title: Unraveling the evolution and regulation of the alternative oxidase gene family in plants.
abstract: Alternative oxidase (AOX) is a diiron carboxylate protein present in all plants examined to date that couples the oxidation of ubiquinol with the reduction of oxygen to water. The predominant structure of AOX genes is four exons interrupted by three introns. In this study, by analyzing the genomic sequences of genes from different plant species, we deduced that intron/exon loss/gain and deletion of fragments are the major mechanisms responsible for the generation and evolution of AOX paralogous genes. Integrating gene duplication and structural information with expression profiles for various AOXs revealed that tandem duplication/block duplication contributed greatly to the generation and maintenance of the AOX gene family. Notably, the expression profiles based on public microarray database showed highly diverse expression patterns among AOX members in different developmental stages and tissues and that both orthologous and paralogous genes did not have the same expression profiles due to their divergence in regulatory regions. Comparative analysis of genes in six plant species under various perturbations indicated a large number of protein kinases, transcription factors and antioxidant enzymes are co-expressed with AOX. Of these, four sets of transcription factors--WRKY, NAC, bZIP and MYB--are likely involved in the regulating the differential responses of AOX1 genes to specific stresses. Furthermore, divergence of AOX1 and AOX2 subfamilies in regulation might be the main reason for their differential stress responses.
authors.affiliation: Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, State Key Laboratory of Hydraulics and Mountain River Engineering, College of Life Science, Sichuan University, Chengdu, 610064, China.
authors.forename: Xiao-jun
authors.initials: XJ
authors.lastname: Pu
authors.affiliation: Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, State Key Laboratory of Hydraulics and Mountain River Engineering, College of Life Science, Sichuan University, Chengdu, 610064, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Lv
authors.affiliation: Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, State Key Laboratory of Hydraulics and Mountain River Engineering, College of Life Science, Sichuan University, Chengdu, 610064, China. hhlin@scu.edu.cn.
authors.forename: Hong-hui
authors.initials: HH
authors.lastname: Lin
mesh_terms: D019143:Evolution, Molecular; D005091:Exons; D020440:Gene Duplication; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D007438:Introns; D024101:Mitochondrial Proteins / Q000145:classification / Q000235:genetics*; D008957:Models, Genetic; D005810:Multigene Family; D010088:Oxidoreductases / Q000145:classification / Q000235:genetics*; D010802:Phylogeny; D010940:Plant Proteins / Q000145:classification / Q000235:genetics*; D010944:Plants / Q000145:classification / Q000201:enzymology / Q000235:genetics*; D000099188:Alternative Oxidase
chemical_list: D024101:Mitochondrial Proteins; D010088:Oxidoreductases; D010940:Plant Proteins; D000099188:Alternative Oxidase
keywords: Alternative oxidase loss of intron exon shuffling tandem gene duplication; Co-expression; Co-regulation