贝莱斯芽孢杆菌YB-145对小麦纹枯病的防治效果及促生作用

Biological Control of Sharp Eyespot and Growth Promotion in Wheat by Bacillus velezensis YB‑145

为探寻对小麦具有促生作用并高效防治小麦纹枯病的优良菌株,首先采用平板对峙法测定菌株YB-145对禾谷丝核菌、西瓜枯萎病菌、小麦根腐病菌、芹菜早疫病菌、花生果腐病菌、禾谷镰刀菌6种植物病原菌菌丝生长的抑制作用,然后根据其形态特征、生理生化特征和16S rRNA基因测序对该菌株进行鉴定;之后分别采用皿内水培法、盆栽法和田间试验测定菌株YB-145对小麦纹枯病的生物防治效果及对小麦的促生作用。结果表明,菌株YB-145为贝莱斯芽孢杆菌(Bacillus velezensis),能够抑制上述6种病原菌菌丝的生长,其中对禾谷丝核菌菌丝生长的抑制作用最明显。该菌株还能够产生IAA(吲哚乙酸)和铁离子载体,具有分泌蛋白酶和β-1,3-葡聚糖酶活性。1×10^(7)、1×10^(8) cfu/mL YB-145菌悬液浸种能显著提高小麦根鲜质量、地上部鲜质量和地上部高度,并且1×10^(8) cfu/mL YB-145菌悬液浸种对小麦幼苗纹枯病的防效达到73.31%。田间试验结果显示,YB-145菌液拌种处理对小麦纹枯病的田间防治效果高达63.37%,使小麦增产8.2%,与化学农药6%戊唑醇悬浮种衣剂拌种处理(药剂对照)的防治效果(73.65%)和增产率(5.8%)没有明显差异。因此,贝莱斯芽孢杆菌YB-145是一株具有生防潜力的菌株,可用于小麦纹枯病的防控。

The aim was to find an excellent strain with growth‑promoting effect on wheat and efficient control of wheat sharp eyespot.Firstly,the inhibitory effect of strain YB‑145 on mycelial growth of six plant pathogens,including Rhizoctonia cerealis,Fusarium oxysporum f.sp.niveum,Bipolaris sorokinana,Alternaria solani,Fusarium moniliforme and Fusarium graminearum PH‑1 was studied in dual cultures on PDA plates.Furthermore,the strain was identified according to its morphological,physiological and biochemical characteristics and 16S rRNA gene sequencing.The growth‑promoting effect of strain YB‑145 on wheat and its biological control effect on sharp eyespot were determined by Petri dish,pot and field experiments.The results showed that strain YB‑145 was identified as Bacillus velezensis,which could produce IAA(indole acetic acid)and siderophores and had extracellular protease andβ‑1,3‑glucanase activities.In dual cultures,Bacillus velezensis YB‑145 significantly inhibited mycelial growth of 6 plant pathogens,especially R.cerealis.Bacillus velezensis YB‑145 at doses of 1×10^(7) cfu/mL and 1×10^(8) cfu/mL significantly promoted growth of wheat seedlings with more fresh weight of roots,fresh weight of shoots and height of shoots.Moreover,the efficacy of Bacillus velezensis YB‑145 at a doses of 1×10^(8) cfu/mL in controlling wheat sharp eyespot reached 73.31%.Field investigation showed that the control effect of strain YB‑145 on sharp eyespot was up to 63.37%and the yield of wheat increased by 8.2%.The control effect(73.65%)and yield‑increasing rate of wheat(5.8%)of the treatment with 6%tebuconazole suspension had no significant difference with YB‑145.The above results demonstrate that Bacillus velezensis YB‑145 is a promising biological control agent to both promote wheat growth and suppress wheat sharp eyespot.