桃Ⅱ型NADH脱氢酶家族基因鉴定和表达分析

Identification and expression analysis of the type Ⅱ NADH dehydrogenase family genes in peach

Ⅱ型烟酰胺腺嘌呤二核苷酸脱氢酶(TypeⅡNADH dehydrogenase)在所有已全基因组测序的植物中均存在,具有多种功能,尤其在大多数植物呼吸链中起重要作用。本研究对桃Ⅱ型NADH脱氢酶家族基因进行了鉴定,确定了桃Ⅱ型NADH脱氢酶基因家族成员数目、亚家族分类,并分别进行了克隆,同时分析了它的进化关系、在基因组骨架上分布、启动子区域、基因结构、不同组织表达水平及其编码的蛋白质结构。结果显示,桃Ⅱ型NADH脱氢酶基因家族共有6个成员,分布在3~6号染色体上,被分为3个亚家族:NDA、NDB、NDC。桃Ⅱ型NADH脱氢酶家族成员,脂肪族氨基酸指数范围是80.63~95.75,等电点预测结果表明Prupe.3G231400.1和Prupe.5G076700.1是酸性蛋白质,其余4个是碱性蛋白质;NDA和NDC亚家族成员二级结构均以无规则卷曲为主要构成元件,NDB亚家族成员二级结构均以α-螺旋为主要构成元件。Ⅱ型NADH脱氢酶家族基因在桃不同组织中的表达水平差异较大,5个基因在老叶中表达量相对较高,在成熟果肉中表达量低。这些结果为下一步进行Ⅱ型NADH脱氢酶基因功能验证奠定了重要基础。

Type Ⅱ nicotinamide adenine dinucleotide dehydrogenase(type Ⅱ NADH dehydrogenase) exists in all plants that have been sequenced by the whole genome and has a variety of functions, especially plays an important role in the respiratory chains of most plants. Type Ⅱ NADH dehydrogenase family genes were identified in this study, and the number of member and subfamily classification were determined. At the same time, the phylogenetic relationship, the distribution on the scaffold, promoter region, gene structure, expression levels in different tissues and encoded protein structure were analyzed. The results showed that type Ⅱ NADH dehydrogenase gene family in peach contained six members, which were located on the chromosome 3-6 and clustered into three subfamilies: NDA, NDB and NDC. All members of peach type Ⅱ NADH dehydrogenase family were stable amphoteric proteins, and the aliphatic amino acid index ranged from 80.63 to 95.75. The isoelectric point prediction results showed that Prupe.3 G231400.1 and Prupe.5 G076700.1 were acidic proteins, and the other four were basic proteins. The secondary structure of NDA and NDC subfamily members was mainly composed of random coil, while α-helix was the main component for the secondary structure of NDB subfamily members. The expression levels of type Ⅱ NADH dehydrogenase family genes in different tissues of peach were quite different. Among them, the expression levels of five genes were relatively high in old leaves and low in mature flesh. These results lay an important foundation for the functional verification of type Ⅱ NADH dehydrogenase gene in the future.