The Xanthomonas citri Reverse Fitness Deficiency by Activating a Novel β-Glucosidase Under Low Osmostress

Abstract

Bacteria can withstand various types of environmental osmostress. A sudden rise in osmostress affects bacterial cell growth that is countered by activating special genes. The change of osmostress is generally a slow process under the natural environment. However, the collective response of bacteria to low osmostress remains unknown. This study revealed that the deletion of phoP (ΔphoP) from X. citri significantly compromised the growth and virulence as compared to the wild-type strain. Interestingly, low osmostress reversed physiological deficiencies of X. citri phoP mutant related to bacterial growth and virulence. The results also provided biochemical and genetic evidence that the physiological deficiency of phoP mutant can be reversed by low osmostress induced β-glucosidase (BglS) expression. Based on the data, this study proposes a novel regulatory mechanism of a novel β-glucosidase activation in X. citri through low osmostress to reverse the fitness deficiency.

The recombination regulator RecX negatively regulates heat-stable antifungal factor (HSAF) biosynthesis in Lysobacter enzymogenes

“…Protein expression and purification were performed as previously reported (Li et al 2017(Li et al , 2021(Li et al , 2022. To clone the recX gene, genomic DNA extracted from L. enzymogenes was used for PCR amplification using Pfu DNA polymerase, and the primers are listed in Additional file 2: Table S2.…”

“…The inoculated cultures were then incubated at 28°C and 180 rpm. The cells were harvested to assess β-galactosidase activities according to previous studies (Wang et al 2019;Li et al 2020bLi et al , 2022Wang et al 2021).…”