H2O2参与大麦对白粉菌的防卫反应

抗病品种Ｓｕｌｔａｎ－５及其突变体与白粉菌小种Ａ６互作的细胞学研究表明，接种３６ｈ后，抗感品种中白粉菌分生孢子形成附着胞的频率及侵入频率无显著差异。抗病品种比感病品种过敏性反应细胞明显增多，过生反应与Ｍｌａ－１２基因型的大麦品种对白粉菌的小种专化抗性有关，用ＤＡＢ（地氨基联苯胺）观察到Ｈ２Ｏ２在乳突和过敏性反应细胞中积累。接各ｈ后在初生芽管的乳突以及接种１５ｈ后在附着胞下面的乳突有晕圈处有Ｈ２Ｏ２

H 2O 2 INVOLVED IN DEFENSE RESPONSE OF BARLEY TO POWDERY MILDEW INFECTION

Cytological study was performed in the interaction between powdery mildew isolate A6 and Mla12resistant wild type Sultan5 and mutant genotypes at 36 h after inoculation. The appressorium frequency and infection frequency were not apparently different in Sultan5 and mutant genotypes. The infection frequency in Sultan5, M100, M88, M66 and M22 was 8.3%, 7.4%, 8.5% and 8.7%, respectively. The result from the wholecell autofluorescence assay indicated that the frequency of hypersensitive reaction cell drastically increased in Sultan5 compared with susceptible mutant genotypes and that hypersensitive reaction was correlated with the Mla12 specified racespecific resistance to powdery mildew in barley. H 2O 2 accumulation in papillae and hypersensitive reaction cell was observed by DAB assay. H 2O 2 was detected in the epidermal cell wall subjacent to the primary tube from 6 h after inoculation and subjacent to appressorium from 15 h. The earliest time point for observation of H 2O 2 in hypersensitive reaction cell is 18 h after inoculation. The result that H 2O 2containing hypersensitive reaction cell frequency in Sultan5 was rapidly increased from 24 to 48 h after inoculation relative to susceptible mutant genotypes was consistent with the result of wholecell autofluorescence. H 2O 2 can induce hypersensitive reaction and possibly involved in hypersensitive reaction resistance of barley to powdery mildew fungus.