This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 140/3/998    most recent pp.105.073080v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via ISI Web of Science (9) Citing Articles via Google Scholar Google Scholar Articles by Sun, X. Articles by Wang, S. Search for Related Content PubMed PubMed Citation Articles by Sun, X. Articles by Wang, S. Agricola Articles by Sun, X. Articles by Wang, S.

GENETICS, GENOMICS, AND MOLECULAR EVOLUTION

Point Mutations with Positive Selection Were a Major Force during the Evolution of a Receptor-Kinase Resistance Gene Family of Rice^1,[W]

National Key Laboratory of Crop Genetic Improvement, National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan 430070, China

The rice (Oryza sativa) Xa26 gene, which confers resistance to bacterial blight disease and encodes a leucine-rich repeat (LRR) receptor kinase, resides at a locus clustered with tandem homologous genes. To investigate the evolution of this family, four haplotypes from the two subspecies of rice, indica and japonica, were analyzed. Comparative sequence analysis of 34 genes of 10 types of paralogs of the family revealed haplotype polymorphisms and pronounced paralog diversity. The orthologs in different haplotypes were more similar than the paralogs in the same haplotype. At least five types of paralogs were formed before the separation of indica and japonica subspecies. Only 7% of amino acid sites were detected to be under positive selection, which occurred in the extracytoplasmic domain. Approximately 74% of the positively selected sites were solvent-exposed amino acid residues of the LRR domain that have been proposed to be involved in pathogen recognition, and 73% of the hypervariable sites detected in the LRR domain were subject to positive selection. The family is formed by tandem duplication followed by diversification through recombination, deletion, and point mutation. Most variation among genes in the family is caused by point mutations and positive selection.

The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Shiping Wang (swang{at}mail.hzau.edu.cn).

^[W] The online version of this article contains Web-only data.

Article, publication date, and citation information can be found at www.plantphysiol.org/cgi/doi/10.1104/pp.105.073080.

^* Corresponding author; e-mail swang{at}mail.hzau.edu.cn; fax 86–27–87287092.

Received October 18, 2005; returned for revision January 10, 2006; accepted January 23, 2006.