Cultural Characters, Pathogenicity And Genetic Diversity Analysis Of Magnaporthe Grisea And In Heilongjiang

Magnaporthe grisea is one of the major diseases of rice in Heilongjiang province. M.grisea causing the losses of yield accounted for about5%of the total one and reduced thequality of rice. The most cost-effective measures to prevent the disease were to use resistantcultivars. Resistant varieties usually lose resistance gradually after planting because of changesin the pathogenicity of fungus. It is very necessary to understand and grasp the toxicity structureand variation of the M. grisea in Heilongjiang provinve. This research collected and separatedthe M. grisea strains from20counties in Heilongjiang province in2013. Research the culturalcharacters, the ability to produce melanin, genetic diversity and pathogenicity, clearing aboutthe complexity of M. grisea in and around the differences of different zones in Heilongjiangprovince. This work would promote the cultivation of rice plant and control of M. grisea.The results can be generalized here:1. Reserach the cultural characters of88M. grisea strains on the PDA medium.Aerial mycelium of43.2%strains growed intensively, the backs of colonies of36.36%strainswere deep color and the shapes of the backs of colonies of55.68%strains. Cultural charactersof M. grisea were different in different regions. In addition, no correlation was observedbetween M. grisea growth rate and spore production capacity.2. The test surveyed the color of the backs of colonies of59M. grisea strains in Heilongjiangprovince and the color of colonies of72.9%strains were deep color. It suggested that the abilityto produce melanin of M. grisea in Heilongjiang province was greater. The test surveyedquantitative analysis of the ability to produce melanin of59M. grisea strains bycombine quantitative assay. There is a big difference in the amount of melanin among strains.Concentration of melanin differed by203.5times between the strongest and the weakest M.grisea strains. Correlation analysis showed that no significant concentration between amount ofmelanin and color of colonies. The ability to produce melanin of M. grisea strains fromcounties in Heilongjiang province was different by the geographic area. The stronger ability toproduce melanin of M. grisea strains was distributed in central and eastern regions inHeilongjiang province. There were significant differences in the ability to produce melanin ofdifferent M. grisea strains from the same place. 3.181M. strains can be divided into11genealogies based on11pairs of SSR primers at0.72levels. However,7specific lineages only have1-3strains. Strains collected from one zonecannot be categorized into one genealogy by cluster analysis.4. After challenged with90M. grisea strains, research pathogenicity of43major cultivationrice varieties in Heilongjiang province. These M. grisea strains showed complex pathogenicityand geographical difference. There is a big difference in pathogenicity of M. grisea strains ofdifferent zones. There were significant differences in pathogenicity of M. grisea strains fromthe same place. There were significant differences in toxicity of M. grisea strains of differentzones. Pathogenicity of most strains was more consistent by analysis of the pathogenic strain’sdendrogram Compared with genetic lineage of M. grisea strains, no correlation can be observedbetween genealogy and pathogenicity.