Genetic and physical mapping of AvrPi7, a novel avirulence gene of Magnaporthe oryzae using physical position-ready markers  

作　　者：FENG ShuJie WANG Ling MA JunHong LIN Fei PAN QingHua 

机构地区：[1]Laboratory of Plant Resistance and Genetics, College of Natural Resources and Environmental Science, South China Agricultural University, Guangzhou 510642, China [2]Laboratory of Plant Protection, College of Horticulture, South China Agricultural University, Guangzhou 510642, China

出　　处：《Chinese Science Bulletin》2007年第7期903-911,共9页

基　　金：Supported by the National Basic Research Program of China (Grant No. 2006CB100206);the Program for Changjiang Scholars and Innovation Research Team in University (Grant No. IRT0448);the Natural Science Foundation of Guangdong Province (Grant Nos. 021006 and 039254)

摘　　要：Rice blast, caused by the fungal pathogen Magnaporthe oryzae, is one of the most devastating crop diseases worldwide. The avirulence gene corresponding to rice blast resistance gene Pi7 in field isolate CHL346 was inherited as a single gene, designated AvrPi7, in a segregating population consisting of 189 ascospore progenies derived from a cross between field isolates CHL346 and CHL42. In order to determine the chromosomal location of the AvrPi7 locus, a total of 121 simple sequence repeat (SSR) markers were developed based on the whole-genome sequence of reference isolate 70-15 of M. oryzae. Linkage analysis of the locus with these SSR markers showed that eight SSR markers on chromosome 1 were linked to the locus, among which the closest flanking markers MS1-9 and MS1-15 were 3.2 and 16.4 cM from the locus, respectively. For fine mapping, additional PCR-based makers including eight SSR markers and three candidate avirulence gene (CAG) markers were developed in the region flanking both markers. The AvrPi7 locus was genetically delimited within a 1.6-cM region flanked by markers MS1-21 and MS1-22, and co-segregated with the marker CAG2. To construct a physical map of the AvrPi7 locus, molecular markers linked to the Avr gene were mapped on the supercontigs of the ref-erence isolate 70-15 through bioinformation analysis (BIA). Consequently, the AvrPi7 locus was delim-ited to a 75-kb interval flanked by markers MS1-21 and MS1-22 based on the reference sequence. Merodiploids observed in this study are also discussed.Rice blast, caused by the fungal pathogen Magnaporthe oryzae, is one of the most devastating crop diseases worldwide. The avirulence gene corresponding to rice blast resistance gene Pi7 in field isolate CHL346 was inherited as a single gene, designated AvrPiT, in a segregating population consisting of 189 ascospore progenies derived from a cross between field isolates CHL346 and CHL42. In order to determine the chromosomal location of the AvrPi7 locus, a total of 121 simple sequence repeat （SSR） markers were developed based on the whole-genome sequence of reference isolate 70-15 of M. oryzae. Linkage analysis of the locus with these SSR markers showed that eight SSR markers on chromosome 1 were linked to the locus, among which the closest flanking markers MS1-9 and MS1-15 were 3.2 and 16.4 cM from the locus, respectively. For fine mapping, additional PCR-based makers including eight SSR markers and three candidate avirulence gene （CAG） markers were developed in the region flanking both markers. The AvrPi7 locus was genetically delimited within a 1.6-cM region flanked by markers MS1-21 and MS1-22, and co-segregated with the marker CAG2. To construct a physical map of the AvrPi7 locus, molecular markers linked to the Avr gene were mapped on the supercontigs of the reference isolate 70-15 through bioinformation analysis （BIA）. Consequently, the AvrPi7 locus was delimited to a 75-kb interval flanked by markers MS1-21 and MS1-22 based on the reference sequence. Merodiploids observed in this study are also discussed.

关 键 词：水稻 稻瘟病 梨孢真菌 无毒性基因 AvrPi7 遗传图谱 物理图谱 现成定位标记 

分 类 号：S435.111.41[农业科学—农业昆虫与害虫防治] S432.44[农业科学—植物保护]