Department of Environmental Microbiology and Biotechnology, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100 Toruń, Poland.
Department of Microbiology, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/C, H-1117 Budapest, Hungary.
FEMS Microbiol Ecol. 2023 Aug 22;99(9). doi: 10.1093/femsec/fiad093.
Chemical fertilization has a negative impact on the natural environment. Plant growth-promoting (PGP) rhizobacterial biofertilizers can be a safer alternative to synthetic agrochemicals. In this research, a culture-based method was used to assess the population size of rhizobacteria at the vegetative, flowering, and maturity stages of canola. Rhizobacteria were then isolated from each of the canola growth stages, and their seven PGP traits were determined. The highest abundance of culturable bacteria was found at the vegetative stage of the plants. Furthermore, four out of seven PGP traits were produced by the highest % of isolates at the vegetative stage. In the greenhouse experiment that included six rhizobacterial strains with best PGP traits, the greatest canola growth promotion ability under sterile conditions was observed after the introduction of Bacillus paralicheniformis 2R5. Moreover, under nonsterile conditions, 2R5 significantly increased canola growth. The presence of the trpA, B, C, D, E, F and pstA, and S genes in the 2R5 genome could be associated with canola growth promotion abilities. The chiA and mbtH genes could contribute to 2R5 antifungal activity against fungal pathogens. Moreover, the introduction of 2R5 significantly increased the abundance of the narG, nosZ, nifH, and nirS genes, which can prove that the 2R5 strain may be an important member of the soil bacterial community.
化学施肥对自然环境有负面影响。植物促生（PGP）根际细菌生物肥料可以作为合成农用化学品的更安全替代品。在这项研究中，使用基于培养的方法来评估油菜在营养生长、开花和成熟阶段的根际细菌种群大小。然后从油菜的每个生长阶段分离根际细菌，并确定它们的七种 PGP 特性。在植物的营养生长阶段发现了可培养细菌的最高丰度。此外，在营养生长阶段，有 4 种特性是由最高比例的分离株产生的。在包括具有最佳 PGP 特性的六种根际细菌菌株的温室实验中，在引入芽孢杆菌 paralicheniformis 2R5 后，在无菌条件下观察到油菜生长促进能力最强。此外，在非无菌条件下，2R5 显著增加了油菜的生长。2R5 基因组中 trpA、B、C、D、E、F 和 pstA、S 基因的存在可能与油菜生长促进能力有关。chiA 和 mbtH 基因可能有助于 2R5 对真菌病原体的抗真菌活性。此外，2R5 的引入显著增加了 narG、nosZ、nifH 和 nirS 基因的丰度，这可以证明 2R5 菌株可能是土壤细菌群落的重要成员。
