西瓜ζ-胡萝卜素脱氢酶基因ZDS的克隆和序列分析

Cloning and Sequence Analysis ofζ-Carotene Desaturase Gene from Watermelon(Citrullus lanatus L.)

西瓜果实因富含类胡萝卜素而具有一系列瓤色。为研究西瓜果实中类胡萝卜素合成过程,利用西瓜参考基因组数据,从红色西瓜材料LSW-177中克隆了一个ζ-胡萝卜素脱氢酶基因(ZDS)的cDNA全长,命名为ClZDS,该基因编码区为1731 bp,编码576个氨基酸。亚细胞定位预测显示,ClZDS蛋白可能被定位在叶绿体中;保守结构域和多重序列比对分析显示,西瓜ClZDS蛋白含有高等植物ζ-胡萝卜素脱氢酶特有的NAD结合结构域以及类胡萝卜素结合结构域;系统进化树分析表明ClZDS与同属葫芦科的甜瓜和西葫芦的ZDS蛋白亲缘关系最近,物种间分化程度较小;荧光定量PCR结果显示ClZDS基因在西瓜果实授粉后40 d表达量最高。这些结果为进一步研究ClZDS基因在西瓜果实的类胡萝卜素合成途径中的作用提供了依据。

Watermelon contains a complex source of carotenoids and exhibits a wide range of fruit colour.In order to investigate the carotenoids biosynthesis,the full-length ofζ-carotene desaturase gene,named ClZDS,had been cloned from the red-flesh watermelon LSW-177 based on the reference genome in Cucurbit Genomics Database.The result showed that the gene contained an ORF with 1731 bp,encoding 576 amino acids.The prediction of subcellular localization indicated that the ClZDS of watermelon was located in the chloroplast.Sequence alignment showed that the protein encoded by ClZDS in watermelon contain higher plant conserved NAD binding domains and carotenoids binding domain.The consistency of ClZDS and the proteins from Cucurbita melon and Cucurbita pepo were higher than others,indicating the closed genetic relationship in Cucurbitaceae.The qRT-PCR analysis showed that the expression of ClZDS was the highest at 40 DAP during watermelon fruit ripening.These results provided a basis for further research on the gene function in carotenoids biosynthesis during watermelon fruit ripening.