禾谷镰刀菌拮抗菌株的筛选及鉴定

Screening and Identification of Bacillus spp. Strains With Biocontrol Activity Against Fusarium graminearum

禾谷镰刀菌引起的小麦赤霉病能够导致小麦产量的大幅降低和品质的严重损失。为探索赤霉病生物防治方法,本试验从扬花期被禾谷镰刀菌侵染的麦穗上分离得到28株芽孢杆菌,利用平板对峙法对其进行筛选,其中20株菌对禾谷镰刀菌表现出明显的拮抗作用。根据生理生化特性和16S rDNA序列分析,这20株拮抗菌分别被鉴定为甲基营养型芽孢杆菌(11株)、解淀粉芽孢杆菌(2株)、枯草芽孢杆菌(2株)、暹罗芽孢杆菌(3株)和特基拉芽孢杆菌(2株)。这些菌株能够有效降低小麦赤霉病的发病率、发病程度和病情指数,其中菌株JS62N、JS15E和JS29I能够将赤霉病发病率降低80%以上;菌株JS29I、JS62N、JS39C和JS39D能够将赤霉病发病程度降低80%以上。16株菌能将病情指数降低80%以上;所有菌株均能极显著增加小麦的百粒重,JS12Q效果最好(+101.4%)。本研究结果为小麦赤霉病的防治提供了生物防治材料。

Fusarium head blight（ FHB）,caused by Fusarium graminearum,leads to great losses of wheat yield and quality. To explore the potential biocontrol against FHB,28 Bacillus spp. strains were screened from the infected wheat spikelets by antagonistic trials against F. graminearum. Among which,20 isolates significantly exhibited antifungal activity against F. graminearum. Based on the analyses of their physiological and biochemical characteristics,and 16 S rDNA sequence,these strains were separately identified as B. methylotrophicus（ 11 isolates）,B. amyloliquefaciens（ 2isolates）,B. subtilis（ 2 isolates）,B. siamensis（ 3 isolates） and B. tequilensis（ 2 isolates）. These isolates could effectively reduce the severity incidence and index of FHB. The disease incidence was obviously decreased by more than80% by three isolates,namely IS62 N,JS15E and JS29 I. JS29 I,JS14C,JS62 N,JS39C and JS39 D could decrease disease severity by over 80%. Moreover,16 isolates reduced the FHB index by more than 80%. All the isolates could significantly increase（ P ≤ 0. 01） hundred-grain weight,the best of which was B. methylotrophicus JS12Q（ ＋101. 4%）. The results suggest that these Bacillus strains could be potential biocontrol agents against FHB.