柱型苹果MADS-box家族的2个同源基因克隆与生物信息学分析

Cloning and Bioinformatic Analysis of 2 Homologous Genes of MADS-box in Columnar Apple

基于笔者前期进行的柱型苹果转录组测序(RNA-seq)结果,采用RT-PCR方法,从柱型苹果花芽中克隆了MADS-box基因家族的2个同源基因,分别命名为MdSOCla和MdSOClb。分析结果表明,MdSOCla开放阅读框长度为708 bp,编码235个氨基酸,蛋白质分子量为26.95 kDa,等电点为9.13;MdSOClb开放阅读框长度为717 bp,编码238个氨基酸,蛋白质分子量为27.49 kDa,等电点为9.61。MdSOCla和MdSOClb的编码区碱基序列相似性为83.49%,氨基酸的相似性为73.72%。MdSOCla和MdSOClb的第1～75个氨基酸为高度保守的MADS盒结构域,第105～170个为K盒结构域。在构建的SOC1系统进化树中,MdSOCla与MdSOClb与苹果SOC1关系最近,其次为橙SOC1,与拟南芥SOC1同源基因进化关系最远。苹果、橙、大岩桐关系较近而聚为一类,而大豆、豇豆、葡萄、拟南芥、草莓和玉兰聚为一类。蛋白质二级结构预测显示,MdSOCla蛋白有8个α-螺旋,5个β折叠区,13个β-转角;而MdSOClb蛋白有11个α-螺旋,7个β折叠区,11个β-转角。推测二者在花的发育中可能起不同的调控作用。

Based on the results of previous study on columnar apple using RNA-seq technology,two full-length cDNA sequences of homologous gene of MADS-box from columnar apple were cloned by RT-PCR,which named as MdSOCla and MdSOClb. The MdSOCla contains an 708 bp open reading flame （ORF） corresponding to a deduced protein of 235 amino acids,while the estimated molecular weight and isoetectric point （pI） of the putative protein were 26.95 kDa and 9.13. The MdSOClb with an open reading flame （ORF） of 717 bp,encoding 238 amino acids with a predicted molecular mass of 27.49 kDa and a pI of 9.61. The identity of nucleotide between MdSOCla and MdSOClb was 83.49% ,and it was 73.72% was deduced amino acid sequence. The results indicated that MdSOCla and MdSOClb had 1 to 75 amino acids highly conserved MADS-box domain, 105 to 170 for the K-box domain. The phylogenetic tree of SOC1 showed that MdSOCla and MdSOClb were closest with apple SOC1, followed by orange SOC1 ,and the evolutionary relationships of homologous genes in Arabidopsis SOC1 was farthest. Apple, orange and sinningia were clustered together, while soybean, cowpea, grape,Arabidopsis thaliana, strawberries and magnolia were clustered to another group. Predicted protein secondary structure showed that MdSOCla protein had the structure with 8 or-helix,5 β-sheet region, 13 β-turn ;and MdSOClb protein had 11 or-helix,7 β-sheet region andl 1 β-turn. Those re- suits speculated that MdSOCla and MdSOClb played a different role in regulation in flower development.