一株拮抗立枯丝核菌的放线菌筛选、鉴定及生理特性

Screening,identification and physiological characteristics of an actinomycete strain against Rhizoctonia solani

通过对峙实验,从采集自黄渤海海域的双齿围沙蚕(Perinereis aibuhitensis)中分离到一株内生放线菌SCF-18,并对其抑菌活性进行分析。SCF-18对立枯丝核菌(Rhizoctonia solani)和小麦根腐病菌(Bipolaris sorokiniana)都具有拮抗作用,且对立枯丝核菌生长的拮抗效果最为明显,生长抑制率为89.78%。抑菌试验结果表明:菌株SCF-18发酵滤液可以抑制立枯丝核菌丝的生长,发酵液浓度越高,抑制力越强;当发酵液浓度达到50%时,对两种病原菌的抑制率分别为89.78%和80.26%。菌株SCF-18生长特性试验结果表明:菌株SCF-18生长最适温度为30℃,最适pH值为7;放线菌SCF-18耐盐度可达5%。根据形态特征、培养特征、生理生化特性和16S rDNA序列分析,将放线菌SCF-18初步鉴定为淡紫灰链霉菌(Streptomyces lavendulae)。本研究发现,SCF-18菌株是防治立枯丝核菌等病原菌的潜在优良生防菌株,具有潜在的开发应用价值。

By using dual culture technique, a strain of endophytic actinomycete named SCF-18 was screened out and isolated from Perinereis aibuhitensis collected from the Huanghai and Bohai Sea, and the bio-activities of the actinomyeete against pathogenic fungi were determined. The strain SCF-18 showed significantly antagonistic activities to both Rhizoctonia solani and Bipolaris sorokiniana, particularly more potent to R. solani with the maximum inhibition rate of 89.78%. The fermentation filtrate of SCF-18 could inhibit the growth of R. solani in a dose-depended man- ner. Furthermore, the fermentation filtrate of SCF-18 in 50% concentration showed the maximum growth inhibitory effects to R. solani and H. sativurn with inhibition rates of 89. 78% and 80.26%, respectively. The optimum growth condition for SCF-18 was at 30 ℃ with pH 7. The highest tolerance of salinity of SCF-18 was 5%. Based on the analysis of morphology, cultural characteristics, physiological and biochemical properties, and 16S rDNA sequencing, the SCF-I 8 was identified as Streptomyces lavendula. Our results suggest that the strain SCF-18 could be val- uable in the bio-control of R. solani.