生防菌株W1防治植食性叶螨的物质基础及其功能研究

Phytophagous mites are worldwide pests. It has been shown that phytophagous mites have characters as follows: host broad, fast development, strong fertility, high resistance to pesticides, and it is difficult to control. In recent years, the harm of mites in our country is becoming more and more serious, so that the agricultural production has suffered great losses. In order to prevent mite’s damage effectively, it is necessary to carry out microbial control and its mechanism explanation. Bacillus amyloliquefaciens W1, isolated from the death mites naturally, is a great biocontrol strain against the agriculture mites, which had been used as bio-acaricide for the mites form corn, strawberry and apple at high lethal rate. Moreover, it has been proved that W1 could effectively colonize into the tissue of corn, tomato and broad bean such as root meristematic zone, elongation zone, stem, parenchyma and leaf. Now, to interpret the mechanism of the W1 acaricidal activities, the acaricidal compounds will be isolated from the supernatant of W1 and the chemical structure will be identified by using technologies of nature product research and structure chemistry coupled with the method of activity tracking. Then the toxicity and mechanism of compounds against the nymph, adult mites and eggs will be investigated and evaluated. The results of this research will be of profound significance to biocontrol of phytophagous mites.

植食性叶螨是一种世界性农林害螨，研究证明，其寄主广、发育快、繁殖力强，对化学农药极易产生抗药性，防治极为困难。近年植食性叶螨在我国危害日趋严重，使农林生产遭受巨大损失。为有效防止螨害，开展微生物防治及其机理解释是一项必要的基础性工作。解淀粉芽孢杆菌W1是从自然死亡的叶螨虫体上分离到的一株生防菌，其发酵液能有效防治玉米、草莓和苹果等植物上的害螨。前期工作证明W1能有效定殖于玉米、番茄和蚕豆等作物的根分生区、伸长区、茎髓部、薄壁及叶等组织中；W1发酵液的乙酸乙酯萃取物和正丁醇萃取物对叶螨具有很强的致死作用。据此本研究综合利用天然产物和结构化学分析技术，结合活性跟踪法，获取W1发酵液中杀螨活性化合物，鉴定其化学结构；明确化合物对成螨、若螨及其卵的毒力；阐明化合物对叶螨的生防功能及其作用方式。为植食性叶螨的微生物防治开辟新途径，为W1杀螨制剂开发提供科学依据，为杀螨生物农药研发奠定理论和物质基础。

叶螨是一种世界性农林害螨，其寄主广、发育快、抗药性强，防治极为困难。叶螨在我国危害日趋严重，使农林生产遭受巨大损失。解淀粉芽孢杆菌W1是从自然死亡的叶螨虫体上分离到的一株生防菌，其发酵液能有效防治玉米、草莓和番茄等植物上的害螨。通过活性跟踪从其发酵液中分离鉴定了10个化合物，包括8个环二肽：环（甘氨酸-苯丙氨酸）二肽、环（4-羟脯氨酸-苯丙氨酸）二肽、环（甘氨酸-络氨酸）二肽、环（脯氨酸-丙氨酸）二肽、环（脯氨酸-4-羟基脯氨酸）二肽、环（甘氨酸-脯氨酸）二肽、环（脯氨酸-脯氨酸）二肽、环（4-羟基脯氨酸-络氨酸）二肽；1个大环内酯；1个巨杆菌素。８个环二肽均表现出较好的杀螨活性，其LC50值为13.85~98.24 µM，其中环（4-羟基脯氨酸-络氨酸）二肽杀螨活性最强。研究首次证明了解淀粉芽孢杆菌W1的主要活性成分为2,5-二酮哌嗪（又称为环二肽）；首次发现2,5-二酮哌嗪具有叶螨触杀活性；发明了一种微剂量针式浸渍法测试杀螨活性；构建了一套系统评价杀螨活性的方法。研究结果为叶螨防治开拓了新思路，发现了新物质，为进一步深入开发研究指出了方向，奠定了物质基础。