[Genetic diversity of AVR-pita alleles of rice blast fungus Magnaporthe grisea].
Rice blast, caused by fungus Magnaporthe grisea, is one of the most serious diseases of rice throughout the world and is also a classical system in which avirulence (AVR) genes in the pathogen show a functional correspondence with particular resistance (R) genes in rice. The interaction between AVR-pita gene in Magnaporthe grsiea and Pi-ta gene in rice is a classical gene-for-gene system. The genetic diversity of AVR-pita alleles was showed by 44 isolates from the fields in Sichuan and Chongqing. According to the published sequence of AVR-pita (GenBank Accession No. AF207841), the special primers were designed and a population analysis of AVR-pita occurrence in the field was conducted. The PCR negative isolates did not trigger host resistance responses and the disease might occur. The positive special PCR band in an isolate was not corresponding with its avirulence to the Pi-ta rice line. Among 11 sequenced A VR-pita alleles, six AVR-pita alleles encoded the same protein, four proteins differed from each other by one amino acid and one had nonsense mutation. The strategy of utilizing Pi-ta in rice breeding was also discussed.
Ma
Bing Tian
BT
Rice Research Institute, Sichuan Agricultural University, Chengdu 611130, China. btma02@vip.sina.com
Qu
Guang Lin
GL
Shi
Jun
J
Chen
De Xi
DX
Lin
Yu Fan
YF
Huang
Wen Juan
WJ
Li
Shi Gui
SG
D005800:Genes, Fungal / Q000235:genetics*; D014644:Genetic Variation / Q000235:genetics*; D020082:Magnaporthe / Q000235:genetics* / Q000472:pathogenicity*; D012275:Oryza / Q000382:microbiology*; D010935:Plant Diseases / Q000382:microbiology; D016133:Polymerase Chain Reaction