Overexpression of the CORVET complex alleviates the fungicidal effects of fludioxonil on the yeast Saccharomyces cerevisiae expressing hybrid histidine kinase 3

et al. 2020

New Phytologist

The fungus Verticillium dahliae causes vascular wilt disease on hundreds of plant species. Homologs of the bZIP transcription factor Atf1 are required for virulence in most pathogenic fungi, but the molecular basis for their involvement is largely unknown.We performed targeted gene deletion, expression analysis, biochemistry and pathogenicity assays to demonstrate that VdAtf1 governs pathogenesis via the regulation of nitrosative resistance and nitrogen metabolism in V. dahliae.VdAtf1 controls pathogenesis via the regulation of nitric oxide (NO) resistance and inorganic nitrogen metabolism rather than oxidative resistance and is important for penetration peg formation in V. dahliae. VdAtf1 affects ammonium and nitrate assimilation in response to various nitrogen sources. VdAtf1 may be involved in regulating the expression of VdNut1. VdAtf1 responds to NO stress by strengthening the fungal cell wall, and by causing over-accumulation of methylglyoxal and glycerol, which in turn impacts NO detoxification. We also verified that the VdAtf1 ortholog in Fusarium graminearum mediates nitrogen metabolism, suggesting conservation of this function in related plant pathogenic fungi.Our findings revealed new functions of VdAtf1 in pathogenesis, response to nitrosative stress and nitrogen metabolism in V. dahliae. The results provide novel insights into the regulatory mechanisms of the transcription factor VdAtf1 in virulence.

Section: Discussionmentioning

confidence: 99%

The bZIP transcription factor VdAtf1 regulates virulence by mediating nitrogen metabolism in Verticillium dahliae

et al. 2020

New Phytologist

“…Single deletion of VdSkn7 or double deletion of VdAtf1 and VdYap1 leads to its up‐regulation, causing abnormal glycerol accumulation. Over‐accumulation of intracellular glycerol may cause cell swelling, thereby leading to various morphological defects and ultimately growth inhibition (Randhawa et al ., 2019).…”

Section: Discussionmentioning

confidence: 99%

Convergent and distinctive functions of transcription factors VdYap1, VdAtf1, and VdSkn7 in the regulation of nitrosative stress resistance, microsclerotia formation, and virulence in Verticillium dahliae

Jin

Molecular Plant Pathology

et al. 2020

Vascular wilt disease caused by Verticillium dahliae impacts over 200 plant species worldwide and results in losses of agricultural production, as well as damage to ornamental plants and ecological habitats (Klosterman et al., 2009). In China, V. dahliae has not only posed a major threat to crop production, but has also taken a heavy toll on ornamental perennials like smoke trees (Cotinus coggygria), the leaves of which provide beautiful scenery at the Fragrant Hills Park in Beijing, China (Wang et al., 2013). V. dahliae penetrates plants through the roots via infectious hyphae that germinate from the long-lived soilborne microsclerotia (Fradin and Thomma, 2006; Klosterman et al., 2009). After penetration, the fungus continues to proliferate in the xylem, resulting in characteristic plant wilt symptoms (Beckman et al., 1976).

“…Over-accumulation of glycerol in the cell may lead to various morphological defects and ultimately growth inhibition, though its normal accumulation is a cellular adaptation to high osmotic stress and salt stress ( Randhawa et al, 2019 ). Fungi must maintain glycerol levels within limits suitable for growth, and tightly control its production and suppression ( Kayingo et al, 2001 ).…”

Section: Discussionmentioning

confidence: 99%

Transcriptome Variations in Verticillium dahliae in Response to Two Different Inorganic Nitrogen Sources

et al. 2021

Front. Microbiol.

The fungus Verticillium dahliae causes vascular wilt disease on hundreds of plant species. The main focus of the research to control this fungus has been aimed at infection processes such as penetration peg formation and effector secretion, but the ability of the fungus to acquire and utilize nutrients are often overlooked and may hold additional potential to formulate new disease control approaches. Little is known about the molecular mechanisms of nitrogen acquisition and assimilation processes in V. dahliae. In this present study, RNA sequencing and gene expression analysis were used to examine differentially expressed genes in response to the different nitrogen sources, nitrate and ammonium, in V. dahliae. A total of 3244 and 2528 differentially expressed genes were identified in response to nitrate and ammonium treatments, respectively. The data indicated nitrate metabolism requires additional energy input while ammonium metabolism is accompanied by reductions in particular cellular processes. Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses of DEGs during nitrate metabolism revealed that many of the genes encoded those involved in protein biosynthetic and metabolic processes, especially ribosome and RNA polymerase biosynthesis, but also other processes including transport and organonitrogen compound metabolism. Analysis of DEGs in the ammonium treatment indicated that cell cycle, oxidoreductase, and certain metabolic activities were reduced. In addition, DEGs participating in the utilization of both nitrate and ammonium were related to L-serine biosynthesis, energy-dependent multidrug efflux pump activity, and glycerol transport. We further showed that the mutants of three differentially expressed transcription factors (VdMcm1, VdHapX, and VDAG_08640) exhibited abnormal phenotypes under nitrate and ammonium treatment compared with the wild type strain. Deletion of VdMcm1 displayed slower growth when utilizing both nitrogen sources, while deletion of VdHapX and VDAG_08640 only affected nitrate metabolism, inferring that nitrogen assimilation required regulation of bZIP transcription factor family and participation of cell cycle. Taken together, our findings illustrate the convergent and distinctive regulatory mechanisms between preferred (ammonium) and alternative nitrogen (nitrate) metabolism at the transcriptome level, leading to better understanding of inorganic nitrogen metabolism in V. dahliae.