Whole-Genome Metalloproteases in the Wheat Sharp Eyespot Pathogen <i>Rhizoctonia cerealis</i> and a Role in Fungal Virulence
<i>Rhizoctonia cerealis</i> is the causal agent of sharp eyespot, a devastating disease of cereal crops including wheat. Several metalloproteases have been implicated in pathogenic virulence, but little is known about whole-genome metalloproteases in <i>R. cerealis</i>. In th...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2022-09-01
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| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/23/18/10691 |
| Summary: | <i>Rhizoctonia cerealis</i> is the causal agent of sharp eyespot, a devastating disease of cereal crops including wheat. Several metalloproteases have been implicated in pathogenic virulence, but little is known about whole-genome metalloproteases in <i>R. cerealis</i>. In this study, a total of 116 metalloproteases-encoding genes were identified and characterized from the <i>R. cerealis</i> Rc207 genome. The gene expression profiles and phylogenetic relationship of 11 MEP36/fungalysin metalloproteases were examined during the fungal infection to wheat, and function of an upregulated secretory MEP36 named RcFL1 was validated. Of 11 MEP36 family metalloproteases, ten, except RcFL5, were predicted to be secreted proteins and nine encoding genes, but not <i>RcFL5</i> and <i>RcFL2</i>, were expressed during the <i>R. cerealis</i> infection process. Phylogenetic analysis suggested that MEP36 metalloproteases in <i>R. cerealis</i> were closely related to those of <i>Rhizoctonia solani</i> but were remote to those of <i>Bipolaris sorokiniana</i>, <i>Fusarium graminearum</i>, <i>F. pseudograminearum</i>, and <i>Pyricularia oryzae</i>. Expression of RcFL1 was significantly upregulated during the infection process and induced plant cell death in wheat to promote the virulence of the pathogen. The MEP36 domain was necessary for the activities of RcFL1. Furthermore, RcFL1 could repress the expression of wheat genes coding for the chitin elicitor receptor kinase TaCERK1 and chitinases. These results suggest that this MEP36 metalloprotease RcFL1 may function as a virulence factor of <i>R. cerealis</i> through inhibiting host chitin-triggered immunity and chitinases. This study provides insights on pathogenic mechanisms of <i>R. cerealis</i>. <i>RcFL1</i> likely is an important gene resource for improving resistance of wheat to <i>R. cerealis</i> through host-induced gene silencing strategy. |
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| ISSN: | 1661-6596 1422-0067 |