Study On Correlation Between Pathotypes And DNA Fingerprinting Patterns Based On Virulence Gene Of Rice Blast Fungus

Rice blast disease is one of the major factors threatening high and stable production of rice. Nine pairs of specific primers of rice blast virulence genes were designed for PCR amplification, by which the 44 strains from different geographical regions were analyzed and their finger-printings were obtained. The pathogenicities of 31 strains were identified by using 18 LTH NILs, and the relationship between pathogenicity and fingerprinting was studied at the same time. The current study laid a foundation for studying the group structural variance of rice blast pathogenicity, which elucidated the relationship between genetic lineage and pathogenicty, and provided scientific information to transgenic breeding.â… . A specific fragment, whose length was similar to that of theoretic result, had been obtained by amplifying the fragment of virulence genes relate to 9 pairs of specific primers. But the fragment was not amplified in some strains. The strains could be classified into 8 types according to non-virulence genes and 6 types according to virulence genes. 54.5% of the strains belong to the some group in which the specific fragment could be amplified.â…¡. Clustering analysis was performed according to the resistance-susceptibility response of the 18 LTH NILs. All the 31 strains could be grouped to 7 pathotypes at the site of Lable Number 10.20 strains belonged to type H1, accounting for 64.5% of the whole strains, and the others belonged to types H2-H7 respectively.â…¢. The finger-printing classified according to specific primers of related virulence genes was not correlated with the pathotype classified according to resistance-susceptibility reaction of LTH NILs.â…£. The specific fragments in No. 8 strain were amplified with the specific primers relative to Avr-pita, PWL2, PWL3, MPG1, and were sequenced,blast.Results indicated that the 857th site of the specific fragment was mutated from G to A compared to the original fragment of PWL2, resulting in the change of amino acid at the 91st site from D to N. The single gene mutation was occurred at the 315th site of the specific fragment compared to the original fragment of PWL3, causing the change of amino acid at the 11th site from T toâ… . No change in MPG1. 11 bases of the Avr-pita fragment changed, causing the change of amino acids at 6 different sites(one of the 6 was inserted by 3 consecutive bases).