具有生防功效的玉米秸秆降解复合菌系的构建

【目的】构建具有生防功效的玉米秸秆降解复合菌系，以提高玉米秸秆的降解率，并有效防治植物病害。【方法】通过对可产芽孢的11株纤维素降解菌（X₁～X₁₁）、17株半纤维素降解菌（B₁～B₁₇）、19株木质素降解菌（M₁～M₁₉）及1株生防菌（L）间亲和性的测定，构建复合菌系。测定复合菌系对玉米秸秆的降解能力，筛选出最优的复合菌系；通过16S rDNA序列分析，对组成最优复合菌系的菌株进行鉴定。以小麦种子发芽指数（GI）为指标，利用模拟堆肥试验研究最优复合菌系对玉米秸秆腐熟进程的影响；通过田间试验，研究最优复合菌系对番茄生长、产量的影响，并探讨其对番茄灰霉病的防治效果。【结果】通过亲和性试验初步构建了Z1(LM₅X₄B₂)、Z2(LM₃X₇B₅)、Z3(LM₃X₁₀B₂)和Z4(LM₅X₁₀B₁₂)4个复合菌系，其中复合菌系Z1综合效果最好，其对玉米秸秆的降解率最高（45.9%）。喷施复合菌系Z1的发酵液可加快玉米秸秆腐熟进度，堆肥第25天时GI值超过85%，玉米秸秆完全腐熟，腐熟进程较喷施清水的对照提前了4 d。秸秆还田时喷施Z1发酵液，可促进番茄生长，提高番茄产量，并且对番茄灰霉病具有一定的防治效果（防治效果为27.92%）。经16S rDNA测序，鉴定组成复合菌系的L为类芽孢杆菌、X₄为枯草芽孢杆菌、M₅和B₂为解淀粉芽孢杆菌。【结论】构建的复合菌系Z1具有生防和降解秸秆的双重功效，且使用成本低、操作简单，具有潜在的应用价值。

Construction of composite microbial system with capacity of straw degradation and biocontrol efficacy

【Objective】 The system of biocontrol strains of corn straw degradation compound was built to improve the utilization of corn straw degradation and effective control of plant diseases.【Method】 In order to construct composite microbial asystem with capacity of straw degradation and biocontrol efficacy,we constructed asystem by antagonistic tests among 11 cellulose-degrading strains(X1-X11),17 hemicellulose-degrading strains(B1-B17),19 lignin-degrading strains(M1-M19) and an antifungal strain(L),and they are all spore-forming.The use of affinity determination,ability to antagonize the activity and degradation of straw comprehensive determination of the compound selected the best strains for composting,and field trials for strains that make up the optimal composite strains were determined by 16S rDNA sequence analysis.Take wheat germination index(GI) as the index,the simulated test studied the optimal composting compound strains of corn straw rotten process.Through field experiment,the optimal compound strains,influence on tomatoes growth and production was studied to investigate the control effect of tomato grey mould.【Result】 Through the initial compatibility test four complex strains of Z1(LM5X4B2),Z2(LM3X7B5),Z3(LM3X10B2) and Z4(LM5X10B12) were built,then the best one with high antifungal activity was chosen and straw degradation was chosen for further research.Results showed that the Z1 had the best comprehensive effect;spraying fermentation of Z1 can speed up the progress of straw decomposition,its GI value was higher than 85% after 25 days,after complete maturity,it was 4 days earlier than CK;spraying fermentation of Z1 in straw returning can promote tomato growth,increase yield,and prevent tomato gray mold to some degrees,the inhibitory rate was 27.92%.Z1 passed the sequencing of 16S rDNA,the strain of L was identified to be Paenibacillus sp.The strain of X4 was identified to be Bacillus subtilis.The strain of M5 was identified to be Bacillus amyloliauefaciens.The strain of B2 was identified to be Bacillus amyloliauefaciens.【Conclusion】 The results showed that the composite microbial system which we constructed has bifunctional of biocontrol and degrading of straw,costs low,and applies easily,which has good potential applications.