小菜蛾肠道成团泛菌PxG45的分离鉴定及其抗真菌活性  

Isolation and identification of Pantoea agglomerans PxG45 from Plutella xylostella(Lepidoptera:Plutellidae)gut and its antifungal activities

作　　者：付东冉 许小霞[1] 冯淑杰[2] 金丰良[1] FU Dong-Ran;XU Xiao-Xia;FENG Shu-Jie;JIN Feng-Liang(National Key Laboratory of Green Pesticides,College of Plant Protection,South China Agricultural University,Guangzhou 510642,China;Laboratory of Plant Protection,College of Horticulture,South China Agricultural University,Guangzhou 510642,China)

机构地区：[1]华南农业大学植物保护学院,绿色农药国家重点实验室,广州510642 [2]华南农业大学园艺学院植物保护实验室,广州510642

出　　处：《昆虫学报》2023年第10期1343-1353,共11页Acta Entomologica Sinica

基　　金：国家自然科学基金项目(32172498,31972345)。

摘　　要：【目的】昆虫肠道共生细菌是栖息在昆虫肠道中的微生物,是肠道微生物群落中最主要的成员。它们对昆虫的生长发育、营养吸收以及免疫系统均具有重要影响。本研究通过对小菜蛾Plutella xylostella肠道共生细菌进行分离培养和功能鉴定,以探究肠道共生细菌对小菜蛾适应性的影响及其对真菌的广谱抑制作用。【方法】利用体外平板培养分离纯化小菜蛾3龄幼虫肠道细菌PxG45菌株,结合形态学、16S rDNA基因测序和生理生化测定进行菌种鉴定。利用生物测定探究PxG45对小菜蛾3龄幼虫存活率及球孢白僵菌Beauveria bassiana侵染小菜蛾3龄幼虫对存活率的影响。通过平板对峙法检测PxG45对球孢白僵菌的抑制作用,进一步检测PxG45对植物病原真菌希金斯炭疽菌Colletotrichum higginsianum、刺盘孢炭疽菌C.camelliae、尖孢镰刀菌古巴专化型4号生理小种Fusarium oxysporum f.sp.cubense race 4、茄链格孢菌Alternaria solani、稻瘟病菌Magnaporthe oryzae和丁香假单胞菌杨梅致病变种Pseudomonas syringae pv.myricae的广谱抗性。【结果】小菜蛾3龄幼虫肠道菌PxG45为成团泛菌Pantoea agglomerans。与未饲喂PxG45的对照组相比,饲喂PxG45不仅显著提高了健康小菜蛾3龄幼虫的存活率,还提高了球孢白僵菌侵染后3龄幼虫的存活率。与PxG45拮抗培养的球孢白僵菌和6种植物病原真菌的菌落直径均显著小于单独培养球孢白僵菌和6种植物病原真菌时的直径,与PxG45拮抗培养后真菌的生长均被抑制。【结论】成团泛菌PxG45通过直接的抑菌作用影响小菜蛾对外界的适应性,且这种抑菌作用具备广谱性,可显著抑制植物病原真菌的生长。本研究表明PxG45具备生防菌潜力,并为利用害虫肠道共生菌提供新思路。【Aim】Gut symbiotic bacteria in insects,the main members of the gut microbial community,play important roles in the growth and development,nutrient absorption,and immune system of insects.In this study,a gut symbiotic bacterium of Plutella xylostella was isolated and cultured,and its function was identified to explore the influence of the gut symbiotic bacteria on the adaptability of P.xylostella and the broad-spectrum inhibitory activities against fungi.【Methods】The gut bacterium,PxG45,was isolated and purified from the 3rd instar larva of P.xylostella by plate culture in vitro.Morphological characterization,16S rDNA gene sequencing,and physiological and biochemical characterization were used to identify the bacterial species.The effects of PxG45 on the survival rate of the 3rd instar larva of P.xylostella and the effects of the Beauveria bassiana infection on the survival rate of the 3rd instar larva of P.xylostella were detected by bioassay.The inhibition of PxG45 on B.bassiana was defined by plate confrontation method to further detect the broad-spectrum resistance of PxG45 to the plant pathogenic fungi Colletotrichum higginsianum,C.camelliae,Fusarium oxysporum f.sp.cubense race 4,Alternaria solani,Magnaporthe oryzae and Pseudomonas syringae pv.myricae.【Results】PxG45 in the gut of the 3rd instar larva of P.xylostella was identified as Pantoea agglomerans.Compared with the control group which was not fed with PxG45,supplemental PxG45 not only significantly increased the survival rate of the healthy 3rd instar larva of P.xylostella,but also improved the survival rate of the 3rd instar larva infected by B.bassiana.The colonial diameters of B.bassiana and six plant pathogenic fungi in antagonistic culture with PxG45 were significantly smaller than those cultured alone of B.bassiana and six plant pathogenic fungi,and the growth of fungi was inhibited after antagonistic culture with PxG45.【Conclusion】PxG45 affects the adaptability of P.xylostella by direct and broad-spectrum antibacterial effects,and

关 键 词：小菜蛾 成团泛菌PxG45 提高存活率 抗真菌活性 

分 类 号：Q965.8[生物学—昆虫学]