Genome-Wide Identification And Evolution Analysis Of The ARF Gene Family In Zea Mays L.

Auxin is an essential hormone in the process of plant growth, which plays an important role in various stages of plant development. In recent years, studies in signal transduction pathways and expression mechanisms of ARF genes in plants have become a hot issue. In this study, with bioinformation software, we perform structure analysis, phylogenetic analysis and expression analysis in ARF gene of maize whole genome, and the comparative analysis of ARF gene evolution between maize and other species are also performed. Comprehensive analysis of ARF gene family has important significance in studies of molecular cloning and evolution of ARF gene. The results are as follows:1. We perform search, comparison and selection in maize whole genome with various bioinformation software, a total of35different ARF genes are found. Integral comparative analysis of35ARF gene sequences shows that, the typical ARF gene contains three domains, namely N-terminal DNA binding domain (DBD), the middle of the core region (MR) and C-terminal dimerization domain (CTD)(domains III and IV). With reference to the naming method of rice ARF gene family, the ARF gene family of maize are named, respectively, ZmARF1-ZmARF35.2. Evolution relationship of ARF type genes is analysed with construction of phylogenetic tree, the results show that these genes are mainly distributed in four branches. Comparative analysis among ARF gene family of Arabidopsis, poplar, grape, rice and maize show that genes of maize and rice have high degree of homology, suggesting that the evolution of ARF type genes may be associated with differential separation evolution of monocot/sicot plants.3. The starting position of ARF type genes in chromosome is determined and its physical position of chromosome is mapped. The results show that35ARF genes distributed in ten chromosomes of maize dispersedly, and chromosome5has the largest number of6genes; chromosomes2,7,8,9have the smallest number of1gene, and there was no obvious phenomenon of gene cluster, which is consistent with chromosome position of other species reported.4. With structure analysis of maize ARFtype gene, gene structure of ARF gene which belongs to one category in evolutionary relationship is similar, and the number of intron and exon are the same; Homology analysis shows that the amino acid sequences, which compose the core region of ARF genes, has high similarity; Base sequence analysis shows that the structure of maize ARF type genes is complex, which contains20different motifs, motif1-8appear in the majority of maize ARF genes, and motif17,18,20appear in only a few genes. These genes with small number of motifs may play a significant role functionally.5. With maize EST databases, we analyse expression characteristics of35maize ARF genes, and all35genes have EST support. The results show that expression tissues of the maize ARF genes can be divided into7categories,28of which can expression specifically in one or more parts, but still there are7genes can not clearly predict the expression of specific parts of the organization, and only has expression information in mixed tissues. This expression pattern provides an important theoretical basis for in-depth study of the role and function of ARF.