龙眼胚性愈伤组织fw2.2家族2个基因的克隆与分析

Cloning and Sequence Analysis of Two Members of fw2.2 Gene Family from Embryogenic Callus in Dimocarpus longan Lour.

fruit weight 2.2(fw2.2)是植物中控制果实重量的重要数量性状的主效基因。以龙眼转录组数据库为基础,采用同源克隆法及RACE技术,从龙眼的胚性愈伤组织中获得fw2.2家族的2个cDNA全长序列,命名为Dlfw2.2-1与Dlfw2.2-1,并对其核甘酸序列及推导的氨基酸序列进行生物信息学分析。结果表明:Dlfw2.2-1基因的cDNA全长为970 bp,编码184个氨基酸;Dlfw2.2-2基因的cDNA全长为941 bp,编码175个氨基酸。Dlfw2.2-1与Dlfw2.2-2的核甘酸序列及其推导的氨基酸序列与其它植物的fw2.2具有较高的同源性,亚细胞定位于细胞质膜,不含信号肽,具有跨膜结构与典型的与PLAC8同源的富半胱氨酸蛋白(Cysteine-rich Protein)的保守结构域。植物中fw2.2系统进化树分析结果表明,Dlfw2.2-1和Dlfw2.2-2为同一分枝,与番茄和油梨的fw2.2的距离最近。因此,推测Dlfw2.2-1与Dlfw2.2-2属于fw2.2基因家族的2个成员。

fruit weight 2.2 （fw2.2） is an important quantitative trait locus （QTL） gene in controlling the fruit weight of plants. Based on the database of longan transcriptome, two members of fw2.2 family genes from longan embryogenic callus were obtained by the homologous cloning and RACE technology. They were named as Dlfw2.2-1 and Dlfw2.2-2, respectively. Bioinformatics ananlyses showed that the complete cDNA sequences of Dlfw2.2-1 were 970 bp, encoding 184 amino acids and the Dlfw2.2-2 were 941 bp, encoding 175 amino acids. Both the nucleotides and amino acids sequences of the two members were high homologous with those of the known fw2.2 genes in other species. Their proteins had no signal peptide, locating in the plasma membrane with transmembrane structure and the typical cysteine-rich protein domain. Phylogenetic tree analyses indicated that Dlfw2.2-1 and Dlfw2.2-2 belonged to the same branch with a close genetic relationship with Lycopersicon esculentum and Persea amer/cana.Therefore, the 2 members putatively belonged to the fw2.2 family.