解淀粉芽孢杆菌L-H15的促生与抗病特性研究

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

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。

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 growthpromotion 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 10～5 CFU/g. The relative expression of siderophores was 60. 22%,and the production of IAA,CTK and GA could reach 61. 35 pmol/L,48. 93 ng/m L and 82. 46 pmol/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.