c-di-GMP Regulates Various Phenotypes and Insecticidal Activity of Gram-Positive Bacillus thuringiensis

Abstract

C-di-GMP has been well investigated to play significant roles in the physiology of many Gram-negative bacteria. However, its effect on Gram-positive bacteria is less known. In order to more understand the c-di-GMP functions in Gram-positive bacteria, we have carried out a detailed study on the c-di-GMP-metabolizing enzymes and their physiological functions in Bacillus thuringiensis, a Gram-positive entomopathogenic bacterium that has been applied as an insecticide successfully. We performed a systematic study on the ten putative c-di-GMP-synthesizing enzyme diguanylate cyclases (DGCs) and c-di-GMP-degrading enzyme phosphodiesterases (PDEs) in B. thuringiensis BMB171, and artificially elevated the intracellular c-di-GMP level in BMB171 by deleting one or more pde genes. We found increasing level of intracellular c-di-GMP exhibits similar activities as those in Gram-negative bacteria, including altered activities in cell motility, biofilm formation, and cell-cell aggregation. Unexpectedly, we additionally found a novel function exhibited by the increasing level of c-di-GMP to promote the insecticidal activity of this bacterium against Helicoverpa armigera. Through whole-genome transcriptome profile analyses, we found that 4.3% of the B. thuringiensis genes were differentially transcribed when c-di-GMP level was increased, and 77.3% of such gene products are involved in some regulatory pathways not reported in other bacteria to date. In summary, our study represents the first comprehensive report on the c-di-GMP-metabolizing enzymes, their effects on phenotypes, and the transcriptome mediated by c-di-GMP in an important Gram-positive bacterium.

2‐Methylcitrate cycle: a well‐regulated controller of Bacillus sporulation

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“…The RNA integrity value (RIN) was then measured using an RNA 6000 Pico LabChip of Agilent 2100 Bioanalyzer (Agilent, Santa Clara, CA, USA). Removal of rRNA, construction of cDNA libraries and Illumina Sequencing were carried out as described (Su et al, 2016;Li et al, 2017;Fu et al, 2018).…”

Role of hsp20 in the Production of Spores and Insecticidal Crystal Proteins in Bacillus thuringiensis

“…For the extraction of the ICPs, the strains were grown under the GYS medium for 20 h, when cells started to lyse, 20 mL of each culture was separately collected. The procedures for extracting ICPs were performed according to previous studies (Wang X. et al, 2016; He et al, 2018). Finally, the ICPs were visualized by SDS-PAGE, and the ICPs concentrations were measured by the Bradford method.…”

A c-di-AMP riboswitch controlling kdpFABC operon transcription regulates the potassium transporter system in Bacillus thuringiensis

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