枯草芽孢杆菌CAB-1抑菌蛋白对黄瓜白粉病的防治作用

采用子叶喷雾法分别测定了枯草芽孢杆菌Bacillus subtilis CAB-1所产抑菌蛋白粗提物对黄瓜白粉病的保护和治疗生物活性。结果表明该抑菌蛋白粗提物能显著降低黄瓜白粉病的病情指数,其保护和治疗作用的效果分别为73.33%和76.85%;EC50分别为175μg.mL-1和125μg.mL-1。利用曲利苯兰染色法检测抑菌蛋白粗提物对黄瓜白粉菌Sphacrotheca fuliginea生长的影响,结果表明该抑菌蛋白粗提物能有效降低白粉菌分生孢子的萌发率及萌发的芽管个数,造成菌丝顶端畸形膨大呈球状并减少新生分生孢子的个数。接菌3 d后,对照的孢子萌发率为36.98%,而经抑菌蛋白粗提物处理后的孢子萌发率仅为4.8%;接菌7 d后对照每个分生孢子梗上串生孢子个数最多为7个,多数5～6个;而抑菌蛋白粗提物处理后每个分生孢子梗上串生孢子个数最多为2个,大部分为1个。

Inhibitive Effect of Antifungal Protein Produced by Bacillus subtilis CAB-I against Sphaerothecafuliginea in Cucumber

Effect of crude protein produced by Bacillus subtilis CAB-1 on cucumber powdery mildew （CPM） caused by Sphaerothecafuliginea was tested by using cotyledon-spraying method. Results showed that the crude protein reduced the disease index of CPM significantly. The protective and curative effects were 73.33% and 76.85%, respectively; and the EC50 values were 175 μg·mL-1 and 125μg·mL-1, respectively. The inhibitory activity of the crude protein against S. fuliginea on cucumber cotyledons was detected by using trypan blue staining method. Microscopic observations revealed that the crude protein inhibited the mycelial growth and conidial production, and made the germinating conidia and mycelia bulbous and swollen. The germination rate of the treated conidia was only 4.8% in contrast to 36.98% of untreated conidia at 3 days after inoculation onto cucumber leaves. Only 1 conidium formed averagely, in contrast to 5--6 conidia formed, on each conidiophore in cucumber leaves at 7 days after inoculation with treated and untreated conidia, respectively.