Identification, bioinformatics analysis of LEA (Late embryogenesis abundant) genes in melon (Cucumis melo L.) and watermelon (Citrullus lanatus) and gene expression analysis under drought stress condition

LEAs which are late responsive genes, have important functions in response to various stress factors. Although genomes of melon and watermelon have been published, there is a little information about LEA gene family in these species. LEA gene family members in melon and watermelon species were examined in a comprehensive manner with bioinformatics tools. A total of 61 and 73 LEA genes have been identified in melon and watermelon, respectively. The highest orthologous genes rates were observed with melon and soybean (%63); watermelon and poplar (71%). The highest orthologous genes rates were observed with melon and soybean (%63); watermelon and poplar (71%). In silico conserved miRNAs analysis was preformed for two species. It was shown that 21 different CmLEA and ClLEA genes were targeted with 21 and 22 different miRNAs, respectively. Two species of transcriptome analysis was made from SRA databases. When compared to different melon varieties under salt stress condition, gene expression of CmLEA genes were generally up-regulated. Gene expression of ClLEA genes were significantly increased in phloem tissue rather than vascular tissue. Furthermore, gene expression levels of LEA gene family members including CmLEA 42, CmLEA 43 in melon and ClLEA 46, ClLEA 48 in watermelon were examined by Real Time PCR. Leaves and roots from two plant species under drought stress at 0, 3, 12 and 24 hours were sampled. Expression level of CmLEA 42 gene increased to 4 folds in the leaves (24th hours) and 1,5 folds in the roots (3rd hours). CmLEA 43 gene expression raised to 2,5 folds at 24th hours in leaves and 3 folds at 24th hours in roots. In watermelon, ClLEA 46 gene expression increased to 2,5 folds in the leaves (3rd hours) and 1,2 folds in the roots (12th hours). ClLEA 48 gene expression raised to 1,2 folds at 3rd hours in leaves and 1,5 folds at 24th hours in roots. This research may be a pioneer work for uncovering of drought- response mechanism in melons and watermelons and may provide a different perspective for the future studies.