杨树根腐病生防菌的筛选及鉴定

【目的】杨树作为我国最重要的工业用材林树种之一,对其长期的生产力维护和人工林的健康管理是林业和生态建设的重中之重。近年来,杨树根腐病的防治措施作为林学界亟待解决的重要问题,目前以化学防治方法为主,但其存在许多环境危害,所以具有诸多优点的生物防治成为了现在国内外的研究焦点,找到生防菌是研究的重中之重。以一系列实验分离筛选到用于防治根腐病的低温适生菌为创新点,旨在找到对杨树根腐病菌具有拮抗作用的生防菌,并明确其分类地位,令其在杨树根腐病的生物防治生防菌种类方面作为参考,也为进一步研究其定殖特性、林间防效及生物安全性等问题提供前期基础。【方法】为了筛选出新的低温适生生防菌菌种资源,采用稀释涂布平板法从杨树土壤中分离得到20株芽孢杆菌,经过初步筛选得到了拮抗效果最好的一株芽孢杆菌B42,并对其进行分离纯化,采用平板对峙法对该芽孢杆菌的抑菌活性进行测定,然后鉴定明确其分类地位。【结果】该芽孢杆菌对杨树根腐病菌具有显著的拮抗作用,同时对茄病镰刀菌、红松根腐病镰刀菌、山核桃干腐病菌、链格孢、油茶炭疽病菌、白腐菌均具有广谱抗性。【结论】根据菌体的形态特征、生理生化指标以及16S rDNA序列分析的结果,鉴定该菌B42为贝莱斯芽孢杆菌Bacillus velezensis。

Screening and identification of bacteria used for biological control of poplar root rot

【Objective】As one of the most important industrial timber forest species in China-Poplar, its long-term productivity maintenance and health management of plantation forests are the top priority of forestry and ecological construction. In recent years, the prevention and control measures of poplar root rot have been the important problem to be solved in the forestry academic community. At present, chemical control is a popular way of control, but it causes many environmental problems. Therefore the biological control with many advantages has attracted a lot of attention, and it becomes the focus of research. Then finding biocontrol bacteria is the top priority of the research. In this study, a series of experiments are used to isolate and screen low temperature suitable bacteria for root rot, aiming to find biocontrol bacteria with antagonistic effect on poplar root rot, and to clarify its taxonomic status and make it a reference for the biological control of poplar root rot, it also provides a preliminary basis for further research on its colonization characteristics, forest control and biosafety.【Method】In order to screen out the new low-temperature suitable biocontrol bacteria resources, 20 bacillus strains were isolated from the poplar soil by using the method of dilution coated tablet in this study, and one strain B42 with best antagonistic effect is obtained by screening at the first stage. After the isolation and purification, the antibacterial spectrum of pathogenic bacteria were determined by using tablet confrontation. Finally B42 is identified and its classification status was clarified.【Result】The results show that B42 had significant antagonistic effect on poplar root rot, and it also hasbroad-spectrum resistance to Fusarium solani, Fusarium oxysporum, Botrytis cinerea, Alternaria, Camellia anthracis and White rot fungus.【Conclusion】According to the morphological characteristics, physiological-biochemical indexes and 16S rDNA sequence analysis, the strain B42 is identified as Bacillus velezensis.