黄绿绿僵菌Ma130821菌株的分子鉴定及产孢特性研究

Identification and Conidial Production Characteristics of the Metarhizium sp. Strain Ma130821

【目的】鉴定从云南省玉溪市峨山县塔甸镇玉米田自然罹病蛴螬分离培养获得的绿僵菌Ma130821种类,明确该菌株在害虫生防制剂开发应用的潜力。【方法】根据微生物菌落培养特征和产孢结构特征,结合ITS-5.8S DNA序列,对绿僵菌Ma130821进行种类鉴定,同时对其产孢特性进行研究。【结果】绿僵菌Ma130821为黄绿绿僵菌(Metarhizium flavoviride),该菌株Ma130821在大米、麦麸、玉米粒和稻壳基质上固相培养后均能生长和产孢,但产孢量不同。其中在大米基质上,黄绿绿僵菌的每克孢子含孢量和每克基质产孢数均为最高,同时所产孢子萌发率极显著高于其他培养基所产孢子(P<0.01),由此以大米为基质,系统研究了黄绿绿僵菌Ma130821菌株的产孢特性。发现在25℃条件下,黄绿绿僵菌在大米基质上每克孢子含孢量最高达到1.47×109个,极显著高于28℃和30℃(P<0.01),所产孢子在48 h时的萌发率达到100%;16 L∶8D光照条件下每克孢子粉产孢量高达5.07×108个,极显著高于14 L∶10 D光照条件下的产孢量,在第48小时时,16 L∶8 D条件下所产孢子的萌发率达到100%。【结论】从云南省玉溪市峨山县塔甸镇玉米田自然罹病蛴螬分离培养获得绿僵菌Ma130821为黄绿绿僵菌(M. flavoviride)。以大米为固相产孢基质,在25℃、16 L∶8D的培养条件下最适宜该菌株分生孢子扩大培养。

[Purpose]The biological characteristics of Metarhizium Ma130821 was isolated from the infected grub in corn field in E’shan County of Yuxi City,Yunnan Province.To make sure the species and to clarify the potentiality for the biocontrol based on Metarhizium Ma130821.[Method]The strain Ma130821 was identified based on the characteristics of morphological,cultural characteristics of microorganism colony and ITS-5.8S gene sequence,the conidial production characteristics was studied in the laboratory at the same time.[Results]The strain Ma130821 was identified as Metarhizium flavoviride.The strain Ma130821 could be cultured on rice,corn grain,wheat bran and rice husk,but the sporulation was different on the different medium.The conidia sporulation on the rice media was higher than on other solid mediums under the same culture conditions(P<0.01).The germination rate of spores was also higher than on other three solid media and the germination rate was nearly 100%for 48 h.The optimal temperature for production of spores was at 25℃,the sporulation was maximum,significantly higher than that of under the 28 and 30℃(P<0.01),it was 1.47×109 spores/g.The germination rate of spores was 100%after the culture for 48 h.The optimum photoperiod for spores production was at the 16 L:8 D photoperiod with a sporulation of was 5.07×108 spores/g,which was significantly higher than that under the14 L:10 D photoperiod.[Conclusion]Based on the above results,the rice medium was suitable for expanding culture of Ma130821,the optimal condition was 25℃and photoperiod of 16 L:8 D.