及其蛋白的抑菌功能进行了分析鉴定。qRT-PCR实验结果表明GbCHI基因在棉花根、茎、叶、花和胚珠中均有表达,其表达受大丽轮枝菌、水杨酸(SA)、乙烯(ACC)和茉莉酸(JA)诱导;亚细胞定位分析显示GbCHI蛋白主要分布在细胞膜上;体外抑菌实验证明GbCHI蛋白能显著抑制大丽轮枝菌孢子的萌发和菌丝的生长。这些研究结果为了解GbCHI的功能及其在抗黄萎病棉花分子育种中的应用提供了实验依据和思路。

Chitinase is one of the important pathogenesis-related（PR） proteins in plants.By comparative proteomics study,a novel pathogen-responsive chitinase（known as GbCHI） has been identified from sea-island cotton（Gossypium barbadense）.The GbCHI cDNA was cloned from wilt-resistant sea-island cotton and the anti-fungal activity of the gene product was investigated.qRT-PCR analysis indicated that GbCHI was expressed constitutively in root,stem,leaf,flower,and ovule of cotton plant,and the expression could be induced by Verticillium dahliae and plant hormone SA,ACC,and JA.Subcellular localization analysis using GFP-tagged proteins showed that GbCHI-GFP fusion proteins were targeted mainly to the plasma membrane.Anti-fungal assay demonstrated that GbCHI could inhibit spore germination and hyphae growth of V.dahliae significantly.These results provide important information for understanding the cellular function of GbCHI and for exploring the application potential of this gene in molecular breeding of wilt-tolerant cotton plants.