楸树茎腐病致病菌的分离鉴定及不同楸树材料抗病性差异

Isolation and Identification of the Pathogen of Catalpa bungei Stem Rot and Differences in Disease Resistance of Different Catalpa Species

为明确楸树茎腐病的致病原因,了解不同楸树材料对致病菌的抗性差异,采用组织分离法从感病楸树植株中分离纯化菌株并验证其致病性,之后进行形态与分子鉴定,采用离体叶片穿刺法和浸根法将致病菌接种至不同楸树材料,测定不同楸树材料叶片β-1,3-葡聚糖酶、超氧化物歧化酶(SOD)、过氧化物酶(POD)的活性变化。结果表明,楸树茎腐病的病原菌为露湿漆斑菌(Myrothecium roridum)。在离体叶片穿刺试验中,洛楸1号(CL1)病情指数最低,为39.17;在浸根法试验中,金丝楸(CJS)病情指数最低,为26.67。3个楸树材料中,CJS的β-1,3-葡聚糖酶活性变化最快,其活性峰值比CL1高14.89%,比豫楸2号与灰楸的杂交种(CZ2)高7.12%;CL1的SOD活性上升最快;CL1和CJS的POD活性分别在第3天和第6天达到峰值,且CJS的峰值比CL1高11.11%,比CZ2高25.00%。综合病情指数和酶活性变化,CJS对茎腐病的抗性更强。

In order to clarify the pathogenic cause of Catalpa bungei stem rot,and to understand the differences in resistance of different Catalpa species to the pathogen,fungi strains were isolated and purified from the diseased Catalpa tree plants by tissue separation method to verify their pathogenicity,and then morphological and molecular identification was carried out.The pathogen was inoculated into different Catalpa species by in vitro leaf puncture method and root dipping method,and activity changes ofβ-1,3-glucanase,superoxide dismutase and peroxidase were measured.The results showed that the pathogen of Catalpa bungei stem rot was Myrothecium roridum.In the in vitro leaf puncture test,the disease index of Catalpa bungei Luoqiu 1(CL1)was the lowest,which was 39.17.In the root dipping test,the disease index of Catalpa bungei var.Jinsi(CJS)was the lowest,which was 26.67.Among the three Catalpa species,theβ-1,3-glucanase activity of CJS changed the fastest,and its peak activity was14.89%higher than that of CL1 and 7.12%higher than a hybrid of Catalpa bungei Yuqiu 2 and Catalpa fargesii Bur.,which was called CZ2.The SOD activity of CL1 increased the fastest.The POD activities of CL1 and CJS reached their peaks on the 3rd and 6th days respectively,and the peak value of CJS was11.11%higher than that of CL1 and 25.00%higher than that of CZ2.By comprehensive consideration of disease index and enzyme activity changes,CJS was more resistant to stem rot.