稻瘟病菌与水稻CO39近等基因系互作的寄生适合度属性研究

Study on the attributes of parasitic fitness between CO39 near-isogenic rice lines and Magnaporthe grisea

选用以CO39为遗传背景的水稻CO39抗稻瘟病近等基因系(NILs)与广东省稻瘟病菌4个优势生理小种(ZC13、ZB1、ZB13和ZB5)构成16个亲和性和非亲和性互作组合,对各互作的4个寄生适合度属性(病斑平均扩展速率、感病型病斑比例、侵染成功率和病斑单位面积平均产孢量)进行了方差分析、多重比较和相关分析。方差分析表明,水稻NILs各品种、稻瘟病菌各小种以及品种×小种互作间的差异极显著。经多重比较,品种CO39和C104PKT之间在接菌相同小种时差异极显著,而品种C101LAC和C101A51之间虽差异不显著,但与前两品种间的差异极显著;小种ZC13和ZB1之间除单位病斑面积产孢量外另3个属性上差异不显著,但都显著高于ZB5和ZB13,而且ZB5也显著高于ZB13。相关分析表明,4个属性中每2个属性间均呈显著正相关,说明病菌小种在这个遗传背景相同的近等基因系中,可能具有相似的生存方式,病菌一旦克服寄主某方面的抗性后,所有生存适应性都一起提高,这是由于寄主的遗传同质性引起的。

The near-isogenic lines （NILs） of rice with CO39 genetic background and four major physiological races （ZC13, ZB1, ZB13 and ZB5） of rice blast fungus, Magnaporthe grisea, occurring in Guangdong Province, were used to measure four attributes of the parasitic fitness （average rate of lesion spread, proportion of susceptible lesions type, successful infection probability and average sporulation per lesion per square millimeter） on sixteen race x line combinations showing compatible and incompatible reactions. The variance analysis, multiple comparative and correlated analysis were applied to the four attributes. The results of variance analysis indicated that it is significantly different between cultivars, races and cultivat x race imeractions. By multiple comparative analysis, CO39 and C104PKT were significantly different from C101LAC and C101A51 when the same race was inoculated, though the later two cultivars were not significantly different from each other. Race ZC13 and ZB1 were not significantly different from each other, though they were significantly different from ZB5 and ZB13. ZB5 was significantly different from ZB13, except the infection probability. The correlated analysis showed significantly positive correlation between each of the two attributes. It suggested that the four races in NILs, with the same genetic background, had a resembled survival mode. Therefore, if the races overcome the resistance of the hosts in some way, their survival fitness would be raised altogether, which may be due to the hereditary homogeneity of the NILs.