防治平贝母菌核病的木霉菌筛选及室内防效

Screening of Trichoderma spp. to control Sclerotinia sclerotiorum-induced sclerotiniose in Fritilla ussuriensis Maxim. and the laboratory control effect

摘要:

【背景】由病原菌Sclerotium denigrans侵染引起的平贝母菌核病是其主要的鳞茎病害之一，给平贝母种植产业带来了巨大的损失。【目的】筛选出对平贝母菌核病具有拮抗效果的木霉菌株。【方法】以平贝母菌核病作为靶标菌，采用平板对峙试验、平板对扣法、圆盘滤膜法与发酵液抑菌试验筛选对平贝母菌核病具有拮抗效果的木霉菌株。采用顶空固相微萃取的方法检测拮抗效果较好的木霉菌挥发性成分；二硝基水杨酸(dinitrosalicylic acid, DNS)比色法测定木霉菌的β-1,3葡聚糖酶的活性；室内防效试验验证其对平贝母菌核病的防治效果。【结果】平板对峙试验发现木霉菌F1、F2和D6对平贝母菌核病菌的生长具有较强的抑制作用，其抑菌率分别为91.06%、87.00%和86.12%；平板对扣法发现木霉菌E17和A26对菌核病菌的抑制效果最为明显，抑菌率分别为74.96%和75.86%；圆盘滤膜法发现菌核病菌在F2、C6、D3、F4、A26、B30、D4和D6的琼脂培养基上均不生长，抑菌率达100%；发酵液抑菌试验表明木霉菌D3抑制效果最强，可完全抑制菌核病菌的生长，抑菌率为100%；对A26、D4、E8、E17和D3这5株木霉进行GC/MS挥发性产物分析，在E17发现了具有抗真菌活性的6-戊基-2H-吡喃-2-酮等活性物质；DNS比色法发现β-1,3葡聚糖酶活性最高的木霉菌为F1；室内防效试验测定发现D3能明显抑制平贝母鳞茎菌核病的病变，对平贝母菌核病具有潜在的生防活性。【结论】木霉菌D3在防治平贝母菌核病中是极具开发价值的菌种。

关键词:平贝母;菌核病;木霉菌;生物防治;挥发性产物

Abstract:

[Background] Sclerotinia sclerotiorum-induced sclerotiniose in Fritilla ussuriensis is one of the main bulb diseases, which causes huge loss to the industry of F. ussuriensis. [Objective] To screen Trichoderma strains against S. sclerotiorum. [Methods] Eligible strains were identified based on plate confrontation assay, two-sealed-base-plates method, disc filter membrane method, and the test of the inhibitory effect of fermentation broth. Headspace solid-phase microextraction was used to detect the composition of volatile components of Trichoderma strains with better antagonistic effect. The β-1,3 glucanase activity of strains was assayed with the DNS method. Experiment on in vitro bulbs was carried out to verify the effect on S. denigrans. [Results] Strains F1, F2, and D6 had strong inhibitory effect on the growth of S. denigrans and the inhibition rates were 91.06%, 87.00%, and 86.12%, respectively. According to the disc filter membrane test, S. denigrans did not grow on the agar with F2, C6, D3, F4, A26, B30, D4, and D6 and the inhibition rate was up to 100%. The two-sealed-base-plates test indicated that E12 and A26 had the most obvious inhibitory effect, with the inhibition rates of 74.96% and 75.86%, separately. The test on the fermentation broth showed that D3 had the strongest inhibitory effect, which could completely inhibit the growth of S. denigrans (inhibition rate: 100%). The volatile products of A26, D4, E8, E17, and D3 were analyzed by GC/MC, and the antifungal active substances of E17 such as 6-n-pentyl-2H-pyran-2-one were found. F1 was found to have the highest β-1,3 glucanase activity. According to the laboratory test, D3 can significantly inhibit the pathological changes of sclerotiniose in bulbs of F. ussuriensis and has potential biocontrol activity. [Conclusion] Trichoderma D3 has great potential for the control of S. denigrans.

Key words:Fritillaria ussuriensis Maxim.;Sclerotium denigrans;Trichoderma;biological control;volatile products