干旱对解淀粉芽孢杆菌(Bacillus amyloliquefaciens)FZB42生物被膜的形成及根际定殖能力的影响

Effects of Drought Stress on the Biofilm Formation and Root Colonization Ability of Bacillus amyloliquefaciens FZB42

解淀粉芽孢杆菌(Bacillus amyloliquefaciens)FZB42是一种植物根际促生菌(PGPR),能够促进植物生长,提高植物抵抗病害\,干旱和盐胁迫的能力。但关于干旱胁迫下解淀粉芽孢杆菌FZB42自身生物被膜形成能力及根际定殖能力的研究鲜见报道。利用PEG-6000模拟干旱胁迫,进行渗透势分别为-0.05、-0.50、-1.48、-2.95 MPa的干旱胁迫处理,测定分析此胁迫条件对解淀粉芽孢杆菌FZB42的生长、生物被膜的形成、根际定殖能力以及胞外多糖产量的影响,为进一步阐明解淀粉芽孢杆菌FZB42对提高植物的抗干旱能力提供理论依据。结果表明:(1)高浓度的PEG-6000能够显著抑制解淀粉芽孢杆菌FZB42的生长、生物被膜的形成及在拟南芥(Arabidopsis thaliana)根际的定殖能力。当添加15%PEG-6000时,生物被膜吸光度(OD600)和根际定殖数量达到最低值,分别为1.542和1 500 cfu·mm^-1。(2)解淀粉芽孢杆菌FZB42的胞外多糖分泌量随PEG-6000浓度的增加而增加。不添加PEG-6000时,胞外多糖含量最低为150.2 mg·L^-1。当添加15%PEG-6000时,胞外多糖的产量最高为568.8 mg·L^-1。

Bacillus amyloliqueliciens FZB42 is a plant growth-promoting rhizobacteria(PGPR) that promotes plant growth, improves disease resistance, drought and salt tolerance abilities. However, there are few reports on the growth, biofilm formation, root colonization ability and exoposaccharides production of B. amyloliquefaciens FZB42 under drought stress. In this study, PEG-6000 was used to simulate drought stress, and the osmotic potentials were-0.05,-0.50,-1.48 and-2.95 MPa, respectively. The growth, biofilm formation, rhizosphere colonization ability and extracellular polysaccharide yield of B. amyloliquefaciens FZB42 under different concentrations of PEG-6000 were determined. This paper provided a theoretical basis for improving the drought resistance of plants by B. amyloliquefaciens FZB42. The results showed that:(1) High concentration of PEG-6000 can significantly inhibit the growth, biofilm formation and colonization ability of B. amyloliquefaciens FZB42 in Arabidopsis rhizosphere. When 15% PEG-6000 was added, the OD600 and numbers in the rhizosphere reached the lowest values of 1.542 and 1 500 cfu·mm-1, respectively.(2) The production of exoposaccharides of B. amyloliquefaciens FZB42 increased significantly with the increasement of PEG-6000 concentration. When there was none PEG-6000, the extracellular polysaccharide content was the lowest at 150.2 mg·L-1. When 15% PEG-6000 was added, the yield of extracellular polysaccharide was the highest at 568.8 mg·L-1.