cAMP Signalling Pathway in Biocontrol Fungi

Abstract

Biocontrol is a complex process, in which a variety of physiological and biochemical characteristics are altered. The cAMP signalling pathway is an important signal transduction pathway in biocontrol fungi and consists of several key components. The G-protein system contains G-protein coupled receptors (GPCRs), heterotrimeric G-proteins, adenylate cyclase (AC), cAMP-dependent protein kinase (PKA), and downstream transcription factors (TFs). The cAMP signalling pathway can regulate fungal growth, development, differentiation, sporulation, morphology, secondary metabolite production, environmental stress tolerance, and the biocontrol of pathogens. However, few reviews of the cAMP signalling pathway in comprehensive biocontrol processes have been reported. This work reviews and discusses the functions and applications of genes encoding each component in the cAMP signalling pathway from biocontrol fungi, including the G-protein system components, AC, PKA, and TFs, in biocontrol behaviour. Finally, future suggestions are provided for constructing a complete cAMP signalling pathway in biocontrol fungi containing all the components and downstream effectors involved in biocontrol behavior. This review provides useful information for the understanding the biocontrol mechanism of biocontrol fungi by utilising the cAMP signalling pathway.

Keywords: G-protein system; adenylate cyclase; biocontrol; cAMP signalling pathway; cAMP-dependent protein kinase; transcription factor.

Figure 1

cAMP signalling pathway in biological control. GRCRs: G-protein coupled receptors; AC: Adenylate cyclase; PDE: Phosphodiesterase; PKA: cAMP-dependent protein kinase A; TFs: Transcription factors; CWDES: Cell-wall-degrading enzymes. Pathogen-related signals are transmitted into cells through GPCRs, activate G-proteins, and then stimulate AC. The activated AC converts ATP to cAMP, then, cAMP stimulates PKA, and finally, the activated PKA regulates the expression activities of downstream proteins, such as transcription factors, resulting in the biocontrol of pathogens.