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Meng F, Tian C. Gene Family Expansion during the Adaptation of Colletotrichum gloeosporioides to Woody Plants. J Fungi (Basel) 2023; 9:1185. [PMID: 38132786 PMCID: PMC10744947 DOI: 10.3390/jof9121185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 12/08/2023] [Accepted: 12/08/2023] [Indexed: 12/23/2023] Open
Abstract
Gene gains/losses during evolution are critical for the adaptation of organisms to new environments or hosts. However, it remains unknown whether gene family expansions facilitated the adaptation of phytopathogenic fungi to woody plants. In this study, we compared the newly sequenced genome of the Colletotrichum gloeosporioides strain CFCC80308 with the genomes of two other C. gloeosporioides strains, Cg-14 and Lc-1, isolated from Persea americana and Liriodendron leaves, respectively. The genes in the expanded families, which were associated with plant surface signal recognition, encoded various proteins, including glycosyde hydrolases (GHs) and cytochrome P450. Interestingly, there was a substantial increase in the number of GH family genes in CFCC80308. Specifically, there were 368 enriched genes in the GH families (e.g., GH1, GH3, GH10, GH12, GH15, GH16, GH17, GH18, GH25, GH32, GH53, GH61, GH76, and GH81); the expression levels of these genes were highly up-regulated during the infection of poplar trees. Additionally, the GH17 family was larger in CFCC80308 than in C. gloeosporioides strains Cg-14 and Lc-1. Furthermore, the expansion of the MP65-encoding gene family during the adaptation of Colletotrichum species to woody plants was consistent with the importance of gene gains/losses for the adaptation of organisms to their environments. This study has clarified how C. gloeosporioides adapted to woody plants during evolution.
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Affiliation(s)
- Fanli Meng
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing 100083, China;
- Beijing Key Laboratory for Forest Pest Control, College of Forestry, Beijing Forestry University, Beijing 100083, China
| | - Chengming Tian
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing 100083, China;
- Beijing Key Laboratory for Forest Pest Control, College of Forestry, Beijing Forestry University, Beijing 100083, China
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Li H, Sheng RC, Zhang CN, Wang LC, Li M, Wang YH, Qiao YH, Klosterman SJ, Chen JY, Kong ZQ, Subbarao KV, Chen FM, Zhang DD. Two zinc finger proteins, VdZFP1 and VdZFP2, interact with VdCmr1 to promote melanized microsclerotia development and stress tolerance in Verticillium dahliae. BMC Biol 2023; 21:237. [PMID: 37904147 PMCID: PMC10617112 DOI: 10.1186/s12915-023-01697-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 09/08/2023] [Indexed: 11/01/2023] Open
Abstract
BACKGROUND Melanin plays important roles in morphological development, survival, host-pathogen interactions and in the virulence of phytopathogenic fungi. In Verticillum dahliae, increases in melanin are recognized as markers of maturation of microsclerotia which ensures the long-term survival and stress tolerance, while decreases in melanin are correlated with increased hyphal growth in the host. The conserved upstream components of the VdCmr1-regulated pathway controlling melanin production in V. dahliae have been extensively identified, but the direct activators of this pathway are still unclear. RESULTS We identified two genes encoding conserved C2H2-type zinc finger proteins VdZFP1 and VdZFP2 adjacent to VdPKS9, a gene encoding a negative regulator of both melanin biosynthesis and microsclerotia formation in V. dahliae. Both VdZFP1 and VdZFP2 were induced during microsclerotia development and were involved in melanin deposition. Their localization changed from cytoplasmic to nuclear in response to osmotic pressure. VdZFP1 and VdZFP2 act as modulators of microsclerotia melanization in V. dahliae, as confirmed by melanin biosynthesis inhibition and supplementation with the melanin pathway intermediate scytalone in albino strains. The results indicate that VdZFP1 and VdZFP2 participate in melanin biosynthesis by positively regulating VdCmr1. Based on the results obtained with yeast one- and two-hybrid (Y1H and Y2H) and bimolecular fluorescence complementation (BiFC) systems, we determined the melanin biosynthesis relies on the direct interactions among VdZFP1, VdZFP2 and VdCmr1, and these interactions occur on the cell walls of microsclerotia. Additionally, VdZFP1 and/or VdZFP2 mutants displayed increased sensitivity to stress factors rather than alterations in pathogenicity, reflecting the importance of melanin in stress tolerance of V. dahliae. CONCLUSIONS Our results revealed that VdZFP1 and VdZFP2 positively regulate VdCmr1 to promote melanin deposition during microsclerotia development, providing novel insight into the regulation of melanin biosynthesis in V. dahliae.
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Affiliation(s)
- Huan Li
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Ruo-Cheng Sheng
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Chen-Ning Zhang
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China
| | - Li-Chao Wang
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China
| | - Min Li
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China
| | - Ya-Hong Wang
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China
| | - Yu-Hang Qiao
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China
| | - Steven J Klosterman
- United States Department of Agriculture, Agricultural Research Service, Salinas, CA, USA
| | - Jie-Yin Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
- Western Agricultural Research Center, Chinese Academy of Agricultural Sciences, Changji, 831100, China
| | - Zhi-Qiang Kong
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
- Western Agricultural Research Center, Chinese Academy of Agricultural Sciences, Changji, 831100, China
| | - Krishna V Subbarao
- Department of Plant Pathology, University of California, Davis, c/o United States Agricultural Research Station,, Salinas, CA, USA.
| | - Feng-Mao Chen
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China.
| | - Dan-Dan Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
- Western Agricultural Research Center, Chinese Academy of Agricultural Sciences, Changji, 831100, China.
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Jeyaraj A, Elango T, Chen X, Zhuang J, Wang Y, Li X. Advances in understanding the mechanism of resistance to anthracnose and induced defence response in tea plants. MOLECULAR PLANT PATHOLOGY 2023; 24:1330-1346. [PMID: 37522519 PMCID: PMC10502868 DOI: 10.1111/mpp.13354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 05/03/2023] [Accepted: 05/04/2023] [Indexed: 08/01/2023]
Abstract
The tea plant (Camellia sinensis) is susceptible to anthracnose disease that causes considerable crop loss and affects the yield and quality of tea. Multiple Colletotrichum spp. are the causative agents of this disease, which spreads quickly in warm and humid climates. During plant-pathogen interactions, resistant cultivars defend themselves against the hemibiotrophic pathogen by activating defence signalling pathways, whereas the pathogen suppresses plant defences in susceptible varieties. Various fungicides have been used to control this disease on susceptible plants, but these fungicide residues are dangerous to human health and cause fungicide resistance in pathogens. The problem-solving approaches to date are the development of resistant cultivars and ecofriendly biocontrol strategies to achieve sustainable tea cultivation and production. Understanding the infection stages of Colletotrichum, tea plant resistance mechanisms, and induced plant defence against Colletotrichum is essential to support sustainable disease management practices in the field. This review therefore summarizes the current knowledge of the identified causative agent of tea plant anthracnose, the infection strategies and pathogenicity of C. gloeosporioides, anthracnose disease resistance mechanisms, and the caffeine-induced defence response against Colletotrichum infection. The information reported in this review will advance our understanding of host-pathogen interactions and eventually help us to develop new disease control strategies.
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Affiliation(s)
- Anburaj Jeyaraj
- College of HorticultureNanjing Agricultural UniversityNanjingChina
| | | | - Xuan Chen
- College of HorticultureNanjing Agricultural UniversityNanjingChina
| | - Jing Zhuang
- College of HorticultureNanjing Agricultural UniversityNanjingChina
| | - Yuhua Wang
- College of HorticultureNanjing Agricultural UniversityNanjingChina
| | - Xinghui Li
- College of HorticultureNanjing Agricultural UniversityNanjingChina
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Gao J, Zhou S, Tang W, Wang J, Liu H, Zhang Y, Wang L, Li X, Liu Z. The velvet proteins CsVosA and CsVelB coordinate growth, cell wall integrity, sporulation, conidial viability and pathogenicity in the rubber anthracnose fungus Colletotrichum siamense. Microbiol Res 2023; 268:127290. [PMID: 36571920 DOI: 10.1016/j.micres.2022.127290] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 11/25/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022]
Abstract
Colletotrichum siamense, a member of Colletotrichum gloeosporioides complex species, is the primary pathogen causing rubber anthracnose, which leads to significant economic loss in natural rubber production. Velvet family proteins are fungal-specific proteins and play an essential role in regulating development and secondary metabolism. In this study, we characterized two velvet proteins CsVosA and CsVelB in C. siamense as the orthologs of VosA and VelB in Aspergillus nidulans. CsVosA is located in the nucleus, and CsVelB displays a localization in both the nucleus and the cytoplasm. Deleting CsvosA or CsvelB results in a slow growth rate, and the CsvelB-knockout mutants also exhibit low mycelial density. CsVosA and CsVelB are involved in regulating chitin metabolism and distribution, leading to the variation in the cell wall integrity of C. siamense. Furthermore, disruption of CsvosA or CsvelB can decrease conidial production and viability, and the ΔCsvosA and ΔCsvelB mutants also lose the ability to produce fruiting bodies. Pathogenicity assays show that deleting CsvosA or CsvelB can lower the virulence, and the two velvet genes are essential for the full virulence of C. siamense. Based on the results of the yeast two-hybrid analysis and bimolecular fluorescence complementation assays, CsVosA can interact with CsVelB and form the complex CsVosA-CsVelB in the conidia of C. siamense, which may play essential roles in maintaining the cell wall integrity and conidial viability. In addition, CsVelB is also involved in regulating melanin production of C. siamense. In conclusion, CsVosA and CsVelB regulate vegetative growth, cell wall integrity, asexual/sexual sporulation, conidial viability and virulence in C. siamense.
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Affiliation(s)
- Jing Gao
- School of Life Sciences, Hainan University, Haikou, China
| | | | - Wen Tang
- School of Life Sciences, Hainan University, Haikou, China; One Health Institute, Hainan University, Haikou, China
| | - Jinhong Wang
- School of Life Sciences, Hainan University, Haikou, China
| | - Huanqing Liu
- School of Life Sciences, Hainan University, Haikou, China
| | - Ying Zhang
- School of Life Sciences, Hainan University, Haikou, China
| | - Liya Wang
- School of Life Sciences, Hainan University, Haikou, China
| | - Xiaoyu Li
- School of Life Sciences, Hainan University, Haikou, China; One Health Institute, Hainan University, Haikou, China.
| | - Zhiqiang Liu
- School of Life Sciences, Hainan University, Haikou, China; One Health Institute, Hainan University, Haikou, China.
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The Putative C 2H 2 Transcription Factor VadH Governs Development, Osmotic Stress Response, and Sterigmatocystin Production in Aspergillus nidulans. Cells 2022; 11:cells11243998. [PMID: 36552763 PMCID: PMC9776899 DOI: 10.3390/cells11243998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 11/28/2022] [Accepted: 12/08/2022] [Indexed: 12/14/2022] Open
Abstract
The VosA-VelB hetero-dimeric complex plays a pivotal role in regulating development and secondary metabolism in Aspergillus nidulans. In this work, we characterize a new VosA/VelB-activated gene called vadH, which is predicted to encode a 457-amino acid length protein containing four adjacent C2H2 zinc-finger domains. Mutational inactivation of vosA or velB led to reduced mRNA levels of vadH throughout the lifecycle, suggesting that VosA and VelB have a positive regulatory effect on the expression of vadH. The deletion of vadH resulted in decreased asexual development (conidiation) but elevated production of sexual fruiting bodies (cleistothecia), indicating that VadH balances asexual and sexual development in A. nidulans. Moreover, the vadH deletion mutant exhibited elevated susceptibility to hyperosmotic stress compared to wild type and showed elevated production of the mycotoxin sterigmatocystin (ST). Genome-wide expression analyses employing RNA-Seq have revealed that VadH is likely involved in regulating more genes and biological pathways in the developmental stages than those in the vegetative growth stage. The brlA, abaA, and wetA genes of the central regulatory pathway for conidiation are downregulated significantly in the vadH null mutant during asexual development. VadH also participates in regulating the genes, mat2, ppgA and lsdA, etc., related to sexual development, and some of the genes in the ST biosynthetic gene cluster. In summary, VadH is a putative transcription factor with four C2H2 finger domains and is involved in regulating asexual/sexual development, osmotic stress response, and ST production in A. nidulans.
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Guo J, Zhou X, Xie F, Cao J, Liu S, Zhong J, Zhu H. Hypovirulence caused by mycovirus in Colletotrichum fructicola. FRONTIERS IN PLANT SCIENCE 2022; 13:1038781. [PMID: 36275531 PMCID: PMC9585321 DOI: 10.3389/fpls.2022.1038781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 09/26/2022] [Indexed: 06/16/2023]
Abstract
Colletotrichum fructicola is a pathogenic fungus causing leaf black spot and fruit rot disease in a wide variety of crops. Some mycoviruses that cause detrimental effects on fungal hosts could be useful in studying the pathogenesis of fungal hosts. In this study, we reported two mycoviruses, Colletotrichum fructicola ourmia-like virus 1- Colletotrichum gloeosporioides ourmia-like virus 1 (CfOLV1-CgOLV1) and Colletotrichum fructicola ourmia-like virus 2 (CfOLV2), from a C. fructicola fungus. The complete genome sequences of CfOLV1-CgOLV1 and CfOLV2 contain 2,516 bp and 2,048 bp, respectively. Both of these viruses contain only one open reading frame (ORF), which encodes an RNA-dependent RNA polymerase (RdRp). CfOLV1-CgOLV1 was identical as the previously reported virus CgOLV1. Phylogenetic analysis showed that CfOLV2 is closely related to Scleroulivirus and Magoulivirus in the family Botourmiaviridae. Virus elimination and horizontal transmission experiments proved that the associated mycoviruses could reduce the pathogenicity of the host C. fructicola. In addition, we found that the virus-containing strains showed a much higher percentage of appressorium formation and more melanin production compared to isogenic virus-free strain, and the presence of the virus is detrimental to the growth of host fungi and regulates the integrity of the cell wall. Transcriptomic analysis showed that mycovirus infection caused various abnormal genes expression in C. fructicola. To the best of our knowledge, this is the first report of a hypovirulence-associated ourmia-like mycovirus in C. fructicola.
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Affiliation(s)
| | | | | | | | | | - Jie Zhong
- *Correspondence: Hongjian Zhu, ;Jie Zhong,
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Liu W, Han L, Chen J, Liang X, Wang B, Gleason ML, Zhang R, Sun G. The CfMcm1 Regulates Pathogenicity, Conidium Germination, and Sexual Development in Colletotrichum fructicola. PHYTOPATHOLOGY 2022; 112:2159-2173. [PMID: 35502927 DOI: 10.1094/phyto-03-22-0090-r] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Glomerella leaf spot (GLS), caused by Colletotrichum fructicola, is a severe disease worldwide on apple, causing defoliation, leaf and fruit spot, and substantial yield loss. However, little is known about its molecular mechanisms of pathogenesis. Previous transcriptome analysis revealed that a transcription factor, CfMcm1, was induced during leaf infection. In the present work, expression pattern analysis verified that the CfMcm1 gene was strongly expressed in conidia and early infection. Phenotypic analysis revealed that the gene deletion mutant ΔCfMcm1 lost pathogenicity to apple leaves by inhibiting conidial germination and appressorium formation. In addition to appressorium-mediated pathogenicity, ΔCfMcm1 colonization and hyphal extension in wounded apple fruit was also reduced, and conidial germination mode and conidial color were altered. ΔCfMcm1 displayed impairment of cell wall integrity and response to stress caused by oxidation, osmosis, and an acid environment. Furthermore, the deletion mutant produced fewer and smaller perithecia and no ascospores. In contrast, melanin deposition in mycelia of ΔCfMcm1 was strengthened. Further comparative transcriptome and quantitative PCR analysis revealed that CfMcm1 modulated expression of genes related to conidial development (CfERG5A, CfERG5B, CfHik5, and CfAbaA), appressorium formation (CfCBP1 and CfCHS7), pectin degradation (CfPelA and CfPelB), sexual development (CfMYB, CfFork, CfHMG, and CfMAT1-2-1), and melanin biosynthesis (CfCmr1, CfPKS1, CfT4HR1, CfTHR1, and CfSCD1). Our results demonstrated that CfMcm1 is a pivotal regulator possessing multiple functions in pathogenicity, asexual and sexual reproduction, and melanin biosynthesis.
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Affiliation(s)
- Wenkui Liu
- State Key Laboratory of Crop Stress Biology in Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi Province, 712100, China
| | - Lu Han
- State Key Laboratory of Crop Stress Biology in Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi Province, 712100, China
| | - Jinzhu Chen
- State Key Laboratory of Crop Stress Biology in Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi Province, 712100, China
| | - Xiaofei Liang
- State Key Laboratory of Crop Stress Biology in Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi Province, 712100, China
| | - Bo Wang
- State Key Laboratory of Crop Stress Biology in Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi Province, 712100, China
| | - Mark L Gleason
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA 50011, U.S.A
| | - Rong Zhang
- State Key Laboratory of Crop Stress Biology in Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi Province, 712100, China
| | - Guangyu Sun
- State Key Laboratory of Crop Stress Biology in Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi Province, 712100, China
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Li H, Wang D, Zhang DD, Geng Q, Li JJ, Sheng RC, Xue HS, Zhu H, Kong ZQ, Dai XF, Klosterman SJ, Subbarao KV, Chen FM, Chen JY. A polyketide synthase from Verticillium dahliae modulates melanin biosynthesis and hyphal growth to promote virulence. BMC Biol 2022; 20:125. [PMID: 35637443 PMCID: PMC9153097 DOI: 10.1186/s12915-022-01330-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 05/13/2022] [Indexed: 01/15/2023] Open
Abstract
Background During the disease cycle, plant pathogenic fungi exhibit a morphological transition between hyphal growth (the phase of active infection) and the production of long-term survival structures that remain dormant during “overwintering.” Verticillium dahliae is a major plant pathogen that produces heavily melanized microsclerotia (MS) that survive in the soil for 14 or more years. These MS are multicellular structures produced during the necrotrophic phase of the disease cycle. Polyketide synthases (PKSs) are responsible for catalyzing production of many secondary metabolites including melanin. While MS contribute to long-term survival, hyphal growth is key for infection and virulence, but the signaling mechanisms by which the pathogen maintains hyphal growth are unclear. Results We analyzed the VdPKSs that contain at least one conserved domain potentially involved in secondary metabolism (SM), and screened the effect of VdPKS deletions in the virulent strain AT13. Among the five VdPKSs whose deletion affected virulence on cotton, we found that VdPKS9 acted epistatically to the VdPKS1-associated melanin pathway to promote hyphal growth. The decreased hyphal growth in VdPKS9 mutants was accompanied by the up-regulation of melanin biosynthesis and MS formation. Overexpression of VdPKS9 transformed melanized hyphal-type (MH-type) into the albinistic hyaline hyphal-type (AH-type), and VdPKS9 was upregulated in the AH-type population, which also exhibited higher virulence than the MH-type. Conclusions We show that VdPKS9 is a powerful negative regulator of both melanin biosynthesis and MS formation in V. dahliae. These findings provide insight into the mechanism of how plant pathogens promote their virulence by the maintenance of vegetative hyphal growth during infection and colonization of plant hosts, and may provide novel targets for the control of melanin-producing filamentous fungi. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-022-01330-2.
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Du Y, Wang M, Zou L, Long M, Yang Y, Zhang Y, Liang X. Quantitative Detection and Monitoring of Colletotrichum siamense in Rubber Trees Using Real-Time PCR. PLANT DISEASE 2021; 105:2861-2866. [PMID: 33900111 DOI: 10.1094/pdis-10-20-2198-re] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Colletotrichum siamense is one of the most important pathogens of rubber trees in Asia. The proper detection and quantification of C. siamense populations in rubber trees are of importance for monitoring the epidemics of the disease. In this study, we developed an internal transcribed spacer-based real-time PCR method to efficiently detect C. siamense infecting rubber trees, which reliably detected as little as 100 fg of genomic DNA, 100 copies of target DNA, and 20 conidia. The real-time PCR protocol recognized all C. siamense isolates collected from three provinces in China, whereas no amplification was observed with the rubber tree and its other pathogens. Detection and quantification of C. siamense were performed in artificially and naturally infected rubber leaves. We could still detect C. siamense in plant mixes, of which only 0.0001% of the tissue was infected. An accumulation of C. siamense DNA was observed during the whole infection process at all three leaf phenological stages, suggesting that the real-time PCR method can be used to monitor C. siamense development in rubber trees. Finally, the method allowed the detection of C. siamense in naturally infected and symptomless leaves of rubber trees in the fields. Compared with earlier detection methods, the real-time PCR method is more specific and more sensitive, and it will be of great use for studies aiming to gain a better understanding of the epidemiology of Colletotrichum leaf disease, as well as the prediction of disease risk and proposals to control it.
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Affiliation(s)
- Yannan Du
- College of Plant Protection, Hainan University, Haikou 570228, China
| | - Meng Wang
- College of Plant Protection, Hainan University, Haikou 570228, China
- Natural Rubber Cooperative Innovation Center of Hainan Province, Ministry of Education, Haikou 570228, China
- Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests, Ministry of Education, Haikou 570228, China
| | - Lijun Zou
- College of Plant Protection, Hainan University, Haikou 570228, China
| | - Mingteng Long
- College of Plant Protection, Hainan University, Haikou 570228, China
| | - Ye Yang
- College of Plant Protection, Hainan University, Haikou 570228, China
- Natural Rubber Cooperative Innovation Center of Hainan Province, Ministry of Education, Haikou 570228, China
| | - Yu Zhang
- College of Plant Protection, Hainan University, Haikou 570228, China
- Natural Rubber Cooperative Innovation Center of Hainan Province, Ministry of Education, Haikou 570228, China
- Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests, Ministry of Education, Haikou 570228, China
| | - Xiaoyu Liang
- College of Plant Protection, Hainan University, Haikou 570228, China
- Natural Rubber Cooperative Innovation Center of Hainan Province, Ministry of Education, Haikou 570228, China
- Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests, Ministry of Education, Haikou 570228, China
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HapX, an Indispensable bZIP Transcription Factor for Iron Acquisition, Regulates Infection Initiation by Orchestrating Conidial Oleic Acid Homeostasis and Cytomembrane Functionality in Mycopathogen Beauveria bassiana. mSystems 2020; 5:5/5/e00695-20. [PMID: 33051379 PMCID: PMC7567583 DOI: 10.1128/msystems.00695-20] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Conidial maturation and germination are highly coupled physiological processes in filamentous fungi that are critical for the pathogenicity of mycopathogens. Compared to the mechanisms involved in conidial germination, those of conidial reserves during maturation are less understood. The insect-pathogenic fungus Beauveria bassiana, as a representative species of filamentous fungi, is important for applied and fundamental research. In addition to its conserved roles in fungal adaptation to iron status, the bZIP transcription factor HapX acts as a master regulator involved in conidial virulence and regulates fatty acid/lipid metabolism. Further investigation revealed that the Δ9-fatty acid desaturase gene (Ole1) is a direct downstream target of HapX. This study reveals the HapX-Ole1 pathway involved in the fatty acid/lipid accumulation associated with conidial maturation and provides new insights into the startup mechanism of infection caused by spores from pathogenic fungi. In pathogenic filamentous fungi, conidial germination not only is fundamental for propagation in the environment but is also a critical step of infection. In the insect mycopathogen Beauveria bassiana, we genetically characterized the role of the basic leucine zipper (bZIP) transcription factor HapX (BbHapX) in conidial nutrient reserves and pathogen-host interaction. Ablation of BbHapX resulted in an almost complete loss of virulence in the topical inoculation and intrahemocoel injection assays. Comparative transcriptomic analysis revealed that BbHapX is required for fatty acid (FA)/lipid metabolism, and biochemical analyses indicated that BbHapX loss caused a significant reduction in conidial FA contents. Exogenous oleic acid could partially or completely restore the impaired phenotypes of the ΔBbHapX mutant, including germination rate, membrane integrity, vegetative growth, and virulence. BbHapX mediates fungal iron acquisition which is not required for desaturation of stearic acid. Additionally, inactivation of the Δ9-fatty acid desaturase gene (BbOle1) generated defects similar to those of the ΔBbHapX mutant; oleic acid also had significant restorative effects on the defective phenotypes of the ΔBbOle1 mutant. A gel retarding assay revealed that BbHapX directly regulated the expression of BbOle1. Lipidomic analyses indicated that both BbHapX and BbOle1 contributed to the homeostasis of phospholipids with nonpolar tails derived from oleic acid; therefore, exogenous phospholipids could significantly restore membrane integrity. These data reveal that the HapX-Ole1 pathway contributes to conidial fatty acid/lipid reserves and that there are important links between the lipid biology and membrane functionality involved in the early stages of infection caused by B.bassiana. IMPORTANCE Conidial maturation and germination are highly coupled physiological processes in filamentous fungi that are critical for the pathogenicity of mycopathogens. Compared to the mechanisms involved in conidial germination, those of conidial reserves during maturation are less understood. The insect-pathogenic fungus Beauveria bassiana, as a representative species of filamentous fungi, is important for applied and fundamental research. In addition to its conserved roles in fungal adaptation to iron status, the bZIP transcription factor HapX acts as a master regulator involved in conidial virulence and regulates fatty acid/lipid metabolism. Further investigation revealed that the Δ9-fatty acid desaturase gene (Ole1) is a direct downstream target of HapX. This study reveals the HapX-Ole1 pathway involved in the fatty acid/lipid accumulation associated with conidial maturation and provides new insights into the startup mechanism of infection caused by spores from pathogenic fungi.
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Chen JF, Liu Y, Tang GR, Jin D, Chen X, Pei Y, Fan YH. The secondary metabolite regulator, BbSmr1, is a central regulator of conidiation via the BrlA-AbaA-WetA pathway in Beauveria bassiana. Environ Microbiol 2020; 23:810-825. [PMID: 32691932 DOI: 10.1111/1462-2920.15155] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 06/27/2020] [Accepted: 07/04/2020] [Indexed: 01/21/2023]
Abstract
The filamentous fungus Beauveria bassiana, an insect fungal pathogen, is widely used for pest biocontrol. Aerial conidia are infectious propagules, and their yield and viability greatly affect the field application of this fungus; however, little is known about the molecular regulatory mechanism of the triggered conidiation. In the present study, we find that the secondary metabolite regulator BbSmr1 is involved in the regulation of asexual conidiation development and stress response in B. bassiana. A deficiency in Bbsmr1 results in a prominent fluffy-like phenotype on solid medium, decreased conidial yield, accelerated conidial germination, as well as increased tolerance to H2 O2 stress and cell wall inhibitors. The deletion of Bbsmr1 also leads to thickened conidial cell walls and changed cell epitopes. Overexpressing either BbbrlA or BbabaA in the ∆Bbsmr1 strain can rescue the phenotypes of conidial development and stress response. BbSmr1 activates BbbrlA transcription by directly binding to the A4GA3 sequence of the BbbrlA promoter. BbBrlA in turn binds to the promoter of Bbsmr1 and negatively regulates the expression of Bbsmr1. These results indicate that BbSmr1 positively regulates conidial development in B. bassiana by activating the central development pathway BrlA-AbaA-WetA and provides insights into the developmental regulatory mechanism of entomopathogenic fungi.
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Affiliation(s)
- Jin-Feng Chen
- State Key Laboratory of Silkworm Genome Biology, Biotechnology Research Center, Southwest University, Chongqing, 400716, China.,College of Biological and Chemical Engineering, Chongqing University of Education, Chongqing, 400067, China
| | - Yu Liu
- College of Biotechnology, Southwest University, Beibei, Chongqing, 400716, China
| | - Gui-Rong Tang
- State Key Laboratory of Silkworm Genome Biology, Biotechnology Research Center, Southwest University, Chongqing, 400716, China
| | - Dan Jin
- State Key Laboratory of Silkworm Genome Biology, Biotechnology Research Center, Southwest University, Chongqing, 400716, China
| | - Xi Chen
- State Key Laboratory of Silkworm Genome Biology, Biotechnology Research Center, Southwest University, Chongqing, 400716, China
| | - Yan Pei
- State Key Laboratory of Silkworm Genome Biology, Biotechnology Research Center, Southwest University, Chongqing, 400716, China
| | - Yan-Hua Fan
- State Key Laboratory of Silkworm Genome Biology, Biotechnology Research Center, Southwest University, Chongqing, 400716, China
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