Microbial degradation is an environmentally sustainable approach to mitigate autotoxicity induced by phenolic acids in agricultural systems. However, multiple phenolic acids coexist and interact in the environment, which greatly limits the application of microbes with the capacity to degrade a single phenolic acid. Here, Rhodococcus aetherivorans RA1, a novel and highly effective bacterium capable of degrading multiple phenolic acids, was firstly isolated from the rhizosphere soil of Dioscorea spp. Within 72 h, strain RA1 degraded > 90% of the mixed substrate with a total concentration of 1200 mg/L of ferulic acid, vanillic acid, and p -hydroxybenzoic acid. Strain RA1 also exhibited a strong degrading capacity for benzoic and caffeic acid, suggesting a broad substrate range. Furthermore, it exhibited excellent adaptability, maintaining high degradation rates (37 - 95%) over wide ranges of salinity (0 - 20 g/L NaCl) and temperature (10 - 43°C). Growth promoting assays indicated that it not only effectively alleviated the inhibitory effect of phenolic acids on the growth of Brassica rapa subsp. chinensis seeds, but also suppressed the growth of the pathogen Fusarium oxysporum by degrading phenolic acids. Whole-genome sequencing and analysis indicated that strain RA1 contains 23 phenolic acid degradation genes and a complex degradation network. This consisted of the peripheral pathways forming a multi-enzyme synergistic system and central degradation pathways composed of the protocatechuic acid 2,3-cleavage, 3,4-cleavage, and catechol pathways. Therefore, the effective degradation of phenolic acids by strain RA1 as a biological agent provides a biological resource for the application of microbes in agriculture. • Rhodococcus aetherivorans RA1 degrades 1200 mg/L mixed phenolic acids under stresses. • Strain RA1 exhibits versatile phenolic acid-degrading capabilities. • Strain RA1 reduces seed toxicity by degrading phenolic acids. • Strain RA1 suppresses the growth of pathogenic fungi promoted by phenolic acids. • Genome reveals a multi-branch phenolic acid degradation network in strain RA1.
Wang et al. (Wed,) studied this question.