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与Pi-ta~-等位基因相比,含有Pi-ta~+等位基因的栽培稻具有抗稻瘟病特性。本研究用基因序列分析的方法检测了来自云南的不同栽培稻品种以及不同类型和来源的普通野生稻种和非洲长雄蕊野生稻种中的Pi-ta基因,发现Pi-ta基因在稻属植物中高度保守,但Pi-ta~+等位基因的存在极其稀有。在所检测的栽培稻和野生稻中仅有来源于云南景洪的直立型普通野生稻中含有Pi-ta~+等位基因。而与Pi-ta基因相比,另一个水稻抗稻瘟病基因Pib,经部分同源序列克隆及测序发现该基因在不同野生稻中的变异较大。在所克隆的不同野生稻Pib基因同源序列中,也只有来源于直立型普通野生稻的序列能按该基因的开放阅读框进行正常翻译。对不同类型普通野生稻的抗稻瘟病能力的初步鉴定结果表明,直立型普通野生稻对供试的本地稻瘟病生理小种具有较强抗性,其抗性可能源于所含的Pi-ta~+等位基因及可能有功能的Pib基因。由于普通野生稻与栽培稻同属AA基因组型,因此,云南直立型普通野生稻可通过杂交育种或基因工程途径用于栽培稻的抗稻瘟病性能改良。
Compared with Pi-ta ~ - allele, cultivated rice containing Pi-ta ~ + alleles had blast resistance. In this study, we detected the Pi-ta genes of different cultivated rice varieties from Yunnan, as well as the wild type and long-stalk wild rice varieties of different types and origins by gene sequence analysis. Highly conserved, but the presence of the Pi-ta ~ + allele is extremely rare. Among the cultivated rice and wild rice tested, only Oryza sativa originating from Jinghong of Yunnan Province contained Pi-ta ~ + alleles. Compared with the Pi-ta gene, another rice blast resistance gene Pib, cloned and sequenced by partial homologous sequences, found that the gene has a great variation in different wild rice varieties. Among the cloned Pib homologous sequences of different wild rice species, only the sequence from Oryza rufipogon can be transcribed according to the open reading frame of the gene. Preliminary identification of the blast resistance ability of different types of wild Oryza rufipogon (Oryza sativa) showed that upright Oryza rufipogal (Oryza rufipogon) had strong resistance to local rice blast physiological races tested, and its resistance might originated from Pi-ta ~ + Alleles and possibly functional Pib genes. Because common wild rice and cultivated rice belong to the same genotype of AA, Yunnan upright common wild rice can be used for improvement of rice blast resistance by means of cross breeding or genetic engineering.