摘要： 为深入研究CsamiR399b对黄瓜果实膨大的影响，对CsamiR399b及其靶基因CsUBC24进行生物信息学分析，并通过实时荧光定量PCR分析了CsamiR399b的表达特性。结果发现，CsamiR399b前体序列含有完整的茎环结构；CsamiR399b在膨大的黄瓜果实中表达量高于开花当天子房和未膨大子房，证实其参与黄瓜果实膨大调控。对靶基因的生物信息学分析发现，CsUBC24蛋白二级结构主要由无规则卷曲和α-螺旋构成，该蛋白质无信号肽及跨膜结构，定位于细胞核，为可溶性蛋白。系统进化树表明，黄瓜CsUBC24与甜瓜、南瓜和苦瓜等物种UBC24遗传距离较近；通过序列比对和保守域分析发现，各物种UBC24蛋白序列和功能结构域表现出较高的保守性，说明UBC蛋白功能保守。推测CsamiR399b通过调控CsUBC24基因表达参与了黄瓜果实膨大。

关键词: 黄瓜, 果实膨大, miR399b, 泛素结合酶24, 生物信息学分析

Abstract: In order to deeply understand the effect of CsamiR399b on cucumber fruit expansion, the bioinformatics analysis of CsamiR399b and its target gene CsUBC24 were carried out, and the expression characteristics of CsamiR399b was analyzed using qRT-PCR. The results showed that the CsamiR399b precursor sequence contained the complete stem-loop. CsamiR399b showed higher expression level in expanding fruit than in ovary(0 d)and unexpanding ovary, which proved that CsamiR399b involved in fruit expansion of cucumber. Bioinformatics analysis showed that the secondary structure of CsUBC24 protein was mainly composed of random curl and α-helix. CsUBC24 protein was a soluble protein without signal peptide and transmembrane structure, which might be located in the nucleus. Phylogenetic tree indicated that cucumber CsUBC24 shared highly similarity with UBC24 from melon, pumpkin and balsam pear. The sequence and functional domain of UBC24 protein among differential species were highly conserved based on the analysis of sequence alignment and conserved domain, which indicated the conserved function among differential species. The results suggested that CsamiR399b involved in fruit expansion of cucumber by regulating the expression of CsUBC24, which would provide a basis for further studying the function of CsamiR399b and its target gene CsUBC24 in cucumber fruit expansion.

Key words: Cucumber, Fruit expansion, miR399b, UBC24, Bioinformatics analysis

中图分类号: 

• S642.2