小麦-条锈菌互作过程中活性氧及保护酶系的变化研究

 对条锈菌与小麦不同互作体系中组织学特征、活性氧产生及其相关酶系的变化进行了研究。组织学观察表明:非亲和组合相对于亲和组合存在明显差异,表现为菌丝生长受抑,吸器母细胞和吸器形成减少,寄主细胞在接种后18h左右出现过敏性坏死。生化测定结果表明:在非亲和组合中,O₂^-的产生速率和H₂O₂的含量均高于亲和组合,且O₂^-产生速率在接种后12h达到一个峰值,H₂O₂的含量在接种后20和72h出现2个高峰。而在亲和组合中,O₂^-产生速率低于对照或与对照相似,H₂O₂的含量虽然高于对照,但却普遍低于非亲和组合;SOD在亲和组合中的活性总体上要高于非亲和组合;接种24h后,CAT在2种组合中的活性均高于对照,在接种后36和48h时,亲和组合中的CAT活性高于非亲和组合,而在接种60h后又开始低于非亲和组合;POD活性在接种24h后均明显升高,但亲和组合中POD活性增幅大;MDA在非亲和组合中于接种后72h含量明显上升。结果表明,亲和与非亲和组合中条锈菌扩展、活性氧的产生及相关酶活变化都存在明显差异,这些差异与小麦抗锈性的表达可能有密切联系。

Changes of reactive oxygen species and protective enzymes in the interaction of wheat and Puccinia striiformis f.sp.tritici

Histological characteristics of pathogen development, production of reactive oxygen species (ROS) and activities of relative enzymes were analyzed in the incompatible and compatible interactions between wheat and Puccinia striiformis f. sp. tritici. Histological observation revealed that there were distinct differences between the incompatible interaction and compatible interaction, which included inhibition of hyphal growth, formation decrease of haustorial mother cells and haustoria, and hypersensitive cell death in host tissues occured at 18 h after inoculation (hai) in incompatible ones. The results of biochemical measuration showed the rate of O₂^- production and content of H₂O₂ were higher in the incompatible interaction than that in the compatible interaction, and the peaks of O₂^- appeared at 12 hai, H₂O₂ content reached its maxima at 20 hai and 72 hai. However, in the compatible interaction, the rate of O₂^- production were lower or similar to control, and H₂O₂ content were higher than that in control but lower than in incompatible ones. The SOD activities in compatible interaction were usually higher than that in incompatible ones. At 24 hai, the CAT activities in both interactions were all higher than that in control, and CAT activities in compatible interaction were higher than that in incompatible ones at 36 hai and 48 hai, but after 60 hai, CAT activities in compatible interaction were lower than that in compatible ones again. The POD activities increased obviously in both interactions at 24 hai, but more rapidly in compatible ones. The MDA contents were increased significantly at 72 hai in incompatible interaction. The results indicated that there were striking differences about pathogen development, ROS production and relative enzymes activities in the incompatible and compatible interactions, which might have close relationship with resistance expression of wheat against stripe rust fungus.