论文部分内容阅读
为有效评价生防菌对香蕉尖孢镰刀菌古巴转化型(Fusarium oxysporum f.sp.cubense,FOC4)B2的防病能力,通过对收集的生防菌资源进行抗性筛选,对249个测试菌中筛选到的3株拮抗菌A5-6、D7-16和CL7进行了抑菌观察、抗病谱测定、土壤抑菌能力监测及盆栽苗拮抗能力测定,并对测试菌进行了形态观察和16S r DNA测序鉴定。显微观察显示:3个拮抗菌会导致病原菌B2的菌丝发育畸形、膨胀、胞壁增厚、部分形成泡状、内容物外渗生长以及抑制孢子的萌发。抑菌谱测试表明,菌株对包括FOC4以内的其他真菌性病害抑菌率在60%以上,但对尖孢镰刀菌其他专化型抑菌率较低,仅在40%~50%之间。土壤拮抗性能评价结果表明:拮抗菌单独处理对土壤中FOC数量的控制有限,只能降低1个数量级,但对处理盆栽苗中土壤FOC数量的控制能下降到2个数量级。盆栽实验表明,菌株A5-6以72.3%的防病效果较D7-16(45.4%)、CL7(50.0%)的防效之间差异达到了极显著。3个菌株经形态学和16S r DNA序列鉴定表明D7-16为短短芽胞杆菌(Brevibacillus brevis),A5-6和CL7也属于芽胞杆菌,3个菌株都是香蕉镰刀菌枯萎病潜在的良好生防资源,可作为生防菌做进一步的开发性研究。
In order to effectively evaluate the anti-pathogenicity of biocontrol agents against Fusarium oxysporum f.sp.cubense (FOC4) B2, we screened 249 tested bacteria The antibacterials A5-6, D7-16 and CL7 were screened for antibacterial activity, antibacterial spectrum, antibacterial activity of soil and antagonistic ability of potted seedlings. The morphological observation and 16S r DNA sequencing identification. Microscopic observation showed that the three antagonistic bacteria could lead to mycelial malformation, swelling, thickening of cell wall, bubble formation in part, extravasation of contents and inhibition of spore germination. The antibacterial spectrum test showed that the bacteriostasis rate of the strains to other fungal diseases including FOC4 was more than 60%, but the inhibitory rate to other Fusarium oxysporum strains was lower at only 40% -50%. The results of soil antagonistic performance evaluation showed that the antagonistic bacteria alone had limited control on the amount of FOC in soil, which could only be reduced by one order of magnitude, but the control of soil FOC amount in potted seedlings could be reduced to two orders of magnitude. The pot experiment showed that the control effect of strain A5-6 at 72.3% was more significant than that of D7-16 (45.4%) and CL7 (50.0%). The three strains were identified by morphological and 16S r DNA sequence. The results showed that D7-16 was Brevibacillus brevis, A5-6 and CL7 also belonged to Bacillus, and all three strains were potentially good fusarium wilt disease Anti-resources, as biocontrol bacteria for further development of research.