Functional Characterization of the M36 Metalloprotease FgFly1 in Fusarium graminearum

Abstract

Fungalysin metallopeptidase (M36), a hydrolase, catalyzes the hydrolysis of alanine, glycine, etc. Normally, it is considered to play an important role in the progress of fungal infection. However, the function of fungalysin metallopeptidase (M36) in Fusarium graminearum has not been reported. In this study, we explored the biological functions of FgFly1, a fungalysin metallopeptidase (M36) of F. graminearum. We found that ΔFgFly1 did not affect the ability to produce DON toxin, although it inhibited spore germination during asexual reproduction and reduction in pathogenicity compared with PH-1. Therefore, we speculated that FgFly1 affects the pathogenicity of F.graminearum by affecting pathways related to wheat disease resistance. Target protein TaCAMTA (calmodulin-binding transcription activator) was selected by a yeast two-hybrid (Y2H) system. Then, the interaction between FgFly1 and TaCAMTA was verified by bimolecular fluorescent complimentary (BiFC) and luciferase complementation assay (LCA). Furthermore, compared with wild-type Arabidopsis thaliana, the morbidity level of ΔAtCAMTA was increased after infection with F.graminearum, and the expression level of NPR1 was significantly reduced. Based on the above results, we concluded that FgFly1 regulated F. graminearum pathogenicity by interacting with host cell CAMTA protein.

Protein Disulfide Isomerase FgEps1 Is a Secreted Virulence Factor in Fusarium graminearum

“…During the coevolution of plants and pathogens, a complex interaction relationship develops. Plants have evolved various recognition and resistance mechanisms to organize and limit pathogen infection, while pathogens have developed diverse pathogenic mechanisms to avoid or overcome plant resistance mechanisms [37]. So far, we have only confirmed that FgEps1 is involved in the pathogenesis of F. graminearum but have not yet analyzed its mode of action in this process.…”

“…Once the aerial mycelium had grown over the culture dish, the aerial mycelium was scraped off, and 500 µL of 2.5% Tween-20 solution was added. The dish was then incubated for 15 days at 25 • C, alternating between dark and light cycles every 12 h [37]. The ascospore shell and ascospore morphology were observed under the light microscope.…”

Svx Peptidases of Phytopathogenic Pectolytic Bacteria: Structural, Catalytic and Phytoimmune Properties

“…Among the virulence factors of phytopathogenic microorganisms, many proteins with metallopeptidase activity have been described [44][45][46][47][48][49][50][51][52][53][54]. Most of these virulencerelated metallopeptidases are considered "instruments" of brute force that contribute to the disintegration of plant tissues, providing non-specific, extensive digestion of host proteins [45,46].…”

“…Herewith, in the presence of the specific host R protein, Avr-Pita acts as a race-specific elicitor that triggers a hypersensitive response associated with full plant resistance [53]. FgFly1 metallopeptidase from Fusarium graminearum interacts with the calmodulin-binding transcription activator, inhibiting the SA-mediated immune response [54].…”