Genome-wide characterisation of superoxide dismutase genes in grape and their expression analyses during berry development process

Previous studies about superoxide dismutase (SOD) genes were mostly with regard to biotic and abiotic stress responses. Some reports have indicated SOD genes may play an important role in plant development. However, little is known about the relationship of SOD genes with grape berry ripening. Thirteen VviSOD genes were identified from grape genome sequences based on the bioinformatic method. Phylogenetic analysis indicated that these VviSODs could be divided into two groups. The genes of VviCu/ZnSOD1a and VviCu/ZnSOD1c were identified as tandem replication genes. The expression analyses based on RNA-Seq and qRT-PCR results in ‘Kyoho’ and its early-ripening bud mutant, ‘Fengzao’, demonstrated that the VviSOD genes involved in the grape berry ripening and VviCu/ZnSOD1c were the main candidate. Sequence analysis of VviCu/ZnSOD1c gene in ‘Fengzao’ showed that the coding sequence was the same as that of ‘Kyoho’. According to the bioinformatic and expression analysis, VviSOD genes probably involved in the grape berry ripening and VviCu/ZnSOD1c was selected as the main candidate to further explore its potential role in the early ripening of ‘Fengzao’.此前针对超氧化物歧化酶（superoxide dismutase, SOD）基因的相关研究多聚焦于生物与非生物胁迫应答过程。已有部分研究表明，SOD基因在植物生长发育中发挥重要调控作用。然而，目前学界对SOD基因与葡萄果实成熟之间的关联仍知之甚少。本研究通过生物信息学方法从葡萄基因组序列中鉴定得到13个VviSOD基因。系统进化分析结果显示，上述VviSOD基因可划分为两个类群。其中VviCu/ZnSOD1a与VviCu/ZnSOD1c被鉴定为串联重复基因。基于‘巨峰’（Kyoho）及其早熟芽变品种‘早丰’（Fengzao）的RNA测序（RNA-Seq）与实时荧光定量聚合酶链式反应（qRT-PCR）表达分析结果证实，部分VviSOD基因参与葡萄果实成熟调控，其中VviCu/ZnSOD1c为核心候选基因。对‘早丰’材料中VviCu/ZnSOD1c基因的序列分析表明，其编码序列与‘巨峰’完全一致。综合生物信息学与表达分析结果，本研究推测VviSOD基因参与葡萄果实成熟过程，并选定VviCu/ZnSOD1c作为核心候选基因，以进一步解析其在‘早丰’早熟特性中的潜在作用。