Genome-wide analysis of the mitogen-activated protein kinase gene family in Solanum lycopersicum

Mitogen-activated protein kinases (MAPKs), a family of Ser/Thr protein kinases, play an essential role in mediating biotic and abiotic stress responses in plants. In this study, we investigated 16 putative SIMAPK genes from tomato genome and compared them with those from Arabidopsis. The full cDNA sequences of 13 novel SIMAPKs in tomato were obtained through PCR ampilification. A comprehensive genome-wide analysis of SIMAPKs in tomato is presented, including their gene structure, phylogeny, genome localization, and expression profiles. Phylogenic analysis of the 16 SIMAPKs and 20 AtMAPKs from Arabidopsis indicated that the SIMAPK genes were clustered into four major groups, and genes within the same groups had similar exon-intron structures. All SIMAPK proteins in groups A, B and C had a Thr-Glu-Tyr (TEY) activation domain, whereas those in group D contained a Thr-Asp-Tyr (TDY) activation domain. The analysis of 5'-upstream region of SIMAPKs revealed a group of putative cis-acting elements related to stress responses. Expression analysis of SIMAPIC genes using RT-PCR and real-time quantitative PCR demonstrated that all SIMAPK transcripts were able to be detected in at least one investigated tissue, and some of them exhibited tissue-specific expression patterns. The transcript abundance of nearly all SIMAPK genes was increased in response to heat stress treatment. Our data provided an insight into the evolution of the gene family and a useful reference for further functional analysis of MAPK family genes in tomato. (C) 2012 Elsevier B.V. All rights reserved.