莲子草假隔链格孢SF 193固体发酵培养基的筛选及其对空心莲子草的控制效果

【背景】空心莲子草是一种源于南美洲且正在我国不断传播的外来入侵植物。莲子草假隔链格孢是空心莲子草的强致病菌,能引起空心莲子草茎叶发病,抑制空心莲子草生长。【方法】选择以麦麸、大米、玉米芯粉、玉米粉、稻秸秆粉为基料,棉籽壳、稻秕壳和大豆粉为辅料,按照一定质量比配制固体培养基,筛选适合莲子草假隔链格孢SF-193大量生产的有效组分;同时研究培养基含水量和6种金属离子对SF-193菌落生长的影响。【结果】在以大米和大豆粉质量比为3:1和5:1的培养基上SF-193菌落面积最大,其次为大米和棉籽壳质量比为5:1的培养基。在含水量为20%和30%的培养基上SF-193菌落面积显著大于其他培养基。Mg2+和Mn2+对SF-193菌落生长影响较小,Zn2+对SF-193菌落生长具有显著的抑制作用,而SF-193菌落在含Cu2+和Fe3+的培养基上不能生长。田间控草试验表明,固体发酵生产的菌粉对空心莲子草的致病性显著高于液体菌,用量为50g.m-2时,10d后空心莲子草的病情指数达86.1。【结论与意义】利用固体培养基发酵生产的莲子草假隔链格孢对空心莲子草的防除效果显著优于液体发酵。因此,莲子草假隔链格孢SF-193固体发酵菌粉可能在生物防治空心莲子草方面具有重要作用。

Solid-state fermentation of Nimbya alternantherae isolate SF-193 and control of Alternanthera philoxeroides

Background]Alternanthera philoxeroides is an invasive plant which originated from South America and is currently spreading in China.Nimbya alternantherae isolate SF-193 is a phytopathogenic fungus which could cause foliar and stem necrosis of A.philoxeroides and inhibit the growth of the weed in the field.Method]Agricultural by-products,such as bran,rice,powder of corn cob,cornmeal,rice stover,cotton seed hull,rice husk,and soybean powder were selected as basic or auxiliary material to develop a solid-state medium for growing the pathogen isolate SF-193.Further,the effect of water and metal ion content in the solid-state medium on the growth of the fungus was investigated.Result]The area of colony was the largest when the isolate SF-193 was cultured on media composed of rice and soybean powder with ratios of 3:1 and 5:1,respectively,follwed by the mix of rice and cotton seed hull with ratio 5:1.The colony areas of the isolate SF-193 cultured in the media containing 20% and 30% water were significant larger than those of media with different water content.Compared with control,the area of colony measured on the media with Mg2+ and Mn2+ had no significantly difference.Colony growth was inhibited on media containing Zn2+,while no colony was observed on media containing Cu2+ and Fe3+.Under field conditions,disease severity causd by the fungal powder was significantly higher than that obtained by liquid fermentation and reached 86.1 at dosage of 50 g·m-2.Conclusion and significance]The efficiency controlling of A.philoxeroides by using the fungal powder fermented was remarkably higher than that of the fungus fermented with liquid media.These results suggested that isolate SF-193 powder fermented by solid-state fermentation could potentially play a role in biocontrol of A.philoxeroides.