大丽轮枝菌拮抗芽孢菌株的分离、鉴定及两株菌抑菌特性研究

从新疆和硕连作棉田根际土壤中分离到146株芽孢细菌.29株对大丽轮枝菌(Verticillium dahliae Kleb)具有拮抗作用的菌株中有9株拮抗性极强.经鉴定,9株拮抗性极强的菌株中有2株属短小芽孢杆菌(Bacillus pumilus),7株与枯草芽孢杆菌(B.subtilis)相近.抑菌特性实验表明:J-02和J-15的抑菌高峰分别出现在衰亡期和稳定期,对pH的耐受范围分别为5~9和7~9;J-02的热稳定性较好,J-15对温度较敏感,但100℃处理后仍有抑菌活性;J-02能够抑制大丽轮枝菌芽管伸长形成菌丝,J-15可导致大丽轮枝菌菌丝畸形,失去产孢能力.盆栽实验表明,J-02和J-15这2株拮抗菌对棉花黄萎病有明显防治作用.综合结果表明J-02和J-15均有作为棉花黄萎病生防菌的潜能.

Isolation and identification of antagonistic Bacillus spp.against Verticillium dahliae :the antibacterial properties of two strains

Cotton Verticillium wilt is the most serious fungal disease in Chinese cotton production,screening for its control for stable and high yields is of great significance in China.We have isolated antagonistic Bacillus strains against Verticillium dahliae from healthy continuously-cropping cotton rhizosphere soil in Xinjiang.A total of 146 strains were obtained and 29 strains showed varied degrees of antagonism to Verticillium dahliae.Of these strains J-02 and J-29 belonged to Bacillus pumilus and the remainder are similar to B.subtilis.We found that the strongest inhibition of J-02 on Verticillium dahliae was in decline phase,J-15 in stable phase and inhibition was stable in the pH range from 5～9 for J-02 and 7～9 for J-15 respectively.Strain J-02 was found to be more resistant to heat,J-15 was sensitive to temperature,but there was still an inhibition zone after 100 ℃ treatment J-02 inhibited the germ tube of Verticillium dahilae elongates to form mycelium.J-15 caused mycelium of Verticillium dahliae to be deformed,and to fail to produce spores.In pot experiments,J 02 and J-15 showed a certain protective effect on cotton Verticillium wilt.In conclusion,strains J-02 and J-15 have potentials as biocontrol vectors against cotton Verticillium wilt.