链霉菌Ahn75菌剂助剂的筛选及对水稻稻瘟病的防效研究

Screening of Adjuvants for Streptomyces griseobrunneus Ahn75 Agent and Its Control Effects on Rice Blast

为了研制一种高效防治水稻稻瘟病菌剂,本文以水稻稻瘟病病原菌高效拮抗内生菌株灰褐色链霉菌Ahn75为研究对象,分析了不同助剂,包括营养物质、润湿剂、分散剂、紫外保护剂和稳定剂等对孢子萌发和菌剂稳定性能的影响,并探讨了优良助剂协同生防菌株对水稻稻瘟病的防效。结果发现,叶面肥、酵母提取物、吐温80和糊精均能显著促进链霉菌Ahn75孢子的萌发,且糊精还可一定程度保护Ahn75孢子免受紫外线伤害,而稳定剂海藻酸钠对链霉菌Ahn75孢子萌发影响最小,且表现出比其他稳定剂更好的稳定性能。室外盆栽试验显示,各助剂与Ahn75孢子悬浮液复配均能显著降低水稻叶瘟的发病率和病情指数,其中混合助剂的协同防效最佳,叶瘟防效达38.06%。结合室内和室外试验结果,最终确定菌剂的最佳配方为:孢子含量1×10^(8) CFU/mL、营养物质酵母提取物的质量分数0.05%、润湿分散剂吐温800.05%、紫外保护剂糊精1.00%、稳定剂海藻酸钠0.15%。该研究为生防链霉菌Ahn75菌株的田间应用提供了重要的理论依据和支撑。

In order to develop a biocontrol agent with high eficiency for rice,an endophytic Streptomyces griseobrunneus Ahn75 with high antagonistic activity aganist rice blast pathogen was used as material,and the effects of different adjuvants,including nutrient,wetting dispersant,stabilizer and UV protective on the germination of Ahn75 spores and the stability of Ahn75 agent were analyzed,then the biocontrol efficencies of excellent adjuvants synergistic with biocontrol strain on rice blast was assessed.The results showed that foliar fertilizer,yeast extract,Tween 80 and dextrin could significantly promote the germination of Streptomyces Ahn75 spores,and dextrin can also protect Ahn75 spores from UV damage at a certain extent,while sodium alginate as a stabilizer showed a less effect on the germination of spores and better stability than other stabilizers.The outdoor pet experiments showed Ahn75 spore suspension combined with each adjuvant can significantly reduce the incidence and disease index of rice leaf blast.Among them,the mixed adjuvants showed best synergistic control effect with a efficacy of 38.06%.Based on the results of indoor and outdoor tests,the best formulation of Ahn75 agent was finally determined as:spore concentration 1×10^(8) CFU/mL,yeast extract(0.05%)as nutrient,Tween 80(0.05%)as wetting dispersant,dextrin(1.00%)as UV protective,and sodium alginate(0.15%)as stabilizer.This study provides an important basis and support for the field application of biocontrol Streptomyces Ahn75.