番茄灰霉病拮抗内生放线菌的筛选、鉴定及其活性评价

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。

Screening, identification, and activity assessment of endophytic actinomycetes from tomato plants against Botrytis cinerea

In this study,the endophytic actinomycetes in tomato plants in the farmlands in Huaibei City of Anhui Province were isolated and screened,and the bio-activities of the actinomycetes against pathogenic fungus Botrytis cinerea were determined.The population density of the actinomycete in the tomato roots,stems,and leaves were 5.66×104,0.67×104,and 0.39×104 CFU·g-1 fresh weight,respectively.According to the isolation position and phenotype characteristics,a total of 93 endophytic actinomycete strains were isolated from different tissues of healthy tomato plants,and,by using dual culture technique,7 strains with antagonistic activities against B.cinerea were screened,accounting for about 7.5% of the endophytic actinomycetes isolated.Among the 7 strains,the HNU-EA27 isolated from tomato roots had the best inhibition effect,with a formed inhibition zone of 28.3 mm.Based on the morphology,cultural characteristics,physiological and biochemical properties,chemotaxonomy,and 16S rDNA sequencing,the HNU-EA27 was identified as Streptomyces toxytricini.The culture filtrate of HNU-EA27 could inhibit the mycelium growth and spore germination of B.cinerea.The higher concentration the culture filtrate,the stronger the inhibition activity was.30% culture filtrate of the HNU-EA27 could completely inhibit the mycelium growth and spore germination of B.cinerea.Pot experiment showed that the prevention efficiency and cure efficiency of 30% HNU-EA27 culture filtrate against tomato gray mould were 80.6% and 73.8%,respectively,being superior to those of the 600-fold dilution of 50% badistan.It was suggested that the strain HNU-EA27 could be valuable in the bio-control of tomato gray mould.