Genome-wide identification and expression analysis of the cucumber <i>PYL</i> gene family

Abstract

Abscisic acid (ABA) is a very important hormone in plants. It regulates growth and development of plants and plays an important role in biotic and abiotic stresses. The Pyrabactin resistance 1-like (PYR/PYL) proteins play a central role in ABA signal transduction pathways. The working system of <i>PYL</i> genes in cucumber, an important economical vegetable (<i>Cucumis sativus</i> L.), has not been fully studied yet. Through bioinformatics, a total of 14 individual <i>PYL</i> genes were identified in Chinese long '9930' cucumber. Fourteen <i>PYL</i> genes were distributed on six chromosomes of cucumber, and their encoded proteins predicted to be distributed in cytoplasm and nucleus. Based on the phylogenetic analysis, the <i>PYL</i> genes of cucumber, <i>Arabidopsis</i>, rice, apple, <i>Brachypodium distachyon</i> and soybeancould be classified into three groups. Genetic structures and conserved domains analysis revealed that <i>CsPYL</i> genes in the same group have similar exons and conserved domains. By predicting cis-elements in the promoters, we found that all <i>CsPYL</i> members contained hormone and stress-related elements. Additionally, the expression patterns of <i>CsPYL</i> genes were specific in tissues. Finally, we further examined the expression of 14 <i>CsPYL</i> genes under ABA, PEG, salt stress. The qRT-PCR results showed that most <i>PYL</i> gene expression levels were up-regulated. Furthermore, with different treatments about 3h, the relative expression of <i>PYL8</i> was up-regulated and more than 20 times higher than 0h. It indicated that this gene may play an important role in abiotic stress.