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Zhao X, Fan Y, Zhang L, Zhang W, Xiang M, Kang S, Wang S, Liu X. Multiple Roles of the Low-Affinity Calcium Uptake System in Drechslerella dactyloides, a Nematode-Trapping Fungus That Forms Constricting Rings. J Fungi (Basel) 2023; 9:975. [PMID: 37888231 PMCID: PMC10607529 DOI: 10.3390/jof9100975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 09/26/2023] [Accepted: 09/27/2023] [Indexed: 10/28/2023] Open
Abstract
(1) Background: the low-affinity calcium uptake system (LACS) has been shown to play a crucial role in the conidiation and formation of adhesive nets and knobs by nematode-trapping fungi (NTF), but its involvement in the formation of constricting rings (CRs), mechanical traps to capture free-living nematodes, remains unexplored. (2) Methods: we investigated the function of two LACS genes (DdaFIG_1 and DdaFIG_2) in Drechslerella dactyloides, an NTF that forms CRs. We generated single (DdaFIG_1Ri and DdaFIG_2Ri) and double (DdaFIG_1,2Ri) knockdown mutants via the use of RNA interference (RNAi). (3) Results: suppression of these genes significantly affected conidiation, trap formation, vegetative growth, and response to diverse abiotic stresses. The number of CRs formed by DdaFIG_1Ri, DdaFIG_2Ri, and DdaFIG_1,2Ri decreased to 58.5%, 59.1%, and 38.9% of the wild-type (WT) level, respectively. The ring cell inflation rate also decreased to 73.6%, 60.6%, and 48.8% of the WT level, respectively. (4) Conclusions: the LACS plays multiple critical roles in diverse NTF.
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Affiliation(s)
- Xiaozhou Zhao
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Science, Nankai University, Tianjin 300071, China
| | - Yani Fan
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Liao Zhang
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Science, Nankai University, Tianjin 300071, China
| | - Weiwei Zhang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Meichun Xiang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Seogchan Kang
- Department of Plant Pathology & Environmental Microbiology, The Pennsylvania State University, University Park, PA 16802, USA;
| | - Shunxian Wang
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Science, Nankai University, Tianjin 300071, China
| | - Xingzhong Liu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Science, Nankai University, Tianjin 300071, China
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Chen Y, Liu J, Fan Y, Xiang M, Kang S, Wei D, Liu X. SNARE Protein DdVam7 of the Nematode-Trapping Fungus Drechslerella dactyloides Regulates Vegetative Growth, Conidiation, and the Predatory Process via Vacuole Assembly. Microbiol Spectr 2022; 10:e0187222. [PMID: 36287065 PMCID: PMC9769606 DOI: 10.1128/spectrum.01872-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 09/30/2022] [Indexed: 01/07/2023] Open
Abstract
Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins play conserved roles in membrane fusion events in eukaryotes and have been documented to be involved in fungal growth and pathogenesis. However, little is known about the roles of SNAREs in trap morphogenesis in nematode-trapping fungi (NTF). Drechslerella dactyloides, one of the constricting ring-forming NTF, captures free-living nematodes via rapid ring cell inflation. Here, we characterized DdVam7 of D. dactyloides, a homolog of the yeast SNARE protein Vam7p. Deletion of DdVam7 significantly suppressed vegetative growth and conidiation. The mutation significantly impaired trap formation and ring cell inflation, resulting in a markedly decreased nematode-trapping ability. A large vacuole could develop in ring cells within ~2.5 s after instant inflation in D. dactyloides. In the ΔDdVam7 mutant, the vacuoles were small and fragmented in hyphae and uninflated ring cells, and the large vacuole failed to form in inflated ring cells. The localization of DdVam7 in vacuoles suggests its involvement in vacuole fusion. In summary, our results suggest that DdVam7 regulates vegetative growth, conidiation, and the predatory process by mediating vacuole assembly in D. dactyloides, and this provides a basis for studying mechanisms of SNAREs in NTF and ring cell rapid inflation. IMPORTANCE D. dactyloides is a nematode-trapping fungus that can capture nematodes through a constricting ring, the most sophisticated trapping device. It is amazing that constricting ring cells can inflate to triple their size within seconds to capture a nematode. A large centrally located vacuole is a unique signature associated with inflated ring cells. However, the mechanism underpinning trap morphogenesis, especially vacuole dynamics during ring cell inflation, remains unclear. Here, we documented the dynamics of vacuole assembly during ring cell inflation via time-lapse imaging for the first time. We characterized a SNARE protein in D. dactyloides (DdVam7) that was involved in vacuole assembly in hyphae and ring cells and played important roles in vegetative growth, conidiation, trap morphogenesis, and ring cell inflation. Overall, this study expands our understanding of biological functions of the SNARE proteins and vacuole assembly in NTF trap morphogenesis and provides a foundation for further study of ring cell rapid inflation mechanisms.
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Affiliation(s)
- Yue Chen
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Science, Nankai University, Tianjin, China
| | - Jia Liu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Science, Nankai University, Tianjin, China
| | - Yani Fan
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Meichun Xiang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Seogchan Kang
- Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, State College, Pennsylvania, USA
| | - Dongsheng Wei
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Science, Nankai University, Tianjin, China
| | - Xingzhong Liu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Science, Nankai University, Tianjin, China
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