拮抗内生细菌Bacillus mojavensisZA1在马铃薯根内及根际的定殖动态及其对土壤微生物的影响

利用GFP标记和平板分离法研究了拮抗内生细菌Bacillus mojavensisZA1在马铃薯根内及根际的定殖动态及其对土著微生物的影响。结果表明,标记菌株ZA1-gfp在土壤中定殖数量为3.7×10⁴~7.3×10⁴cfu/g;马铃薯根际为3.0×10³~1.5×10⁵cfu/g,根内为49~630cfu/g;马铃薯的根部横切面、根毛和根表皮等部位均观察到发绿色荧光的菌株ZA1-gfp菌体或聚集菌落。利用灌根法施入生防菌后,土壤中细菌、放射菌数量显著增加(P<0.05),土壤真菌数量在中期下降;土壤中细菌、真菌和放线菌的数量分别在相对稳定范围内(数据之间差异不显著)消长。该结果说明菌株ZA1-gfp能够在马铃薯根内及根际定殖且不影响土壤中土著微生物的群落稳定性。

Colonization of Antagonistic Endophytic Bacteria Bacillus mojavensis ZA1 in the Root of Potato and Rhizosphere Soil and Its Effect on Soil Microorganism

GFP labelling technique and plate culture method were used to study the colonization of endophytic bacterium Bacillus mojavensis ZA1 in the root of potato and rhizosphere soil and its effect on soil microorganism. The results showed that ZA1-gfp colonized well in soil with a density of 3.7×10⁴ to 7.3×10⁴ cfu/g and colonized in the roots of potato and rhizosphere with densities of 49 to 630 cfu/g and 3.0×10³ to 1.5×10⁵ cfu/g, respectively. ZA1-gfp could be detected in inner roots and on the root hairs and root epidermis of potato under a fluorescence microscope. The number of soil bacteria and actinomycetes were increased significantly (P<0.05) after ZA1-gfp inoculation using root-drenching method, but fungi was decreased in 25 days later after ZA1-gfp inoculation; the number of soil bacteria, fungi and actinomycetes was kept well (There was no obvious difference). The results showed that ZA1-gfp could steadily colonize the roots of potato and rhizosphere and the community stability of soil microorganisms was kept well.