DNA polymorphism in the blast disease resistance gene Pita of the wild rice Oryza rufipogon and its related species
DNA polymorphism in the blast disease resistance gene Pita of the wild rice Oryza rufipogon and its related species
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DOI：
10.1266/ggs.84.121
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发表时间：
2009-04-01
影响因子：
1.1
通讯作者：
Miyashita, Naohiko T.
中科院分区：
文献类型：
--
作者：
Yoshida, Kentaro;Miyashita, Naohiko T.
本研究以野生稻(Oryza Rufipogon)、栽培稻(Oryza Rufipogon)以及两个近缘野生稻(Oryza meridionalis和O.Medicinalis)为材料，分析了抗稻瘟病基因PITA的种内和种间DNA变异，以阐明PITA在这些物种中的核苷酸多态维持机制和进化。普通野生稻(O.rufipogon Pita)沉默位点的核苷酸多样性为0.0101，相对于其他普通野生稻的核基因而言，这是一个中间值。在普通野生稻PITA区检测到核苷酸多态的二态现象。对稻瘟病菌的接种验证了稻瘟病菌PITA基因以二态序列类型存在。抗性PITA等位基因的变异水平低于敏感PITA等位基因。进化关系假说表明，导致抗性和敏感性差异的氨基酸突变发生在较近的时间。这些结果表明，抗性PITA来源于敏感的PITA。抗性和感病野生稻的亮氨酸富含结构域(LRD)替换位点的核苷酸多样性均较低。在中性性试验中，检测到的RRD值为显著负值。用纯化选择的方法解释了感病PITA基因LRD替换位点核苷酸多样性低的原因。比较药用野生稻和普通野生稻的PITA，发现在LRD中存在过量的非保守氨基酸替换，这可能与寄主-病原菌的相互作用有关。
Intra-and interspecific DNA variations in the blast resistance gene Pita in wild rice (Oryza rufipogon), cultivated rice (O. sativa), and two other related wild rice species (O. meridionalis and O. officinalis) were analyzed to elucidate the nucleotide polymorphism maintenance mechanisms and evolution of Pita in these species. Nucleotide diversity at silent sites of O. rufipogon Pita was 0.0101, an intermediate value relative to other O. rufipogon nuclear genes. A dimorphic pattern of nucleotide polymorphism was detected in the O. rufipogon Pita region. Inoculation of the blast fungus Magnaporthe oryzae verified that the O. rufipogon Pita gene resides in a dimorphic sequence type. The resistance Pita allele had lower levels of variation than the susceptibility pita allele. A hypothesis of evolutionary relationships indicated that the amino acid mutation in the O. rufipogon Pita protein responsible for the difference between resistance and susceptibility occurred relatively recently. These results suggested that the resistance Pita originated from the susceptibility pita. Nucleotide diversity at replacement sites of the leucine-rich domain (LRD) of both the resistance and susceptibility O. rufipogon pita was low. In tests of neutrality, significantly negative values were detected for the LRD of O. rufipogon susceptibility pita. The low nucleotide diversity at replacement sites of the LRD of the susceptibility pita could be explained by purifying selection. Comparison of Pita between O. rufipogon and O. officinalis revealed an excess of nonconservative amino acid substitutions in the LRD, which could be related to the host-pathogen interaction.