Identification And Expression Analysis Of Myb Transcription Factors In Solanum Lycopersicum

In recent years, studies on transcription factors have been paying a great deal of attention in the fields of plant molecular biology and molecular genetics. The MYB class of transcription factors, which was one of the largest families in plant, attracted more and more attention. The MYB transcription factors are also known as transacting factors, which are characterized by a highly conserved DNA-binding domain-MYB motif. MYB transcription factors generally existed in plants and involved in growth and metabolism regulation, such as cellular morphogenesis, secondary metabolism and response to biotic and abiotic stresses. The tomato is not only a vegetable widely grown worldwide, but also one of the model studied plants. At present, little is available about MYB transcription factors function in tomato. Recently, the complete of tomato genome sequencing and database establishment provide an opportunity for genome-wide analysis of MYB transcription factors.In our studies, the candidate tomato MYB transcription factors were retrieved using amino acid sequence of Arabidopsis MYB transcription factor as query in the SGN database (http://solgenomics.net/). The candidate MYB transcription factors were further identified by the Pfam database (http://pfam.janelia.org/). Evolutionary relationships of these MYB transcription factors were revealed by constructing phylogenetic tree, which was generated from alignments of the protein sequences of tomato MYB genes. Finally, the expression patterns of selected tomato MYB genes were analyzed by quantitative real-time PCR (qRT-PCR) in the different tissues and under the different abiotic stresses. All these results are as follows:1We initially surveyed the SGN database (http://solgenomics.net) using the amino acid sequences of the conserved MYB domains from the known Arabidopsis MYB family members and tomato MYB members. Then, the candidate genes were identified by Pfam database. In all, we identified139members of tomato MYB family.2A comprehensive analysis of this gene family is presented, including ORF (Open reading frame), chromosome locations, and gene structures. In addition, multiple-sequence alignments were performed using the program ClustalX1.83. Phylogenetic analysis was carried out using MEGA5.0program. These genes were grouped into three subgroups:MYB-related (37members), R2R3-MYB (100members), and3R-MYB (2members). No member related4R-MYB was found in this study based on classification criteria from Arabidopsis MYB transcription factors. R2R3-MYB and MYB-related subfamilies were further grouped into32and5clades, respectively. 3To reveal the putative functions of some tomato MYB genes, the expression patterns were analyzed by qRT-PCR in fruit with different colors (green, purple, yellow and red), under different stress conditions (low temperature, high temperature, salt and drought), and under different hormone treatment conditions (ABA, BAP, NAA, SA, JA and GA3), and in different tissues (root, stem and leaf). The result showed that tomato MYB genes involved in multiple cellular processes. Among them, expression level of S1MYB133was significantly higher in the purple fruit than the green, red, yellow, suggesting that the gene may be involved in purple fruit metabolic reactions. Expression levels of seven tomato MYB genes are significant changes after stresses and hormone treatment conditions, indicating that these genes maybe involved in environmental stresses. In different tissues, expression levels of some genes were unstable, such as S1MYB89and S1MYB24.