MaNmrA, a Negative Transcription Regulator in Nitrogen Catabolite Repression Pathway, Contributes to Nutrient Utilization, Stress Resistance, and Virulence in Entomopathogenic Fungus <i>Metarhizium acridum</i>
The NCR pathway plays an important regulatory role in the nitrogen metabolism of filamentous fungi. NmrA, a central negative regulatory protein in the NCR pathway and a key factor in sensing to the carbon metabolism, plays important roles in pathogenic fungal nutrition metabolism. In this study, we...
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| Autores principales: | , , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
MDPI AG
2021
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/712c5243974a48cb9a6d5684c2e39f0b |
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| Sumario: | The NCR pathway plays an important regulatory role in the nitrogen metabolism of filamentous fungi. NmrA, a central negative regulatory protein in the NCR pathway and a key factor in sensing to the carbon metabolism, plays important roles in pathogenic fungal nutrition metabolism. In this study, we characterized the functions of <i>MaNmrA</i> in the insect pathogenic fungus <i>M. acridum</i>. Multiple sequence alignments found that the conserved domain (NAD/NADP binding domain) of MaNmrA was highly conservative with its homologues proteins. Deletion of <i>MaNmrA</i> improved the utilization of multiple carbon sources (such as glucose, mannose, sucrose, and trehalose) and non-preferred nitrogen sources (such as NaNO<sub>3</sub> and urea), significantly delayed the conidial germination rate and reduced the conidial yield. The <i>MaNmrA</i>-disruption strain (Δ<i>MaNmrA</i>) significantly decreased tolerances to UV-B and heat-shock, and it also increased the sensitivity to the hypertonic substance sorbitol, oxygen stress substance H<sub>2</sub>O<sub>2</sub>, and cell wall destroyer calcofluor white, indicating that loss of <i>MaNmrA</i> affected cell wall integrity, tolerances to hypertonic and oxidative stress. Bioassays demonstrated that disruption of <i>MaNmrA</i> decreased the virulence in both topical inoculation and intrahemocoel injection tests. Further studies revealed that the appressorium formation, turgor pressure, and colonization in hemolymph were significantly reduced in the absence of <i>MaNmrA</i>. Our work will deepen the functional cognition of <i>MaNmrA</i> and make a contribution to the study of its homologous proteins. |
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