title: High level of microsynteny and purifying selection affect the evolution of WRKY family in Gramineae.
abstract: The WRKY gene family, which encodes proteins in the regulation processes of diverse developmental stages, is one of the largest families of transcription factors in higher plants. In this study, by searching for interspecies gene colinearity (microsynteny) and dating the age distributions of duplicated genes, we found 35 chromosomal segments of subgroup I genes of WRKY family (WRKY I) in four Gramineae species (Brachypodium, rice, sorghum, and maize) formed eight orthologous groups. After a stepwise gene-by-gene reciprocal comparison of all the protein sequences in the WRKY I gene flanking areas, highly conserved regions of microsynteny were found in the four Gramineae species. Most gene pairs showed conserved orientation within syntenic genome regions. Furthermore, tandem duplication events played the leading role in gene expansion. Eventually, environmental selection pressure analysis indicated strong purifying selection for the WRKY I genes in Gramineae, which may have been followed by gene loss and rearrangement. The results presented in this study provide basic information of Gramineae WRKY I genes and form the foundation for future functional studies of these genes. High level of microsynteny in the four grass species provides further evidence that a large-scale genome duplication event predated speciation.
authors.affiliation: Key Laboratory of Crop Biology of Anhui Province, Collaborative Innovation Center of Anhui Grain Crops, Anhui Agricultural University, Hefei, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Jin
authors.affiliation: Key Laboratory of Crop Biology of Anhui Province, Collaborative Innovation Center of Anhui Grain Crops, Anhui Agricultural University, Hefei, China.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Kong
authors.affiliation: Key Laboratory of Crop Biology of Anhui Province, Collaborative Innovation Center of Anhui Grain Crops, Anhui Agricultural University, Hefei, China.
authors.forename: Jianle
authors.initials: J
authors.lastname: Qiu
authors.affiliation: Key Laboratory of Crop Biology of Anhui Province, Collaborative Innovation Center of Anhui Grain Crops, Anhui Agricultural University, Hefei, China.
authors.forename: Huasheng
authors.initials: H
authors.lastname: Zhu
authors.affiliation: Key Laboratory of Crop Biology of Anhui Province, Collaborative Innovation Center of Anhui Grain Crops, Anhui Agricultural University, Hefei, China.
authors.forename: Yuancheng
authors.initials: Y
authors.lastname: Peng
authors.affiliation: Key Laboratory of Crop Biology of Anhui Province, Collaborative Innovation Center of Anhui Grain Crops, Anhui Agricultural University, Hefei, China. hyjiang@ahau.edu.cn.
authors.forename: Haiyang
authors.initials: H
authors.lastname: Jiang
mesh_terms: D019143:Evolution, Molecular; D020440:Gene Duplication; D018745:Genome, Plant; D010940:Plant Proteins / Q000235:genetics*; D006109:Poaceae / Q000145:classification / Q000235:genetics*; D012641:Selection, Genetic; D026801:Synteny; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D010940:Plant Proteins; D014157:Transcription Factors
keywords: Gramineae; Microsynteny; Molecular evolution; WRKY Gene