Bacillus sp. B55 Restored the Normal Growth of cucumber seedlings and Altered the Soil Bacterial Community in Ferulic acid and P-coumaric acid-treated soils

The Bacillus sp. B55 were isolated from cucumber root litter using a M9 agar medium containing ferulic acid or p-coumaric acid as sole carbon source, and its degradation rates of ferulic acid and p-coumaric acid were 81.92% and 72.41% in LB solution, respectively. B55 had plant growth-promoting attributes including solubilization of inorganic phosphate, and production of siderophore and indole acetic acid (IAA). Both ferulic acid and p-coumaric acid significantly restrained an increase in cucumber seedling dry biomass, while the B55 inoculation not only completely counteracted the damage of phenolic acids to cucumber seedlings and decreased the content of ferulic acid and p-coumaric acid in soil, but also promoted cucumber seedlings growth. Amplicon sequencing found that B55 inoculation altered the cucumber rhizosphere bacterial community structure and promoted the enrichment of certain bacteria, such as Pseudomonas, Arthrobacter, Bacillus, Flavobacterium, Streptomyces and Comamonas.