泽漆内生菌的分离筛选及其对烟粉虱的毒杀作用

Isolation and screening of endophytes from sun spurge Euphorbia helioscopia and their insecticidal effects against tobacco whitefly Bemisia tabaci

中文关键词:烟粉虱  泽漆  内生菌  几丁质酶  杀虫活性

keywords:Bemisia tabaci  Euphorbia helioscopia  endophytic bacteria  chitinase  insecticidal activity

中文摘要:为发掘泽漆Euphorbia helioscopia内生菌资源并筛选用于生物防治烟粉虱Bemisia tabaci的高效菌株，以泽漆茎和叶片为材料，采用组织块分离法与组织匀浆法分离内生菌，采用透明圈法初筛具有产蛋白酶和几丁质酶能力的菌株，利用3,5-二硝基水杨酸法测定初筛菌株的几丁质酶活性，并采用饲喂法测定目标菌株发酵液上清液及其粗酶液对烟粉虱的毒杀作用，结合形态学观察与分子生物学鉴定方法对目标菌株进行鉴定。结果表明：从泽漆茎、叶片中共分离45株菌株，其中4株菌株同时具有产蛋白酶和几丁质酶的能力。在这4株菌株中，菌株J3在蛋白酶检测平板中出现透明圈，同时在几丁质酶检测平板上也生成透明圈，透明圈边缘清晰，透亮均一，清晰度高。随发酵时间延长菌株J3中几丁质酶活性呈规律性动态变化，有较大的产酶潜力。菌株J3发酵液上清液和粗酶液对烟粉虱均有毒杀作用，处理48 h时烟粉虱成虫的死亡率分别达78.00%和96.67%。结合形态学观察和分子生物学鉴定方法将菌株J3鉴定为链霉菌属Streptomyces sp.。表明从泽漆茎、叶中分离纯化获得的菌株J3可作为生物防治烟粉虱的潜在菌种资源。

Abstract:To explore endophytic microbial resources from sun spurge Euphorbia helioscopia and obtain high-efficiency strains for the biological control of tobacco whitefly Bemisia tabaci, endophytes were isolated from the stems and leaves of E. helioscopia using tissue segment separation and tissue homogenization techniques. Strains with the ability to produce protease and chitinase were preliminarily screened using the clear zone method. The chitinase activity of the primarily screened strains was determined by the 3, 5-dinitrosalicylic acid method. The toxic effect of the fermentation supernatant and crude enzyme solution of the target strain against B. tabaci was evaluated using the feeding method. The target strain was identified with morphological observation and molecular biological methods. The results showed that a total of 45 strains were isolated from the stems and leaves of E. helioscopia, and four strains capable of producing both protease and chitinase were obtained from the primary screening. Among these four strains, strain J3 produced clear zones on both protease and chitinase detection plates, with the zones exhibiting clear edges, transparency, uniformity, and high definition. The chitinase activity of strain J3 showed a regular dynamic change over fermentation time, indicating a high enzymeproducing potential. Both the fermentation supernatant and crude enzyme solution of strain J3 exhibited insecticidal activity agains B. tabaci, with the mortalities of adult whiteflies reaching 78.00% and 96.67%, respectively, after 48 h of treatment. Strain J3 was identified as Streptomyces sp. based on morphological observation and molecular biological identification. These results indicate that strain J3 isolated and purified from the stems and leaves of E. helioscopia can serve as a potential microbial resource for the biological control of B. tabaci.