枯草芽胞杆菌Qh-618对燕麦叶斑病防治效果研究

Control Effect of Bacillus subtilis Qh-618 on Oat Leaf Spot

燕麦叶斑病是燕麦Avena sativa生产中重要的病害之一,由燕麦德氏霉菌Drechslera avenae(Eidam)Shoemaker引起,主要危害叶片和叶鞘,多发于燕麦的灌浆期,严重影响燕麦的正常生产。为有效控制该病害,本研究通过平板对峙及水解酶活性测定试验,从燕麦生境中分离获得一株生防菌株Qh-618,对多种病原真菌都具有较强的抑菌活性,抑菌率达60%以上,对德氏霉菌D.avenae的孢子萌发也具有显著的抑制效果;水解酶活性检测发现,Qh-618具有较强的蛋白酶、多聚半乳糖醛酸酶、嗜铁素酶及吲哚乙酸产生活性;经生理生化测定、16S rDNA及gyrB基因测序鉴定其为枯草芽胞杆菌Bacillus subtilus。进一步温室试验结果表明,生防菌Qh-618在对燕麦叶斑病的防治效果达65%以上;与此同时,Qh-618对燕麦的生长也具有较强的促进作用,与对照组相比,生防菌Qh-618处理组燕麦的叶绿素含量、根长、苗长、根重、苗重等生物量增加方面都显著高于对照组植株。田间试验结果显示,枯草芽胞杆菌Qh-618对燕麦叶斑病的防治效果达58.57%,此外,燕麦的叶绿素含量、株高、生物量等均有显著的提高,燕麦产量也显著提升,增产11.2%。综上所述,枯草芽胞杆菌Qh-618是一株对燕麦叶斑病具有较高防治潜力的生防促生菌株。

Oats leaf spot,caused by Drechslera avenae(Eidam)Shoemaker,is one of the most important diseases of oats(Avena sativa).It commonly happens in the filling stage,penetrates from leaves and leaf sheaths,and finally leads to great loss of oats yield.To control the disease effectively,a biocontrol strain Qh-618 was isolated from oat habitat by antagonistic analysis and hydrolase activity test.Qh-618 showed strong antagonistic activity against many pathogenic fungi,with the inhibition rate of more than 60%on mycelium growth and significant inhibition on spore germination D.avenae.In addition,Qh-618 was proved to have apparent protease,galactosidase,ferritase and indoleacetic acid production activities.Through physiological and biochemical analysis and 16S rDNA and gyrB gene sequence analysis,Qh-618 was identified as Bacillus subtilis.Greenhouse experiment showed that Qh-618 could controlthe oats leaf spot efficiently,with the efficiency of more than 65%,and meanwhile,promote the growth of oats.The chlorophyll content,root length,seedling length,root weight,seedling weight and other biomass of oats were all up-regulated with the treatment of Qh-618.Field experiment showed that Qh-618 could control oat leaf spot by 58.57%,and increased the chlorophyll content,plant height and biomass of oats significantly,which led to the increase of the yield by 11.2%.In conclusion,B.subtilis Qh-618 is a biocontrol agent with growth-promotion activity and high potential for controlling oat leaf spot.