苹果PDHB-1基因家族的鉴定与表达分析

Identification and expression analysis of apple PDHB-1 gene family

摘要:

丙酮酸脱氢酶E1组分β亚基-1 (pyruvate dehydrogenase E1 component subunit beta-1, PDHB-1)基因是编码丙酮酸脱氢酶复合物E1酶β亚基的基因，在果实酸度积累过程中具有重要作用。为了探究苹果(Malus domestica L.) PDHB-1家族的进化特征及其在不同酸含量苹果中的表达情况，本研究利用NCBI、Pfam等数据库和ClustalX、MEGA、TBtools等软件进行生物信息学分析，通过结合可滴定酸含量测定与实时荧光定量PCR (quantitative real-time PCR, qRT-PCR)分析，获得该家族基因在‘艾斯达’和‘成纪1号’ 2个不同酸含量的苹果中的表达情况。PDHB-1家族主要定位于叶绿体、细胞质和线粒体中，α-螺旋和不规则卷曲是该家族二级结构形成的主要因素。组织特异性表达谱显示大部分成员的表达量在果实中高于其他组织。qRT-PCR结果表明，大部分成员其表达量变化趋势与可滴定酸含量变化趋势一致，在果皮中，有14个成员的表达水平在酸含量较高的‘艾斯达’苹果中显著高于酸含量较低的‘成纪1号’，其中MdPDHB1-15差异最显著；在果肉中，17个成员的表达水平在‘艾斯达’苹果中显著高于‘成纪1号’，MdPDHB1-01表达量最高。预测苹果PDHB-1基因家族在苹果果实酸度积累过程中有重要调控作用。

Abstract:

Pyruvate dehydrogenase E1 component subunit beta-1 (PDHB-1) is a gene encoding the β-subunit of pyruvate dehydrogenase complex, which plays an important role in fruit acid accumulation. The aim of this study was to investigate the evolution characteristics of apple PDHB-1 family and its expression in apples with different acid contents. Bioinformatics analysis was performed using databases including NCBI, Pfam and software including ClustalX, MEGA, and TBtools. By combining titratable acid content determination and quantitative real-time PCR (qRT-PCR), the expression of this family genes in the peel and pulp of apple ‘Asda’ and ‘Chengji No.1’ with different acid content were obtained, respectively. The family members were mainly located in chloroplast, cytoplasm and mitochondria. α-helix and random coil were the main factors for the formation of secondary structure in this family. Tissue-specific expression profiles showed that the expression of most members were higher in fruit than in other tissues. qRT-PCR results showed that the expression profile of most members was consistent with the profile of titratable acid contents. In the peel, the expression levels of 14 members in ‘Asda’ apples with high acid content were significantly higher than that in ‘Chengji No.1’ apples with low acid content, where the expression difference of MdPDHB1-15 was the most significant. In the pulp, the expression levels of 17 members in ‘Asda’ apples were significantly higher than that in ‘Chengji No.1’ apples, where MdPDHB1-01 was the most highly expressed. It was predicted that PDHB-1 gene family in apple plays an important role in the regulation of fruit acidity.