Examination of the expansin gene family in melon and watermelon plants and gene expression profiles under different abiotic stress conditions

Watermelon (Citrullus lanatus) and melon (Cucumis melo) are plants that are considered economically important spread over a wide history. They are produced almost anywhere in our country. The expansin gene family is involved in cell growth and development in plants. Expansins are consisted of 4 subgroups: EXPA, EXPB, EXPLA and EXPLB. These proteins have a very important role for improvement tolerance to various stresses and plant development. In our study, expansin genes in watermelon and melon plant genomes were determined. A total of 40 genes on 11 chromosomes and 43 genes on 12 chromosomes were determined on watermelon and melon genomes, respectively. In addition, gene ontology analyses, detection of miRNAs targeting the expansin genes and gene orthologs in other plants of expansin genes were also performed. Besides, transcriptome data (RNA-seq) for both watermelon and melon were separately found in the relevant database. Then, advanced bioinformatics analyses were performed on these data and the genes to be studied in real-time PCR were selected depending on the increase in expression levels. To determine the expression levels of genes, ABA treatment, drought, heat, cold and salt stresses were firstly applied to the tissues of both plants and then tissues were collected at 0., 1., 3., 6., 12. and 24. hours after the stress applications. Then, the RNA isolation from tissues and cDNA synthesis were performed. The genes selected from the transcriptome data were examined by real-time PCR analysis. As a result of the analyzes, ClaEXPA-04, ClaEXPA-09, ClaEXPB-01, ClaEXPB-03 and ClaEXPLA-13 genes from watermelon and CmEXPA-10, CmEXPA-12 and CmEXPLA-01 genes from melon are considered to play a key role in plant tissue development and resistance to abiotic stress. Our study provides extensive information for understanding of functions of the expansin genes from watermelon and melon. It also provides a basis for studies on the stress tolerance of expansin genes under abiotic stress conditions. As a result, it is thought that this information will be benefit for watermelon and melon breeding studies. KEYWORDS:Cucumis melo, Citrullus lanatus, Expansin, Abiotic Stress, Gene Expression Analysis June 2022, 372 Pag