Caicedo A L, Schaal B A, Kunkel B N
Department of Biology, Washington University, St. Louis, MO 63130, USA.
Proc Natl Acad Sci U S A. 1999 Jan 5;96(1):302-6. doi: 10.1073/pnas.96.1.302.
The RPS2 gene in Arabidopsis thaliana governs resistance to strains of the bacterial pathogen, Pseudomonas syringae pv. tomato, that express the avrRpt2 gene. The two loci are involved in a gene-for-gene interaction. Seventeen accessions of A. thaliana were sequenced to explore the diversity present in the coding region of the RPS2 locus. An unusually high level of nucleotide polymorphisms was found (1.26%), with nearly half of the observed polymorphisms resulting in amino acid changes in the RPS2 protein. Seven haplotypes (alleles) were identified and their evolutionary relationships deduced. Several of the alleles conferring resistance were found to be closely related, whereas susceptibility to disease was conferred by widely divergent alleles. The possibility of selection at the RPS2 locus is discussed.
拟南芥中的RPS2基因控制着对表达avrRpt2基因的番茄细菌性病原菌丁香假单胞菌菌株的抗性。这两个基因座参与了基因对基因的相互作用。对17个拟南芥种质进行了测序，以探索RPS2基因座编码区存在的多样性。发现了异常高水平的核苷酸多态性（1.26%），几乎一半观察到的多态性导致RPS2蛋白的氨基酸变化。鉴定出7种单倍型（等位基因）并推断了它们的进化关系。发现几个赋予抗性的等位基因密切相关，而对疾病的易感性则由差异很大的等位基因赋予。文中讨论了RPS2基因座发生选择的可能性。
