| Magnaporthe oryzae B.Couch is one of the most devastating diseases in rice production in the world.In order to prevent effectively rice blast in the long term,it is necessary to research deeply on the interaction regulation mechanism between rice and Magnaporthe oryzae,to understand the mechanism of the pathogen’s loss of avirulence and to elucidate the effect of avirulence gene mutations on rice resistance,providing a reliable theoretical basis for the control of rice blast.In the study,the AVR-Pita family genes,PWL family genes,AVR-Pib,AVR-Pik,Avr Piz-t,ACE1,AVR-Pi9,AVR-Pia,AVR-Pii and AVR1-CO39 gene sequences were used to design specific primers.PCR amplification and sequence analysis of 335 isolates of Magnaporthe oryzae from different regions of Heilongjiang Province in 2016 and 2017.The pathogenicity of rice blast isolates with different variation types was determined by rice resistant single gene lines.1.Identification of 15 avirulent genotypes of Magnaporthe oryzae in Heilongjiang Province.PCR amplification results showed that AVR-Pita1,AVR-Pita3,PWL2,PWL3,PWL4,AVR-Pib,AVR-Pik,Avr Piz-t,ACE1,AVR-Pi9,AVR-Pia and AVR-Pii were all distributed in Heilongjiang Province.Among them,the frequency of AVR-Pik was 87.16%.The frequency of PWL1,AVR-Pita2 and AVR1-CO39 were 0.2.The results of sequencing analysis of some strains with different bands showed that,five genotypes were detected in AVR pita1,AVR-Pita1(1,A,B,C,D),PWL2 detected 5 genotypes,PWL2(2,2-1,2-2,2-3,2-4),PWL3 detected 5 genotypes,PWL3(3,3-1,3-2,3-3,3-4),PWL4 detected 4 genotypes,PWL4(4,4-1,4-2,4-3),AVR-Pib detected 5 types of mutations,AVR-Pib(1-1,1-2,2,3,3-1),AVR-Pik detected 7 alleles,AVR-Pik(D,A,B,C,E,F,F2);Avr Piz-t detected 4 genotypes,Avr Piz-t(A,B,C,D),avirulence genes AVR-Pita3,ACE1,AVR-Pi9,AVR-Pia and AVR-Pii No mutant strain was found in the selected sequencing strains.3.The isolates of.AVR-Pita1(1,A,B,C,D),AVR-Pib(1-1,1-2,2,3,3-1),Avr Piz-t(A,B,C,D)were inoculated to the rice single gene lines IRBt La-kl(Pita1),BL1(Pib)and IRBLzt-T(Piz-t),the results showed that genotype AVR-Pita1(1,B,C,D),AVR-Pib,(1-1,1-2,2,3-1)and Avr Piz-t(B,C,D)avirulence loss of function. |
