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对安徽省淮北市番茄植株根、茎、叶中内生放线菌进行了分离、筛选,并测定了其抑菌活性。结果表明:番茄根、茎和叶中的内生放线菌的数量分别为5.66×104、0.67×104和0.39×104CFU.g-1鲜重。根据分离部位和表型特征,从健康番茄植株体内分离到93株内生放线菌,通过对峙实验,筛选到7株对番茄灰霉病菌有拮抗作用的菌株,占所分离内生放线菌总数的7.5%。来自根组织中的菌株HNU-EA27的抑菌效果最佳,抑菌圈直径达28.3mm。根据形态特征、培养特征、生理生化特性、细胞壁组分和16SrDNA序列分析,将菌株HNU-EA27鉴定为毒三素链霉菌(Streptomyces toxytricini)。室内测定菌株HNU-EA27发酵滤液对灰霉病菌菌丝生长及分生孢子萌发的抑制作用,结果表明:菌株HNU-EA27发酵滤液可以抑制灰霉病菌菌丝生长和分生孢子萌发,且浓度越高,抑制能力越强;当发酵滤液浓度为30%时则完全抑制灰霉病菌菌丝生长和分生孢子萌发。盆栽防效试验结果表明:30%菌株HNU-EA27发酵滤液对番茄灰霉病的预防与治疗效果分别为80.6%和73.8%,均高于50%多菌灵可湿性粉剂600倍液。本研究表明,菌株HNU-EA27是防治番茄灰霉病潜在的优良生防菌株,具有良好的开发应用价值。
Endophytic actinomycetes in roots, stems and leaves of tomato plants in Huaibei City of Anhui Province were isolated and screened, and their antibacterial activities were determined. The results showed that the number of endophytic actinomycetes in roots, stems and leaves of tomato were 5.66 × 104, 0.67 × 104 and 0.39 × 104CFU.g-1 fresh weight, respectively. Ninety-three strains of endophytic actinomycetes were isolated from healthy tomato plants according to their isolates and phenotypic characteristics. Seven strains that antagonized Botrytis cinerea were screened through confrontation experiments, 7.5% of the total. The bacterium HNU-EA27 from the root tissue showed the best bacteriostatic effect, and the diameter of the bacteriostatic circle reached 28.3mm. The strain HNU-EA27 was identified as Streptomyces toxytricini based on morphological characteristics, culture characteristics, physiological and biochemical characteristics, cell wall components and 16S rDNA sequence analysis. The results showed that the fermentation filtrate of HNU-EA27 inhibited the mycelium growth and conidiospore germination of Botrytis cinerea, and the higher the concentration High, inhibitory ability is stronger; when the fermentation filtrate concentration is 30%, the mycelium growth and conidia germination of Botrytis cinerea are completely inhibited. The results of pot experiment showed that the preventive and therapeutic effects of 30% strain HNU-EA27 fermentation broth on tomato gray mold were 80.6% and 73.8%, respectively, higher than that of 50% carbendazim WP 600 times. This study showed that the strain HNU-EA27 is a potential excellent biocontrol strain against Botrytis cinerea, which has good development and application value.