地黄根圈土壤拮抗放线菌筛选_鉴定及发酵条件优化[1]

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1、地黄根圈土壤拮抗放线菌筛选_鉴定及发酵条件优化[1]地黄根圈土壤拮抗放线菌筛选、鉴定及发酵条件优化林雁冰..陆家贤..颜..霞..刘博野..方..松..范元青(西北农林科技大学生命科学学院,陕西杨凌712100)摘要:为研究中药地黄根圈土壤拮抗性放线菌在植物病害生物防治中的应用潜力,用常规方法从地黄根圈土壤中分离获得42株放线菌。采用琼脂块法进行初筛,用纸片扩散法和生长速率法对抑菌效果最好的菌株DHR11进行抑菌活性复筛,通过形态、培养特征及16SrDNA序列分析研究其分类地位,并采用正交设计对从6种培养基中筛选的最佳培养基进行优化。结果表明:4株放线菌对供试植物病原真菌有较好的拮抗作用,其中

2、菌株DHR11对苹果炭疽病菌Colletotrichumgloeospori..oides的抑菌活性最高,抑菌圈直径达30mm,抑菌率达52.5%;菌株DHR11发酵9天时抑菌活性最高;最优培养基组成为:蔗糖15g、可溶性淀粉25g、大豆粉10g、酵母膏7.5g、K2HPO40.5g、自来水1000mL;最佳发酵条件为:培养基初始pH7.5,接种量15%(v/v),摇床转数220r/min,装瓶量80mL/250mL,28..发酵9天。根据形态、培养特征及16SrDNA序列分析,初步鉴定DHR11为加利利链霉菌Streptomycesgalilaeus。关键词:拮抗放线菌;筛选;发酵优化;抑菌

3、活性;地黄Screening,identificationandoptimizedfermentationconditionofantagonisticactinomycetesfromRehminnaeglutinosorhizosphereLinYanbing..LuJiaxian..YanXia..LiuBoye..FangSong..FanYuanqing(CollegeofLifeSciences,NorthwestA&FUniversity,Yangling712100,ShaanxiProvince,China)Abstract:Inordertoconfirmthepotent

4、ialapplianceofanantagonisticactinomycetesforbiocontrolofplantdiseases,42strainsofactinomyceteswereisolatedfromrhizospheresoilofRehminnaeglutinosothroughconventionalmethods.Agarblockmethodwasusedaspreliminaryscreening,anddiskdiffusionmethodandgrowthspeedratemethodwereusedassecondaryscreeningoftheinhi

5、bitioneffectofstrainDHR11.ThetaxonomicidentificationofstrainDHR11wasstudiedthroughitsmorphologica,lculturalcharacteristicsand16SrDNAsequencealignmen.tThebestliquidfermentationmediumscreeningoutsixmediawasoptimizedbyorthogonalarrayexperiments.Resultsshowedthat4strainsofactinomycetesex..hibitedbetteri

6、nhibitionactivitytoplantpathogenicfungitestedthanotherstrains.Amongthese4strains,strainDHR11exhibitedthestronges.tThebiggestinhibitionzonewasupto30mmindiameter,withaninhibitionratewas52.5%onColletotrichumgloeosporioides.StrainDHR11hadthestrongestan..tibacterialactivityafterbeingfermentedfor9days.Liq

7、uidfermentationmediumforstrainDHR11wasscreenedoutthroughoptimizationexperimen,twithingredientsofsucrose15g,solublestarch25g,soy..beanmeal10g,yeastextract7.5g,K2HPO40.5g,tapwater1000mL,theoptmialfermen