百日草几丁质酶基因片段克隆及其序列分析

目的]克隆百日草几丁质酶的基因片段,并对其序列进行分析.方法]以百日草“梦境”系列为材料,提取其叶片总RNA,并根据其他植物几丁质酶基因保守序列设计简并引物,通过RT-PCR克隆百日草几丁质酶基因片段（ZEchi）,并对该基因序列进行分析.结果]克隆得到的片段长度为227 bp,共编码75个氨基酸残基;核苷酸同源性分析表明,ZEchi与已报道的其他植物几丁质酶基因同源性达70％以上,其中与葡萄的同源性最高,为74％;氨基酸同源性分析表明,该几丁质酶多肽属于18家族几丁质酶,且与已报道的其他植物几丁质酶氨基酸序列具有70％以上的相似性;氨基酸聚类分析表明,该几丁质酶多肽与白车轴草和蒺藜苜蓿的几丁质酶聚类;生物信息学分析表明,由该基因片段编码的多肽为非跨膜蛋白,主要含α螺旋和随机线圈螺旋等二级结构.结论]该研究为进一步研究几丁质酶基因的功能奠定了基础.

Gene Cloning and Sequence Analysis of Chitinase Gene in Zinnia elegans

Objective] The aim was to clone and analyze the sequence of chitinase gene segment in Zinnia elegans.Method] Using the ＂ Dreamland＂ series of Z.elegans as materials,the total RNA of the leaves was extracted from.The degenerate primers were designed according to the conservative sequences of chitinase gene in other plants,and the chitinase gene segment of Z.elegans （ZEchi） was cloned by RT -PCR,and then the gene sequence was analyzed.Result] The cloned segment was 227 bp and encoded 75 amino acid residues; homology analysis of the nucleotides showed that the sequence of ZEchi had more than 70％ similarity with those of other reported plants＇ chitinase gene,and it had the highest homology with Vitis vinifera of 74％ ; homology analysis of the deduced amino acids showed that the chitinase polypeptide belonged to the 18 family chitinase and the sequence had more than 70％ similarity with those of other reported plants＇ chitinase ; amino acids cluster analysis showed that the chitinase polypeptide was clustered together with Trifolium repens and Medicago truncatula ; bioinformatics analysis showed that the polypeptide was not a transmembrane protein and mainly contained two secondary structure of alpha helix and random coil.Conclusion] The study laid a foundation for the further study on the function of chitinase gene.