芒果炭疽病拮抗菌 L18-7菌株的筛选、 鉴定及拮抗机制研究.

【Objective】The present paper aimed to screen antagonistic bacterial strains of mango anthracnose, so as to lay a theoretical basis for biological control of mango anthracnose and provide strain resources.【Method】Colletotrichum asianum,the dominant species of mango anthrax, was used as the target, and 37 strains of Bacillus spp. obtained in previous studies were used for confrontation culture and in vitro inoculation test. The antagonistic strains with obvious control effect were selected and their antagonistic mechanism was analyzed.【Result】The results of confrontation test showed that the inhibitory rates of 10 antagonists against C. asianum were more than 78.00%,among which the inhibitory rates of M12-5,L18-7,L19-3,L17-3 and M11-6 reached 96.24%,94.94%,94.10%,91.25% and 90.00%,respectively. Eight strains of Bacillus spp. with obvious control effect were obtained by in vitro inoculation, among which strains L18-7 and L16-4 had the best control effect, with the average control efficiency of 83.00% and 79.16%,respectively. There was no significant difference between them(P＞0.05). Combined with morphological characteristics, 16S rDNA sequence and phylogenetic tree analysis based on rpoB gene sequence, strain L18-7 could be identified as B. velezensis. Strain L18-7 could produce extracellular protease and cellulase, and could produce active antagonists in five media including Luria-bertani(LB),beef peptone(NA) and potato glucose agar(PDA) etc. Strain L18-7 carried genes related to antibiotic production such as mycB,ituA,yndJ,fenB and bacA.【Conclusion】The antagonistic bacterium strain L18-7 of mango anthracnose was identified as B. velezensis. The strain grew well on LB medium at 28 ℃.It could produce antagonistic substances, extracellular protease and cellulase and carried related genes of antibiotics such as mycB,ituA,yndJ,fenB and bacA. It can be used as germplasm resources for biocontrol bacteria. [ABSTRACT FROM AUTHOR]