| Rice blast is one of the most devastating diseases in the production of rice. Currently,The most effective defense way is to improve the resistance of rice to Magnaporthe oryzae. The improve of host-plant resistance makes rice resist the disease by itself.The variation of population structure in rice blast fungus, however, is so complex that the resistant varieties just can be maintained by 2-3 years. we need still look for the new disease resistance genes and enlarge the reserves of disease resistance genes to adjust the different rice blast fungus. So, it is basic and core of cultivating disease resistant varieties that studying the pathogenicity rule of the rice blast fungus to rice and finding the new disease resistance genes. We collected 42 Magnaporthe oryzae from indica area and 16 Magnaporthe oryzae from japonica area as strains,to research the pathogenicity of Magnaporthe oryzae from different area to indica ZYQ8 and japonica JX17.We make use of DH population which are the posterity of indica ZYQ8 and japonica JX17 as mapping population.we locate the disease resistance genes which are different in indica and japonica to clone the new resistance genes. It can provide the basis for effective cultivation of resistant varieties. At the same time, we combine the result of Indica and japonica DH population genetic map to locate the disease resistance genes. It can provide the basis for finding and cloning the disease resistance genes.Results are as follows:1?The average sporulation of Magnaporthe strains from indica area is 27625 per ml, The average sporulation of Magnaporthe strains from japonica area is 28750 per ml. So we can know that the sporulation is consistent. The average spore germination rate of Magnaporthe strains from indica area is 43%. The average spore germination rate of Magnaporthe strains from japonica area is 35%. So the spore germination rate of the strains from indica area is better than the strains from japonica area.2?51 Magnaporthe oryzae which the sporulation are over 7000 per ml, In 37 Magnaporthe oryzae from indica area,19 Magnaporthe oryzae are susceptible to ZYQ8, 19 Magnaporthe oryzae are susceptible to JX17.So we can know that Magnaporthe oryzae from indica area have no significant differences is virulence to ZYQ8 or JX17.But, in 14 Magnaporthe oryzae from japonica area,9 Magnaporthe oryzae are susceptible to JX17. 14 Magnaporthe oryzae are resistant to ZYQ8.So we can know that strains from japonica area exhibit the specificity to JX17.3?we selected 51 Magnaporthe strains which can used to experiment tested the pathogenicity in the indica ZYQ8 and japonica JX17. The results showed that about 50%(27) Magnaporthe oryzae have significant differences in pathogenicity between ZYQ8 and JX17.But ZYQ8 is resistant to18 Magnaporthe oryzae,JX17 is resistant to 9 Magnaporthe oryzae.So the resistance to rice blast in ZYQ8 is better than that in JX17.4?Through combining indica and japonica DH population genetic map and the pathogenicity result, we can locate the disease resistance genes. there are four strains located at chromosome 11,include 168.724-195.992 c M ? 182.334-195.992 c M ?184.276-195.992 c M and 89.324-89.324 c M, three strains located at chromosome 12,include 53.469-62.209 c M ? 25.295-30.15 c M and 38.889-63.18 c M, two strains located at chromosome 9, include 111.23-151.532 c M?157.842-167.458 c M,one strain located at chromosome 1 225.35-232.148 c M.5?We can analysis the resistance gene locus within the targeting range and classify by Gene ontology.we can gain 1244 gene locus associated with the disease from 6763 gene locus in 10 targeting range,to narrow the range of the resistance gene.We discussed the pathogenic differences of Magnaporthe oryzae between ZYQ8 and JX17,the comparation between the resistance loci and the cloned gene, in order to offer the information of cloning the resistance gene. |
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