The transcription factor FgCrz1A is essential for fungal development, virulence, deoxynivalenol biosynthesis and stress responses in Fusarium graminearum

Abstract

The zinc finger transcription factor Crz1 is an important downstream regulator of calcium-dependent signal transduction pathways in many organisms. The function of Crz1 in the wheat-head blight pathogen Fusarium graminearum remains unclear. In this study, we identified and functionally characterised FgCrz1A, a potential ortholog of yeast Crz1. The deletion mutant ΔFgCrz1A exhibited slower hyphal growth on basic medium, and conidia formation and sexual reproduction were completely blocked. ΔFgCrz1A also displayed increased sensitivity to metal cations Ca, Mg, Mn and Li, but decreased sensitivity to Zn. Unexpectedly, the deletion mutant was more resistant to osmotic stress and cell wall-damaging agents than the wild-type fungus. Pathogenicity assays showed that virulence of the mutant was dramatically decreased on flowering wheat heads and corn silks, consistent with the observed reduction in deoxynivalenol production. Moreover, GFP-fused FgCrz1A was mainly localised in the nucleus, and was required for transcriptional induction of abaA and wetA that are involved in conidiogenesis, as well as genes of the MAT locus during sexual reproduction, and TRI genes responsible for deoxynivalenol biosynthesis. Taken together, the results indicate that FgCrz1A plays critical roles not only in regulating fungal development, secondary metabolism and virulence in F. graminearum, but also in multiple stress responses.

The bZIP transcription factor FpAda1 is essential for fungal growth and conidiation in Fusarium pseudograminearum

“…MpAtf1 regulated the transcription of laccases and peroxidases, which was critical in pathogenicity (Guo et al 2010). In F. graminearum, transcription factors related to growth, development, stress responses and virulence were reported (Chen et al 2019b;Lv et al 2019). However, few transcription factors have been described in F. pseudograminearum.…”

Azaphilones biosynthesis complements the defence mechanism of Trichoderma guizhouense against oxidative stress

“…Thereby, oxidative stress seems to have been a key player in the evolution of fungal secondary metabolism (Roze et al ., 2011; Montibus et al ., 2015). In fact, stimulation of SMs formation by oxidative stress and ROS formation has recently been reported in several fungi, such as aflatoxin production by A. parasiticus , ochratoxin A formation by A. ochraceus , deoxynivalenol formation by F. graminearum and sterigmatocystin formation in Podospora anserina (Jayashree and Subramanyam, 2000; Reverberi et al ., 2012; Chen et al ., 2019; Shen et al ., 2019). In P. anserina , SMs were considered to function as a supplemental source of antioxidant protection, which enhance stress tolerance along with antioxidant enzyme gene expression (Shen et al ., 2019).…”

Ubiquitin E3 Ligase AaBre1 Responsible for H2B Monoubiquitination Is Involved in Hyphal Growth, Conidiation and Pathogenicity in Alternaria alternata

“…The RNA sequencing data acquired here indicated that genes encoding certain transcription factors were significantly down-regulated in strains lacking a functional copy of AaBre1. The loss of the C2H2-type transcription factor has been documented to compromise hyphal growth, conidial formation and virulence in Phytophthora sojae [40], Aspergillus fumigatus [41], Verticillium dahlia [42], Ustilago maydis [43], and Fusarium graminearum [44]. Three genes identified as likely members of the C2H2 family (since they harbored both tandemly arranged C2H2 zinc-finger domains and a nuclear localization signal) were suppressed in the ∆AaBre1 mutant strain.…”