SUPEROXIDE DISMUTASE FAMILY GENES IN WATERMELON AND THEIR RESPONSES TO DIFFERENT ABIOTIC STRESSES

Abstract

<List> <ListItem><ItemContent><p>• A total of 8 SOD genes from watermelon were identified and bioinformatically analyzed.</p></ItemContent></ListItem> <ListItem><ItemContent><p>• The SOD proteins from watermelon and other different plant species can be classified into five groups consistent with their metal cofactors.</p></ItemContent></ListItem> <ListItem><ItemContent><p>• ClSOD genes exhibited distinctive tissue-specific and abiotic stress responsive expression patterns.</p></ItemContent></ListItem></List></p> <p>Superoxide dismutase (SOD) is an important enzyme in the antioxidant system of plants and plays a vital role in stress responses by maintaining the dynamic balance of reactive oxygen species (ROS) concentrations. Genome-wide analysis of the SOD gene family in various plant species has been conducted but little is known about this gene family in watermelon (Citrullus lanatus). Here, eight SOD genes were identified in the watermelon genome and are designated ClCSD1-5, ClFSD1-2 and ClMSD according to their metal cofactors. Phylogenetic analysis shows that SOD proteins from various plant species can be classified into five groups and members in the same group possess the same metal cofactor and similar subcellular localizations. Expression analysis of the ClSOD genes indicates that they had tissue-specific expression patterns with high expression in different tissues including the leaves, flowers and fruit. In addition, the expression of ClSOD genes differed appreciably under salinity, drought and abscisic acid (ABA) treatments, indicating that they may be involved in ROS scavenging under different abiotic stresses via an ABA-dependent signaling pathway. These results lay the foundation for elucidating the function of ClSOD genes in stress tolerance and fruit development in watermelon.

Keywords

• abiotic stress|expression analysis|phylogeny|sod|superoxide dismutase|watermelon