The Fusarium graminearum FGSG_03624 Xylanase Enhances Plant Immunity and Increases Resistance against Bacterial and Fungal Pathogens

Abstract

Fungal enzymes degrading the plant cell wall, such as xylanases, can activate plant immune responses. The Fusarium graminearum FGSG_03624 xylanase, previously shown to elicit necrosis and hydrogen peroxide accumulation in wheat, was investigated for its ability to induce disease resistance. To this aim, we transiently and constitutively expressed an enzymatically inactive form of FGSG_03624 in tobacco and Arabidopsis, respectively. The plants were challenged with Pseudomonas syringae pv. tabaci or pv. maculicola and Botrytis cinerea. Symptom reduction by the bacterium was evident, while no reduction was observed after B. cinerea inoculation. Compared to the control, the presence of the xylanase gene in transgenic Arabidopsis plants did not alter the basal expression of a set of defense-related genes, and, after the P. syringae inoculation, a prolonged PR1 expression was detected. F. graminearum inoculation experiments of durum wheat spikes exogenously treated with the FGSG_03624 xylanase highlighted a reduction of symptoms in the early phases of infection and a lower fungal biomass accumulation than in the control. Besides, callose deposition was detected in infected spikes previously treated with the xylanase and not in infected control plants. In conclusion, our results highlight the ability of FGSG_03624 to enhance plant immunity, thus decreasing disease severity.

Secreted Glycoside Hydrolase Proteins as Effectors and Invasion Patterns of Plant-Associated Fungi and Oomycetes

“…Furthermore, the VdEG3-CBM domain also suppressed cell death triggered by GH12 proteins from other fungal species ( Gui et al, 2017 ). Of note, several other microbial GH proteins have been found to contain CBM domains ( Tundo et al, 2021 ; Takeda et al, 2022 ). These include MoCel10A and MoCel6A, a GH10 xylanase and GH6 cellobiohydrolase, respectively, from Magnaporthe oryzae , the hemibiotrophic fungal pathogen responsible for blast disease of rice ( Oryza sativa ).…”

Defense Mechanisms of Cotton Fusarium and Verticillium Wilt and Comparison of Pathogenic Response in Cotton and Humans

“…DCJ-A produces cyclic hexapeptide compounds that exhibit cytotoxic activity against five human tumor cells [ 189 ]. Xylanase produced by F. graminearum FGSG_03624 activates the immune response of plants and enhances their resistance to bacterial and fungal pathogens [ 190 ]. In addition, F. graminearum Ec220 produces a xylanase with low cellulase content when grown on wheat bran [ 191 ], which has good commercial prospects.…”

Advances in Fungal Elicitor-Triggered Plant Immunity

“…EIX (ethylene-inducing xylanase), identified in the nonpathogenic fungus Trichoderma viride originally, with β-1-4-endoglucanase activity, is an important class of elicitor in the GH11 family [ 31 ], and EIX-induced PTI immunity is not dependent on its enzymatic activity but the receptors LeEIX1 and LeEIX2 [ 32 ]. EIX homologues were isolated from plant pathogenic fungi, including B. cinerea , F. graminearum and V. dahliae , and FGSG_03624 from F. graminearum , BcXyn11A from B. cinerea , and VdEIX3, from V. dahliae also have the ability to trigger PTI immune responses and plant resistance to fungal infection [ 33 , 34 , 35 , 36 ]. In addition to GH11, other CWDEs-related GHs, including GH10, GH12, GH28, and GH45, have been proven to be fungal elicitors [ 37 , 38 ].…”