解淀粉芽孢杆菌L-H15的促生与抗病特性研究

对解淀粉芽孢杆菌(Bacillus amyloliquefaciens)L-H15的促生抗病特性进行了研究,分析了全基因组序列中促生抗病相关基因,并在表型上对菌株形成生物被膜、根际定殖、固氮溶磷解钾、分泌铁载体和植物激素等能力进行测定。结果表明:L-H15具有形成生物被膜的能力,且在根系表面定殖的菌数超过10~5CFU/g,分泌铁载体的相对表达量为60.22%,分泌IAA、CTK和GA含量最多可达到61.35 pmol/L、48.93 ng/m L和82.46 pmol/L,对立枯丝核菌(Rhizoctonia solani)和尖孢镰刀菌(Fusarium oxysporum)的抑菌带直径分别为(8.67±1.15)mm和(2.50±0.50)mm。综上所述,解淀粉芽孢杆菌L-H15具有多重促生抗病能力,在未来实际应用方面具有良好的生防潜力。

Characteristics of Growth-promotion and Antibiosis by Bacillus amyloliquefaciens L-H15

Bacillus amyloliquefaciens is a kind of plant growth promoting rhizobacteria (PGPR). This kind of beneficialrhizosphere bacterium plays a key role in increasing soil fertility, promoting plant growth and suppressing the growth of phytopathogens in the field of agriculture. This characteristics of growth-promotion and antibiosis of Bacillus amyloliquefaciens L-H15 was studied. Genes which were relevant to the characterizations of growth-promotion and antibiosis of B. amyloliquefaciens L-H15 were analyzed based on the complete genome sequencing. Meanwhile, the capabilities of biofilm formation, nitrogen fixation, phosphate and potassium solubilization, production siderophores and phytohormones were measured. The results indicated that L-H15 showed the capability of biofilm formation and the amount of bacteria which could colonize the root surface was up to 105CFU/g. The relative expression of siderophores was 60.22%, and the production of IAA, CTK and GA could reach 61.35pmol/L, 48.93ng/mL and 82.46pmol/L, respectively. The diameters of inhibition zone were (8.67±1.15)mm and (2.50±0.50)mm, respectively, when cocultured L-H15 with two fugal pathogens, i.e., Rhizoctonia solani and Fusarium oxysporum. In conclusion, L-H15, which showed excellent characterizations in both aspects of growth-promotion and antibiosis, had great potential to become a biological control agent in the future.