肿节风炭疽病拮抗细菌的筛选与鉴定

为筛选出对肿节风炭疽病菌Colletotrichum dematium具有拮抗作用的细菌,开发新型生物制剂,本试验分别采用组织分离法和稀释平板法,从广西药用植物园科研基地健康肿节风植株的不同组织和根系土壤分离、纯化获得49株细菌。平板对峙试验结果表明,来自土壤的zjt-9、zjt-4,来自根系的zgs21及叶片的zyy13对肿节风炭疽病菌具有较强的拮抗作用,其中作用最强的是zjt-9。抗菌谱测定结果表明, zjt-9、zjt-4和zyy13对供试的18种病原真菌均有明显的拮抗效果,拮抗作用最强的是zjt-9,平均抑菌宽度最高达19.10 mm;经显微镜观察,拮抗细菌可造成肿节风炭疽病病原菌菌丝膨大、畸形、断裂。通过形态学特性和16S rDNA鉴定,zjt-9菌株为甲基营养型芽胞杆菌Bacillus methylotrophicus。

Screening and identification of the bacteria antagonistic to Colletotrichumdematium of Sarcandra glabra

In order to develop new biocontrol agents with stable antagonistic effect on Colletotrichum dematium of Sarcandra glabra, a total of 49 strains of bacteria were isolated from different tissues of healthy plants and soils in the Guangxi Medicinal Botanical Garden Research Base by dilution method and tissue isolation tests. The results of plate confrontation test showed that zjt-9, zjt-4, zgs21 and zyy13 had antagonistic effect on the anthracnose of S. glabra; one strain of bacterium with promising antagonistic activity was obtained, which was strain zjt-9. Strains of zjt-9 and zjt-4 were isolated from soil, strains of zgs21 and zyy13 were isolated from plant roots and seedling leaves; antibacterial spectrum tests showed that it had significantly antagonistic activities to 18 plant pathogens, and zjt-9 had the strongest antagonistic activity with an antagonism width of 19.10 mm. When observed under the microscope, the mycelia of C. dematium were swollen, abnormal and cracked. Based on morphological and 16S rDNA sequence analysis, strain zjt-9 was identified as Bacillus methylotrophicus.