枯草芽孢杆菌N1729对棉花主要病原菌的抑菌作用及其蛋白特性的初步研究

Preliminary Research on Inhibition Effect of Bacillus subtilis N1729 on the Main Pathogenic Fungi of Cotton and Its Protein Characters

N1729是从棉花根际土壤分离出的拮抗细菌,通过形态、生理生化特征以及16 SrDNA的分子序列同源性分析,鉴定N1729是枯草芽孢杆菌(Bacillus subtilis)。采用平板对峙法测定结果表明该菌对棉花立枯病菌、枯萎病菌和黄萎病菌均具有较强的抑菌作用,其中对立枯病菌的抑菌带最宽,为18.3 mm(3 d后),抑制率为45.7%。该菌无细胞滤液,对以上三种病原菌具有一定的抑菌作用,其中对立枯病菌的抑菌作用最好,抑制率为33.8%。还利用N1729不同稀释浓度无细胞滤液培养棉花无菌胚,发现无细胞滤液对幼苗具有一定的促生作用,稀释10倍无细胞滤液的促生作用最大,胚轴长度20.2 mm,较对照增加23.2%。通过硫酸铵沉淀法提取N1729粗提蛋白,发现该菌粗提蛋白耐高温、对氯仿不敏感、对胰蛋白酶敏感。

N1729, a strain of antagonistic bacteria, was isolated from cotton rhizosphere. The results indicated this Strain showed strong antagonism against Rhizoctonia solani , Fusarium oxysporum f. sp. vasinfectum and Venicillium dahliae. N1729 was identified as Bacillus subtilis based on the results of morphologic characteristics, physiological and biochemical properties and phylogenetic analysis of 16SrRNA sequence. N1729 showed strong antagonism against cotton RAizoctonia solani, Fusarium oxysporum f. sp. vasinfectum, and Verticillium dahliae by plates inhibition methods. And some characters of exudates filtrate of antagonistic strain with different dilution times were made in modified PDA plates. It was found that the extract filtrate enhanced the growth of seeding hypocotyl length, the length of the hypocotyl treated by extract fihrate is 20.2mm, compared with hypocotyl length of control. The results showed their crude substance endured acid, and alkali, especially endured heat（ 121℃）, and the crude substance of the strain was sensitive to Tryroteinase treatment.