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

Previous studies about superoxide dismutase (<i>SOD</i>) genes were mostly with regard to biotic and abiotic stress responses. Some reports have indicated <i>SOD</i> genes may play an important role in plant development. However, little is known about the relationship of <i>SOD</i> genes with grape berry ripening. Thirteen <i>VviSOD</i> 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 <i>VviCu/ZnSOD1a</i> and <i>VviCu/ZnSOD1c</i> 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 <i>VviSOD</i> genes involved in the grape berry ripening and <i>VviCu/ZnSOD1c</i> were the main candidate. Sequence analysis of <i>VviCu/ZnSOD1c</i> gene in ‘Fengzao’ showed that the coding sequence was the same as that of ‘Kyoho’. According to the bioinformatic and expression analysis, <i>VviSOD</i> genes probably involved in the grape berry ripening and <i>VviCu/ZnSOD1c</i> was selected as the main candidate to further explore its potential role in the early ripening of ‘Fengzao’.