System‐wide characterization of <scp>bZIP</scp> transcription factor proteins involved in infection‐related morphogenesis of <scp><i>M</i></scp><i>agnaporthe oryzae</i>

Self Cite

Summary In the rice blast fungus Magnaporthe oryzae, the cell wall integrity (CWI) signalling pathway governs cell wall changes in response to external cues and normal CWI signalling is critical for appressorium function and pathogenicity. We previously characterized the mitogen-activated protein kinase (MAPK) kinase MoMkk1 as an integral component of the CWI pathway. Using the affinity purification approach, we have identified MoMkk1-interacting MoPpe1 as a homologue of Saccharomyces cerevisiae serine/threonine protein phosphatase Sit4/Ppe1. We found that MoPpe1 is required for vegetative growth, conidiation and full virulence. In addition, we found that MoPpe1 interacts with MoSap1, a protein with functions similar to MoPpe1. Intriguingly, we found that MoPpe1–MoSap1 interaction is related to CWI and target of rapamycin (TOR) pathways. We presented evidence suggesting that MoPpe1 and MoSap1 function as an adaptor complex linking CWI and TOR signalling and that the activation of the TOR pathway leads to suppression of CWI signalling, resulting in defects in appressorium function and pathogenicity. Taken together, our studies not only reveal important functions of MoMkk1–MoPpe1–MoSap1 interactions in growth and pathogenicity of the blast fungus, but also highlight the complexity of regulatory networks involving conserved yet novel regulatory mechanisms of CWI and TOR signalling.

Section: Resultsmentioning

confidence: 99%

MoPpe1 partners with MoSap1 to mediate TOR and cell wall integrity signalling in growth and pathogenicity of the rice blast fungus Magnaporthe oryzae

Liu

Jia

Cai

et al. 2018

Self Cite

“…By using DTT as an ER stress inducer, we demonstrated that MoGlo3 has a role in the ER stress response. In addition, we showed that MoGlo3 has a role in the UPR pathway mediated by MoHac1 and MoMck1 (Tang et al ., ; Yin et al ., ). Since ER stress is hypothesized to occur during infection and invasive hyphae growth and that the fully functional UPR is required for penetration and invasive hyphae growth (Tang et al ., ), the perturbed UPR pathway under ER stress in the Δ Moglo3 mutant might foretell a defect in pathogenicity.…”

Section: Discussionmentioning

confidence: 99%

The ArfGAP protein MoGlo3 regulates the development and pathogenicity of Magnaporthe oryzae

Zhang

Liu

et al. 2017

Self Cite

The ADP ribosylation factor (Arf) and the coat protein complex I (COPI) are both involved in vesicle transport. Together with GTPase-activating proteins (ArfGAPs) and guanine exchange factors (ArfGEFs) that regulate the activity of Arf, they govern vesicle formation, COPI trafficking, and the maintenance of the Golgi complex. In an ongoing effort to study the role of membrane trafficking in pathogenesis of the rice blast fungus Magnaporthe oryzae, we identified MoGlo3 as an ArfGAP protein that is homologous to Glo3p of the budding yeast Saccharomyces cerevisiae. As suspected, MoGlo3 partially complements the function of yeast Glo3p. Consistent with findings in S. cerevisiae, MoGlo3 is localized to the Golgi and that the localization is dependent on the conserved BoCCS domain. We found that MoGlo3 is highly expressed during conidiation and early infection stages, and is required for vegetative growth, conidial production, and sexual development. We further found that the ΔMoglo3 mutant is defective in endocytosis, scavenging of the reactive oxygen species (ROS), and in the response to endoplasmic reticulum (ER) stress. The combined effects result in failed appressorium function and decreased pathogenicity. Moreover, we provided evidence showing that the domains including the GAP, BoCCS and GRM are all important for normal MoGlo3 functions. Our studies further illustrate the importance of normal membrane trafficking in the physiology and pathogenicity of the rice blast fungus.

“…2). The bZIP TFs represent one of the largest TF families among the eukaryotes and may regulate a broad range of biological processes including hyphal growth, virulence in pathogenic fungi and responses to oxidative stress (Kong et al, 2015;Tang et al, 2015).…”

Section: Discussionmentioning

confidence: 99%

Insights into VdCmr1‐mediated protection against high temperature stress and UV irradiation in Verticillium dahliae

Fang

Klosterman

Tian

et al. 2019

Summary The fungus Verticillium dahliae causes vascular wilt disease on more than 200 plant species worldwide. This fungus can survive for years in soil as melanized microsclerotia. We found that VdCmr1, a transcription factor, is required for the melanin production and increased survival following UV irradiation in V. dahliae but not for microsclerotia production or virulence. Here, we provided evidence how VdCmr1 protects against high temperature (HT) and UV irradiation in V. dahliae. The results indicate that VdCmr1 mediates entry to the diapause period in V. dahliae in response to HT and contributes to the expression of proteins to minimize protein misfolding and denaturation. VdCmr1 deletion results in the misregulation of DNA repair machinery, suggestive of reduced DNA repair capacity following UV irradiation and in correlation with the low survival rate of UV‐treated VdCmr1 mutants. We discovered a putative VdCmr1‐dependent gene cluster associated with secondary metabolism and stress responses. We also functionally characterized two VdCmr1‐responsive genes participating in HT and UV response. These results shed further light on the roles of VdCmr1 in protection from HT or UV irradiation, and the additional insights into the mechanisms of this protection may be useful to exploit for more effective disease control.