云南稻瘟病菌系谱与致病型的关系

Relationship Between Genetic Lineage and Pathotype of Pyricularia grisea in Yunnan Plateau

为探究稻瘟病菌无性世代DNA水平的变异 ,寻找云南稻瘟病菌谱系 (geneticlineage ,G)和致病型之间的对应关系 ,根据稻瘟病菌散布的重复序列Pot2 (Pyriculariaoryzaetransposon) ,对云南水稻主产区稻瘟病菌菌株DNA进行了rep PCR(repetitivepolymerasechainreaction)扩增 ,获得rep PCR指纹。聚类分析将 134个稻瘟病菌代表菌株划分为G1～G8等 8个谱系 ,揭示云南水稻主产区稻瘟病菌无性系丰富的遗传多样性。进一步接种分析了8个谱系的 2 9个稻瘟病菌菌株对 33个云南主产区水稻品种的亲和性 ,依其毒性谱 ,采用STATISTICAL 5 0软件的UPGMA程序进行聚类分析 ,将其划分为P1～P6等 6个致病型群 (pathotypegroup)。结果表明同一谱系的稻瘟病菌菌株多数对应 2～ 3个致病型群 ,少数 1个或 4个致病型群 ;但G1～G8等 8个谱系中的部分菌株都可对应致病型群P2。因此 ,云南水稻主产区稻瘟病菌谱系和致病型群之间属于复杂关系类型。此外 ,33个水稻品种中的合系 16和京国 92抗全部 2 9个稻瘟病菌株 ,云粳 2 0和合系 30对全部供试菌株表现感病 ,这对云南水稻主产区品种布局提供了稻瘟病抗性方面的依据。因此 ,从育种应用和生产实际需要出发 ,水稻品种抗瘟谱测定仍然必要。

Rice blast caused by Pyricularia grisea is the most destructive disease in Yunnan Plateau,China.In order to elucidate the relationship between genetic lineage and pathotype of P.grisea of Yunnan Plateau as well as the variability of the fungus at DNA level,the repetitive element-based PCR (rep-PCR) of Pot2,an element found in approximately 100 copies in the fungus genome,was exploited.Two hundred and thirty-six isolates of P.grisea collected from 15 main rice-growing counties of Yunnan Plateau were fingerprinted by using rep-PCR.A linkage graph of the rep-PCR fingerprints from 134 representative isolates was generated using an unweighted pair-grouped average program (UPGMA) of the STATISTICAL 5.0 software.The isolates were classified into 8 genetic lineages (G1～G8) at the level of 1.75 genetic linkage distance,of which the G1,G2 and G4 were the dominant lineages.The isolates in a certain area generally belonged to one correspondent genetic lineage and the isolates from the same plot and host rice variety mostly shared one linkage group though different genetic lineages within one lesion.Furthermore,29 isolates representing the eight genetic lineages were inoculated on 33 rice cultivars of Yunnan at the stage of 3～4 leaves in greenhouse.The isolates were divided into 6 pathotype groups (P1～P6) according to its compatibility,which demonstrated that some isolates of one genetic lineage sharing two or three pathotype groups,alternatively,one or four pathotype groups.The isolates from each genetic lineage,however,may share one pathotype group such as P2.The preliminary results implicated that the relationship between genetic lineages and pathotype groups of P.grisea in Yunnan Plateau was complicated rather than simple.On the other hand,2 rice cultivars including HeXi 16 and JingGuo 92 were resistant to the 29 isolates but YunJing 20 and HeXi 30 both susceptible to all of them,which was helpful for deploying the blast-resistant genes in rice production of Yunnan Plateau.Therefore,the rice blast-resistance spectrum of the tentative new rice cultivars should be evaluated before its release considering the blast-resistant rice breeding and the practice of rice production in Yunnan Plateau.