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Park J, Han JW, Lee N, Kim S, Choi S, Lee HH, Kim JE, Seo YS, Choi GJ, Lee YW, Kim H, Son H. Sulfur metabolism-mediated fungal glutathione biosynthesis is essential for oxidative stress resistance and pathogenicity in the plant pathogenic fungus Fusarium graminearum. mBio 2024; 15:e0240123. [PMID: 38112432 PMCID: PMC10790779 DOI: 10.1128/mbio.02401-23] [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: 09/04/2023] [Accepted: 11/13/2023] [Indexed: 12/21/2023] Open
Abstract
IMPORTANCE Fusarium graminearum is a destructive fungal pathogen that causes Fusarium head blight (FHB) on a wide range of cereal crops. To control fungal diseases, it is essential to comprehend the pathogenic mechanisms that enable fungi to overcome host defenses during infection. Pathogens require an oxidative stress response to overcome host-derived oxidative stress. Here, we identify the underlying mechanisms of the Fgbzip007-mediated oxidative stress response in F. graminearum. ChIP-seq and subsequent genetic analyses revealed that the role of glutathione in pathogenesis is not dependent on antioxidant functions in F. graminearum. Altogether, this study establishes a comprehensive framework for the Fgbzip007 regulon on pathogenicity and oxidative stress responses, offering a new perspective on the role of glutathione in pathogenicity.
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Affiliation(s)
- Jiyeun Park
- Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea
| | - Jae Woo Han
- Center for Eco-Friendly New Materials, Korea Research Institute of Chemical Technology, Daejeon, South Korea
| | - Nahyun Lee
- Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea
| | - Sieun Kim
- Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea
| | - Soyoung Choi
- Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea
| | - Hyun-Hee Lee
- Department of Integrated Biological Science, Pusan National University, Busan, South Korea
| | - Jung-Eun Kim
- Research Institute of Climate Change and Agriculture, National Institute of Horticultural and Herbal Science, Jeju, South Korea
| | - Young-Su Seo
- Department of Integrated Biological Science, Pusan National University, Busan, South Korea
| | - Gyung Ja Choi
- Center for Eco-Friendly New Materials, Korea Research Institute of Chemical Technology, Daejeon, South Korea
- Department of Medicinal Chemistry and Pharmacology, University of Science and Technology, Daejeon, South Korea
| | - Yin-Won Lee
- Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea
| | - Hun Kim
- Center for Eco-Friendly New Materials, Korea Research Institute of Chemical Technology, Daejeon, South Korea
- Department of Medicinal Chemistry and Pharmacology, University of Science and Technology, Daejeon, South Korea
| | - Hokyoung Son
- Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
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Webb RJ, Rush C, Berger L, Skerratt LF, Roberts AA. Glutathione is required for growth and cadmium tolerance in the amphibian chytrid fungus, Batrachochytrium dendrobatidis. Biochimie 2023; 220:22-30. [PMID: 38104714 DOI: 10.1016/j.biochi.2023.12.002] [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: 05/08/2023] [Revised: 11/24/2023] [Accepted: 12/12/2023] [Indexed: 12/19/2023]
Abstract
Batrachochytrium dendrobatidis (Bd) is a lethal amphibian pathogen, partly due to its ability to evade the immune system of susceptible frog species. In many pathogenic fungi, the antioxidant glutathione is a virulence factor that helps neutralise oxidative stressors generated from host immune cells, as well as other environmental stressors such as heavy metals. The role of glutathione in stress tolerance in Bd has not been investigated. Here, we examine the changes in the glutathione pool after stress exposure and quantify the effect of glutathione depletion on cell growth and stress tolerance. Depletion of glutathione repressed growth and release of zoospores, suggesting that glutathione is essential for life cycle completion in Bd. Supplementation with <2 mM exogenous glutathione accelerated zoospore development, but concentrations >2 mM were strongly inhibitory to Bd cells. While hydrogen peroxide exposure lowered the total cellular glutathione levels by 42 %, glutathione depletion did not increase the sensitivity to hydrogen peroxide. Exposure to cadmium increased total cellular glutathione levels by 93 %. Glutathione-depleted cells were more sensitive to cadmium, and this effect was attenuated by glutathione supplementation, suggesting that glutathione plays an important role in cadmium tolerance. The effects of heat and salt were exacerbated by the addition of exogenous glutathione. The impact of glutathione levels on Bd stress sensitivity may help explain differences in host susceptibility to chytridiomycosis and may provide opportunities for synergistic therapeutics.
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Affiliation(s)
- Rebecca J Webb
- James Cook University, Townsville, QLD, 4811, Australia; Melbourne Veterinary School, University of Melbourne, Werribee, VIC, 3030, Australia.
| | | | - Lee Berger
- Melbourne Veterinary School, University of Melbourne, Werribee, VIC, 3030, Australia
| | - Lee F Skerratt
- Melbourne Veterinary School, University of Melbourne, Werribee, VIC, 3030, Australia
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3
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Sun B, Zhou R, Zhu G, Xie X, Chai A, Li L, Fan T, Li B, Shi Y. Transcriptome Analysis Reveals the Involvement of Mitophagy and Peroxisome in the Resistance to QoIs in Corynespora cassiicola. Microorganisms 2023; 11:2849. [PMID: 38137993 PMCID: PMC10745780 DOI: 10.3390/microorganisms11122849] [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: 10/20/2023] [Revised: 11/08/2023] [Accepted: 11/21/2023] [Indexed: 12/24/2023] Open
Abstract
Quinone outside inhibitor fungicides (QoIs) are crucial fungicides for controlling plant diseases, but resistance, mainly caused by G143A, has been widely reported with the high and widespread use of QoIs. However, two phenotypes of Corynespora casiicola (RI and RII) with the same G143A showed significantly different resistance to QoIs in our previous study, which did not match the reported mechanisms. Therefore, transcriptome analysis of RI and RII strains after trifloxystrobin treatment was used to explore the new resistance mechanism in this study. The results show that 332 differentially expressed genes (DEGs) were significantly up-regulated and 448 DEGs were significantly down-regulated. The results of GO and KEGG enrichment showed that DEGs were most enriched in ribosomes, while also having enrichment in peroxide, endocytosis, the lysosome, autophagy, and mitophagy. In particular, mitophagy and peroxisome have been reported in medicine as the main mechanisms of reactive oxygen species (ROS) scavenging, while the lysosome and endocytosis are an important organelle and physiological process, respectively, that assist mitophagy. The oxidative stress experiments showed that the oxidative stress resistance of the RII strains was significantly higher than that of the RI strains: specifically, it was more than 1.8-fold higher at a concentration of 0.12% H2O2. This indicates that there is indeed a significant difference in the scavenging capacity of ROS between the two phenotypic strains. Therefore, we suggest that QoIs' action caused a high production of ROS, and that scavenging mechanisms such as mitophagy and peroxisomes functioned in RII strains to prevent oxidative stress, whereas RI strains were less capable of resisting oxidative stress, resulting in different resistance to QoIs. In this study, it was first revealed that mitophagy and peroxisome mechanisms available for ROS scavenging are involved in the resistance of pathogens to fungicides.
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Affiliation(s)
| | | | | | | | | | | | | | - Baoju Li
- State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (B.S.); (R.Z.)
| | - Yanxia Shi
- State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (B.S.); (R.Z.)
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Canto-Canché B, Burgos-Canul YY, Chi-Chuc D, Tzec-Simá M, Ku-González A, Brito-Argáez L, Carrillo-Pech M, De Los Santos-Briones C, Canseco-Pérez MÁ, Luna-Moreno D, Beltrán-García MJ, Islas-Flores I. Moonlight-like proteins are actually cell wall components in Pseudocercospora fijiensis. World J Microbiol Biotechnol 2023; 39:232. [PMID: 37349471 DOI: 10.1007/s11274-023-03676-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Accepted: 06/12/2023] [Indexed: 06/24/2023]
Abstract
The fungal cell wall protects fungi against threats, both biotic and abiotic, and plays a role in pathogenicity by facilitating host adhesion, among other functions. Although carbohydrates (e.g. glucans, chitin) are the most abundant components, the fungal cell wall also harbors ionic proteins, proteins bound by disulfide bridges, alkali-extractable, SDS-extractable, and GPI-anchored proteins, among others; the latter consisting of suitable targets which can be used for fungal pathogen control. Pseudocercospora fijiensis is the causal agent of black Sigatoka disease, the principal threat to banana and plantain worldwide. Here, we report the isolation of the cell wall of this pathogen, followed by extensive washing to eliminate all loosely associated proteins and conserve those integrated to its cell wall. In the HF-pyridine protein fraction, one of the most abundant protein bands was recovered from SDS-PAGE gels, electro-eluted and sequenced. Seven proteins were identified from this band, none of which were GPI-anchored proteins. Instead, atypical (moonlight-like) cell wall proteins were identified, suggesting a new class of atypical proteins, bound to the cell wall by unknown linkages. Western blot and histological analyses of the cell wall fractions support that these proteins are true cell wall proteins, most likely involved in fungal pathogenesis/virulence, since they were found conserved in many fungal pathogens.
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Affiliation(s)
- Blondy Canto-Canché
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, Colonia Chuburná de Hidalgo, Calle 43 No. 130 x 32 y 34, Mérida, A.C., Yucatán, C.P. 97205, México
| | - Yamily Yazmin Burgos-Canul
- Unidad de Bioquímica y Biología Molecular de Plantas, Centro de Investigación Científica de Yucatán, Colonia Chuburná de Hidalgo, Calle 43 No. 130 x 32 y 34, Mérida, A.C., Yucatán, C.P. 97205, México
| | - Deysi Chi-Chuc
- Unidad de Bioquímica y Biología Molecular de Plantas, Centro de Investigación Científica de Yucatán, Colonia Chuburná de Hidalgo, Calle 43 No. 130 x 32 y 34, Mérida, A.C., Yucatán, C.P. 97205, México
- Escuela Telebachillerato Comunitario de Xcunya, Calle 20, Mérida, México
| | - Miguel Tzec-Simá
- Unidad de Bioquímica y Biología Molecular de Plantas, Centro de Investigación Científica de Yucatán, Colonia Chuburná de Hidalgo, Calle 43 No. 130 x 32 y 34, Mérida, A.C., Yucatán, C.P. 97205, México
| | - Angela Ku-González
- Unidad de Bioquímica y Biología Molecular de Plantas, Centro de Investigación Científica de Yucatán, Colonia Chuburná de Hidalgo, Calle 43 No. 130 x 32 y 34, Mérida, A.C., Yucatán, C.P. 97205, México
| | - Ligia Brito-Argáez
- Unidad de Bioquímica y Biología Molecular de Plantas, Centro de Investigación Científica de Yucatán, Colonia Chuburná de Hidalgo, Calle 43 No. 130 x 32 y 34, Mérida, A.C., Yucatán, C.P. 97205, México
| | - Mildred Carrillo-Pech
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, Colonia Chuburná de Hidalgo, Calle 43 No. 130 x 32 y 34, Mérida, A.C., Yucatán, C.P. 97205, México
| | - César De Los Santos-Briones
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, Colonia Chuburná de Hidalgo, Calle 43 No. 130 x 32 y 34, Mérida, A.C., Yucatán, C.P. 97205, México
| | - Miguel Ángel Canseco-Pérez
- Dirección de Investigación, Evaluación y Posgrado, Universidad Tecnológica de Tlaxcala, Carretera a el Carmen Xalplatlahuaya s/n. El Carmen Xalplatlahuaya, Tlaxcala, Huamantla, C.P. 90500, Mexico
| | - Donato Luna-Moreno
- Centro de Investigaciones en Óptica AC, División de Fotónica, Loma del Bosque 115, Col. Lomas del Campestre, León, Gto, C.P. 37150, México
| | | | - Ignacio Islas-Flores
- Unidad de Bioquímica y Biología Molecular de Plantas, Centro de Investigación Científica de Yucatán, Colonia Chuburná de Hidalgo, Calle 43 No. 130 x 32 y 34, Mérida, A.C., Yucatán, C.P. 97205, México.
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Cho GH, Bae HC, Cho WY, Jeong EM, Park HJ, Yang HR, Wang SY, Kim YJ, Shin DM, Chung HM, Kim IG, Han HS. High-glutathione mesenchymal stem cells isolated using the FreSHtracer probe enhance cartilage regeneration in a rabbit chondral defect model. Biomater Res 2023; 27:54. [PMID: 37259149 PMCID: PMC10233867 DOI: 10.1186/s40824-023-00398-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 05/20/2023] [Indexed: 06/02/2023] Open
Abstract
BACKGROUND Mesenchymal stem cells (MSCs) are a promising cell source for cartilage regeneration. However, the function of MSC can vary according to cell culture conditions, donor age, and heterogeneity of the MSC population, resulting in unregulated MSC quality control. To overcome these limitations, we previously developed a fluorescent real-time thiol tracer (FreSHtracer) that monitors cellular levels of glutathione (GSH), which are known to be closely associated with stem cell function. In this study, we investigated whether using FreSHtracer could selectively separate high-functioning MSCs based on GSH levels and evaluated the chondrogenic potential of MSCs with high GSH levels to repair cartilage defects in vivo. METHODS Flow cytometry was conducted on FreSHtracer-loaded MSCs to select cells according to their GSH levels. To determine the function of FreSHtracer-isolated MSCs, mRNA expression, migration, and CFU assays were conducted. The MSCs underwent chondrogenic differentiation, followed by analysis of chondrogenic-related gene expression. For in vivo assessment, MSCs with different cellular GSH levels or cell culture densities were injected in a rabbit chondral defect model, followed by histological analysis of cartilage-regenerated defect sites. RESULTS FreSHtracer successfully isolated MSCs according to GSH levels. MSCs with high cellular GSH levels showed enhanced MSC function, including stem cell marker mRNA expression, migration, CFU, and oxidant resistance. Regardless of the stem cell tissue source, FreSHtracer selectively isolated MSCs with high GSH levels and high functionality. The in vitro chondrogenic potential was the highest in pellets generated by MSCs with high GSH levels, with increased ECM formation and chondrogenic marker expression. Furthermore, the MSCs' function was dependent on cell culture conditions, with relatively higher cell culture densities resulting in higher GSH levels. In vivo, improved cartilage repair was achieved by articular injection of MSCs with high levels of cellular GSH and MSCs cultured under high-density conditions, as confirmed by Collagen type 2 IHC, Safranin-O staining and O'Driscoll scores showing that more hyaline cartilage was formed on the defects. CONCLUSION FreSHtracer selectively isolates highly functional MSCs that have enhanced in vitro chondrogenesis and in vivo hyaline cartilage regeneration, which can ultimately overcome the current limitations of MSC therapy.
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Affiliation(s)
- Gun Hee Cho
- Department of Orthopedic Surgery, College of Medicine, Seoul National University, 101 Daehak-Ro, Jongno-Gu, Seoul, 03080, Republic of Korea
- Department of Orthopedic Surgery, Seoul National University Hospital, Yongondong Chongnogu, Seoul, 110-744, Republic of Korea
| | - Hyun Cheol Bae
- Department of Orthopedic Surgery, Seoul National University Hospital, Yongondong Chongnogu, Seoul, 110-744, Republic of Korea
| | - Won Young Cho
- Department of Orthopedic Surgery, Seoul National University Hospital, Yongondong Chongnogu, Seoul, 110-744, Republic of Korea
| | - Eui Man Jeong
- Department of Pharmacy, College of Pharmacy, Jeju National University, Jeju Special Self-Governing Province, Jeju-do, Republic of Korea
| | - Hee Jung Park
- Department of Orthopedic Surgery, Seoul National University Hospital, Yongondong Chongnogu, Seoul, 110-744, Republic of Korea
| | - Ha Ru Yang
- Department of Orthopedic Surgery, Seoul National University Hospital, Yongondong Chongnogu, Seoul, 110-744, Republic of Korea
| | - Sun Young Wang
- Department of Orthopedic Surgery, Seoul National University Hospital, Yongondong Chongnogu, Seoul, 110-744, Republic of Korea
| | - You Jung Kim
- Department of Orthopedic Surgery, Seoul National University Hospital, Yongondong Chongnogu, Seoul, 110-744, Republic of Korea
| | - Dong Myung Shin
- Department of Biomedical Sciences, Asan Medical Center, University of Ulsan College of Medicine, 88 Olymic-Ro 43-Gil, Songpa-Gu, Seoul, 05505, Republic of Korea
| | - Hyung Min Chung
- Department of Stem Cell Biology, School of Medicine, Konkuk University, Seoul, 05029, Republic of Korea
| | - In Gyu Kim
- Laboratory for Cellular Response to Oxidative Stress, Cell2in, Inc, Seoul, 03127, Republic of Korea
| | - Hyuk-Soo Han
- Department of Orthopedic Surgery, College of Medicine, Seoul National University, 101 Daehak-Ro, Jongno-Gu, Seoul, 03080, Republic of Korea.
- Department of Orthopedic Surgery, Seoul National University Hospital, Yongondong Chongnogu, Seoul, 110-744, Republic of Korea.
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6
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Wu P, Choo CYL, Lu H, Wei X, Chen Y, Yago JI, Chung K. Pexophagy is critical for fungal development, stress response, and virulence in Alternaria alternata. MOLECULAR PLANT PATHOLOGY 2022; 23:1538-1554. [PMID: 35810316 PMCID: PMC9452759 DOI: 10.1111/mpp.13247] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 06/16/2022] [Accepted: 06/22/2022] [Indexed: 06/09/2023]
Abstract
Alternaria alternata can resist high levels of reactive oxygen species (ROS). The protective roles of autophagy or autophagy-mediated degradation of peroxisomes (termed pexophagy) against oxidative stress remain unclear. The present study, using transmission electron microscopy and fluorescence microscopy coupled with a GFP-AaAtg8 proteolysis assay and an mCherry tagging assay with peroxisomal targeting tripeptides, demonstrated that hydrogen peroxide (H2 O2 ) and nitrogen depletion induced autophagy and pexophagy. Experimental evidence showed that H2 O2 triggered autophagy and the translocation of peroxisomes into the vacuoles. Mutational inactivation of the AaAtg8 gene in A. alternata led to autophagy impairment, resulting in the accumulation of peroxisomes, increased ROS sensitivity, and decreased virulence. Compared to the wild type, ΔAaAtg8 failed to detoxify ROS effectively, leading to ROS accumulation. Deleting AaAtg8 down-regulated the expression of genes encoding an NADPH oxidase and a Yap1 transcription factor, both involved in ROS resistance. Deleting AaAtg8 affected the development of conidia and appressorium-like structures. Deleting AaAtg8 also compromised the integrity of the cell wall. Reintroduction of a functional copy of AaAtg8 in the mutant completely restored all defective phenotypes. Although ΔAaAtg8 produced wild-type toxin levels in axenic culture, the mutant induced a lower level of H2 O2 and smaller necrotic lesions on citrus leaves. In addition to H2 O2 , nitrogen starvation triggered peroxisome turnover. We concluded that ΔAaAtg8 failed to degrade peroxisomes effectively, leading to the accumulation of peroxisomes and the reduction of the stress response. Autophagy-mediated peroxisome turnover could increase cell adaptability and survival under oxidative stress and starvation conditions.
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Affiliation(s)
- Pei‐Ching Wu
- Department of Plant Pathology, College of Agriculture and Natural ResourcesNational Chung Hsing UniversityTaichungTaiwan
| | - Celine Yen Ling Choo
- Department of Plant Pathology, College of Agriculture and Natural ResourcesNational Chung Hsing UniversityTaichungTaiwan
| | - Hsin‐Yu Lu
- Department of Plant Pathology, College of Agriculture and Natural ResourcesNational Chung Hsing UniversityTaichungTaiwan
| | - Xian‐Yong Wei
- Department of Plant Pathology, College of Agriculture and Natural ResourcesNational Chung Hsing UniversityTaichungTaiwan
| | - Yu‐Kun Chen
- Department of Plant Pathology, College of Agriculture and Natural ResourcesNational Chung Hsing UniversityTaichungTaiwan
| | - Jonar I. Yago
- Plant Science Department, College of AgricultureNueva Vizcaya State UniversityBayombongPhilippines
| | - Kuang‐Ren Chung
- Department of Plant Pathology, College of Agriculture and Natural ResourcesNational Chung Hsing UniversityTaichungTaiwan
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7
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Luo X, Wang H, Wang M. Genomic Sequence Data of Alternaria alternata hznu325 Causing Black Leaf Spot on Chrysanthemum morifolium. PLANT DISEASE 2022; 106:2506-2510. [PMID: 35895327 DOI: 10.1094/pdis-11-21-2517-a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Affiliation(s)
- Xiujun Luo
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China
- Zhejiang Provincial Key Laboratory for Genetic Improvement and Quality Control of Medicinal Plants, Hangzhou Normal University, Hangzhou, 310036, China
| | - Huizhong Wang
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China
- Zhejiang Provincial Key Laboratory for Genetic Improvement and Quality Control of Medicinal Plants, Hangzhou Normal University, Hangzhou, 310036, China
| | - Mingshuang Wang
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China
- Zhejiang Provincial Key Laboratory for Genetic Improvement and Quality Control of Medicinal Plants, Hangzhou Normal University, Hangzhou, 310036, China
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8
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Yang Q, Yang J, Wang Y, Du J, Zhang J, Luisi BF, Liang W. Broad-spectrum chemicals block ROS detoxification to prevent plant fungal invasion. Curr Biol 2022; 32:3886-3897.e6. [PMID: 35932761 PMCID: PMC7613639 DOI: 10.1016/j.cub.2022.07.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 06/16/2022] [Accepted: 07/12/2022] [Indexed: 12/02/2022]
Abstract
Plant diseases cause a huge impact on food security and are of global concern. While application of agrochemicals is a common approach in the control of plant diseases currently, growing drug resistance and the impact of off-target effects of these compounds pose major challenges. The identification of pathogenicity-related virulence mechanisms and development of new chemicals that target these processes are urgently needed. One such virulence mechanism is the detoxification of reactive oxygen species (ROS) generated by host plants upon attack by pathogens. The machinery of ROS detoxification might therefore serve as a drug target for preventing plant diseases, but few anti-ROS-scavenging drugs have been developed. Here, we show that in the model system Botrytis cinerea secretion of the cytochrome c-peroxidase, BcCcp1 removes plant-produced H2O2 and promotes pathogen invasion. The peroxidase secretion is modulated by a Tom1-like protein, BcTol1, through physical interaction. We show that BcTol1 is regulated at different levels to enhance the secretion of BcCcp1 during the early infection stage. Inactivation of either BcTol1 or BcCcp1 leads to dramatically reduced virulence of B. cinerea. We identify two BcTol1-targeting small molecules that not only prevent B. cinerea invasion but also have effective activity against a wide range of plant fungal pathogens without detectable effect on the hosts. These findings reveal a conserved mechanism of ROS detoxification in fungi and provide a class of potential fungicides to control diverse plant diseases. The approach described here has wide implications for further drug discovery in related fields.
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Affiliation(s)
- Qianqian Yang
- College of Plant Health and Medicine, Engineering Research Center for Precision Pest Management for Fruits and Vegetables of Qingdao, Shandong Engineering Research Center for Environment-Friendly Agricultural Pest Management, Shandong Province Key Laboratory of Applied Mycology, Qingdao Agricultural University, Qingdao 266109, China
| | - Jinguang Yang
- Tobacco Research Institute of CAAS, Qingdao 266100, China
| | - Yameng Wang
- College of Plant Health and Medicine, Engineering Research Center for Precision Pest Management for Fruits and Vegetables of Qingdao, Shandong Engineering Research Center for Environment-Friendly Agricultural Pest Management, Shandong Province Key Laboratory of Applied Mycology, Qingdao Agricultural University, Qingdao 266109, China
| | - Juan Du
- College of Life Sciences, Qingdao Agricultural University, Qingdao 266109, China
| | - Jianan Zhang
- College of Plant Health and Medicine, Engineering Research Center for Precision Pest Management for Fruits and Vegetables of Qingdao, Shandong Engineering Research Center for Environment-Friendly Agricultural Pest Management, Shandong Province Key Laboratory of Applied Mycology, Qingdao Agricultural University, Qingdao 266109, China
| | - Ben F Luisi
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UK
| | - Wenxing Liang
- College of Plant Health and Medicine, Engineering Research Center for Precision Pest Management for Fruits and Vegetables of Qingdao, Shandong Engineering Research Center for Environment-Friendly Agricultural Pest Management, Shandong Province Key Laboratory of Applied Mycology, Qingdao Agricultural University, Qingdao 266109, China.
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9
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Luo X, Zhan X, Ruan R, Xi Y, Shen C, Wang H, Wang M. Genome-wide identification of the Penicillium digitatum bZIP gene family and the roles of one key member, PdatfA. Res Microbiol 2022; 173:103970. [PMID: 35868518 DOI: 10.1016/j.resmic.2022.103970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 07/03/2022] [Accepted: 07/08/2022] [Indexed: 11/16/2022]
Abstract
Penicillium digitatum is the most common cause of postharvest decay in citrus fruits around the world. Previous studies revealed that the bZIP gene family plays crucial roles in development, stress adaptation, and pathogenicity in fungi. However, little is known about the bZIP genes in P. digitatum. In this study, we systematically identified the bZIP family in 23 Penicillium species and analyzed their evolutionary relationships. We found that gene loss and gene duplication shaped the evolution of the Penicillium bZIP family. P. digitatum experienced 3 bZIP gene loss events, but with no gene duplication. We subsequently characterized the biological functions of one important member, PdatfA in P. digitatum by constructing the deletion mutant. Results showed that ΔPdatfA exhibited a moderate growth defect, reduced pigmentation, and slightly increased resistance to fungicides iprodione and fludioxonil. However, ΔPdatfA displayed similar rot symptoms to that of the wild type. The ΔPdatfA mycelia were not affected in response to oxidative stress while its conidia showed enhanced resistance due to the upregulation of catalases. Our results provide new insights into the evolution and functions of the bZIP gene family in Penicillium.
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Affiliation(s)
- Xiujun Luo
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China
| | - Xiaori Zhan
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China
| | - Ruoxin Ruan
- Hangzhou Academy of Agricultural Sciences, Hangzhou 310024, China
| | - Yue Xi
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China
| | - Chenjia Shen
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China
| | - Huizhong Wang
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China
| | - Mingshuang Wang
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China.
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10
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Lu HY, Huang YL, Wu PC, Wei XY, Yago JI, Chung KR. A zinc finger suppressor involved in stress resistance, cell wall integrity, conidiogenesis, and autophagy in the necrotrophic fungal pathogen Alternaria alternata. Microbiol Res 2022; 263:127106. [PMID: 35839700 DOI: 10.1016/j.micres.2022.127106] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 05/18/2022] [Accepted: 06/22/2022] [Indexed: 10/17/2022]
Abstract
The tangerine pathotype of Alternaria alternata can withstand high-level reactive oxygen species (ROS). By analyzing loss- and gain-of-function mutants, this study demonstrated that a Cys2His2 zinc finger-containing transcription regulator, A. alternata Stress Response Regulator 1 (AaSRR1), plays a negative role in resistance to peroxides and singlet-oxygen-generating compounds. AaSRR1 plays no role in cellular susceptibility or resistance to superoxide-producing compounds. AaSRR1 also negatively regulates conidiogenesis, maintenance of cell wall and membrane integrities, and chitin biosynthesis. Some wild-type hyphae displayed necrosis after exposure to 30 mM H2O2, whereas AaSRR1 deficient mutant (ΔAaSRR1) hyphae had visible granules and vacuoles. sGFP-AaATG8 proteolysis assays revealed that H2O2 and starvation could trigger autophagy formation in both wild type and ΔAaSRR1. Autophagy occurred at higher rates in ΔAaSRR1 than wild type under both conditions, particularly after H2O2 treatments, indicating that autophagy might contribute to ROS resistance. Upon exposure to H2O2 or under starvation, AaSRR1 was translocated into the nucleus, even though the expression of AaSRR1 was decreased. AaSRR1 is required for vegetative growth but is dispensable for fungal virulence as assayed on detached calamondin leaves. AaSRR1 suppressed the expression of the gene encoding a HOG1 mitogen-activated protein (MAP) kinase implicated in ROS resistance. Mutation of AaSRR1 increased catalase activity but decreased superoxide dismutase activity, leading to fewer ROS accumulation in the cytosol. Nevertheless, our results indicated that AaSRR1 is a transcription suppressor for ROS resistance. This study also revealed tradeoffs between stress responses and hyphal growth in A. alternata.
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Affiliation(s)
- Hsin-Yu Lu
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung Hsing University, Taichung 40227, Taiwan
| | - Yu-Ling Huang
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung Hsing University, Taichung 40227, Taiwan
| | - Pei-Ching Wu
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung Hsing University, Taichung 40227, Taiwan.
| | - Xian-Yong Wei
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung Hsing University, Taichung 40227, Taiwan
| | - Jonar I Yago
- Plant Science Department, College of Agriculture, Nueva Vizcaya State University, Bayombong, Nueva Vizcaya 3700, Philippines
| | - Kuang-Ren Chung
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung Hsing University, Taichung 40227, Taiwan.
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Impact of the antifungal protein PgAFP on the proteome and patulin production of Penicillium expansum on apple-based medium. Int J Food Microbiol 2021; 363:109511. [PMID: 34990884 DOI: 10.1016/j.ijfoodmicro.2021.109511] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 11/29/2021] [Accepted: 12/19/2021] [Indexed: 11/20/2022]
Abstract
Apples are prone to be contaminated with Penicillium expansum, which produces the mycotoxin patulin, posing a risk for human health. Antifungal treatments are required to control this fungal pathogen, although consumers demand products free of synthetic additives. Then, the use of antifungal proteins produced by moulds represents a novel and promising strategy. Although its inhibitory effect on P. expansum has been reported, the impact of these proteins on patulin production has been scarcely studied, pointing to a possible patulin overproduction. The aim of this work was to evaluate the effect of the antifungal protein PgAFP on the proteome and patulin biosynthesis of P. expansum grown in apple-based agar, intending to decipher these effects without the apple in vivo physiological response to the fungal infection. PgAFP increased the production of patulin on three of the five P. expansum strains evaluated. The proteome of the PgAFP-treated P. expansum showed five proteins involved in patulin biosynthesis in higher abundance (fold change 2.8-9.8), as well as proteins related to pathogenicity and virulence that suggest lower ability to infect fruits. Additionally, several proteins associated with oxidative stress, such as glutathione peroxidase, redoxin, or heat shock proteins were found in higher abundance, pointing to a response against oxidative stress elicited by PgAFP. These results provide evidence to be cautious in applying this antifungal protein in apples, being of utmost relevance to provide knowledge about the global response of P. expansum against an antifungal protein with many shared characteristics with others. These findings significantly contribute to future studies of assessment and suitability of not only these antifungal proteins but also new antifungal compounds.
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12
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Ma H, Li L, Gai Y, Zhang X, Chen Y, Zhuo X, Cao Y, Jiao C, Gmitter FG, Li H. Histone Acetyltransferases and Deacetylases Are Required for Virulence, Conidiation, DNA Damage Repair, and Multiple Stresses Resistance of Alternaria alternata. Front Microbiol 2021; 12:783633. [PMID: 34880849 PMCID: PMC8645686 DOI: 10.3389/fmicb.2021.783633] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Accepted: 11/02/2021] [Indexed: 01/16/2023] Open
Abstract
Histone acetylation, which is critical for transcriptional regulation and various biological processes in eukaryotes, is a reversible dynamic process regulated by HATs and HDACs. This study determined the function of 6 histone acetyltransferases (HATs) (Gcn5, RTT109, Elp3, Sas3, Sas2, Nat3) and 6 histone deacetylases (HDACs) (Hos2, Rpd3, Hda1, Hos3, Hst2, Sir2) in the phytopathogenic fungus Alternaria alternata by analyzing targeted gene deletion mutants. Our data provide evidence that HATs and HDACs are both required for mycelium growth, cell development and pathogenicity as many gene deletion mutants (ΔGcn5, ΔRTT109, ΔElp3, ΔSas3, ΔNat3, ΔHos2, and ΔRpd3) displayed reduced growth, conidiation or virulence at varying degrees. In addition, HATs and HDACs are involved in the resistance to multiple stresses such as oxidative stress (Sas3, Gcn5, Elp3, RTT109, Hos2), osmotic stress (Sas3, Gcn5, RTT109, Hos2), cell wall-targeting agents (Sas3, Gcn5, Hos2), and fungicide (Gcn5, Hos2). ΔGcn5, ΔSas3, and ΔHos2 displayed severe growth defects on sole carbon source medium suggesting a vital role of HATs and HDACs in carbon source utilization. More SNPs were generated in ΔGcn5 in comparison to wild-type when they were exposed to ultraviolet ray. Moreover, ΔRTT109, ΔGcn5, and ΔHos2 showed severe defects in resistance to DNA-damaging agents, indicating the critical role of HATs and HDACs in DNA damage repair. These phenotypes correlated well with the differentially expressed genes in ΔGcn5 and ΔHos2 that are essential for carbon sources metabolism, DNA damage repair, ROS detoxification, and asexual development. Furthermore, Gcn5 is required for the acetylation of H3K4. Overall, our study provides genetic evidence to define the central role of HATs and HDACs in the pathological and biological functions of A. alternata.
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Affiliation(s)
- Haijie Ma
- Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, College of Horticulture Science, Zhejiang A&F University, Hangzhou, China.,Key Lab of Molecular Biology of Crop Pathogens and Insects, Ministry of Agriculture, Institute of Biotechnology, Zhejiang University, Hangzhou, China.,Citrus Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, FL, United States
| | - Lei Li
- Key Lab of Molecular Biology of Crop Pathogens and Insects, Ministry of Agriculture, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Yunpeng Gai
- Key Lab of Molecular Biology of Crop Pathogens and Insects, Ministry of Agriculture, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Xiaoyan Zhang
- Key Lab of Molecular Biology of Crop Pathogens and Insects, Ministry of Agriculture, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Yanan Chen
- Key Lab of Molecular Biology of Crop Pathogens and Insects, Ministry of Agriculture, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Xiaokang Zhuo
- Citrus Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, FL, United States
| | - Yingzi Cao
- Key Lab of Molecular Biology of Crop Pathogens and Insects, Ministry of Agriculture, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Chen Jiao
- Key Lab of Molecular Biology of Crop Pathogens and Insects, Ministry of Agriculture, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Fred G Gmitter
- Citrus Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, FL, United States
| | - Hongye Li
- Key Lab of Molecular Biology of Crop Pathogens and Insects, Ministry of Agriculture, Institute of Biotechnology, Zhejiang University, Hangzhou, China
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Zhang H, Shen W, Zhang D, Shen X, Wang F, Hsiang T, Liu J, Li G. The bZIP Transcription Factor LtAP1 Modulates Oxidative Stress Tolerance and Virulence in the Peach Gummosis Fungus Lasiodiplodia theobromae. Front Microbiol 2021; 12:741842. [PMID: 34630367 PMCID: PMC8495313 DOI: 10.3389/fmicb.2021.741842] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 08/25/2021] [Indexed: 12/02/2022] Open
Abstract
Lasiodiplodia theobromae is one of the primary causal agents in peach gummosis disease, leading to enormous losses in peach production. In our previous study, a redox-related gene, LtAP1, from the fungus was significantly upregulated in peach shoots throughout infection. Here, we characterized LtAP1, a basic leucine zipper transcription factor, during peach gummosis progression using the CRISPR-Cas9 system and homologous recombination. The results showed that LtAP1-deletion mutant had slower vegetative growth and increased sensitivity to several oxidative and nitrosative stress agents. LtAP1 was highly induced by exogenous oxidants treatment in the L. theobromae wild-type strain. In a pathogenicity test, the deletion mutant showed decreased virulence (reduced size of necrotic lesions, less gum release, and decreased pathogen biomass) on infected peach shoots compared to the wild-type strain. The mutant showed severely reduced transcription levels of genes related to glutaredoxin and thioredoxin in L. theobroame under oxidative stress or during infection, indicating an attenuated capacity for reactive oxygen species (ROS) detoxification. When shoots were treated with an NADPH oxidase inhibitor, the pathogenicity of the mutant was partially restored. Moreover, ROS production and plant defense response were strongly activated in peach shoots infected by the mutant. These results highlight the crucial role of LtAP1 in the oxidative stress response, and further that it acts as an important virulence factor through modulating the fungal ROS-detoxification system and the plant defense response.
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Affiliation(s)
- He Zhang
- Key Laboratory of Horticultural Plant Biology-Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China.,Haikou Experimental Station, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
| | - Wanqi Shen
- Key Laboratory of Horticultural Plant Biology-Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Dongmei Zhang
- Key Laboratory of Horticultural Plant Biology-Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Xingyi Shen
- Key Laboratory of Horticultural Plant Biology-Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Fan Wang
- Jiangxi Oil-tea Camellia, Jiujiang University, Jiujiang, China
| | - Tom Hsiang
- School of Environmental Sciences, University of Guelph, Guelph, ON, Canada
| | - Junwei Liu
- Key Laboratory of Horticultural Plant Biology-Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Guohuai Li
- Key Laboratory of Horticultural Plant Biology-Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China
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14
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Zhang X, Zong Y, Gong D, Yu L, Sionov E, Bi Y, Prusky D. NADPH Oxidase Regulates the Growth and Pathogenicity of Penicillium expansum. FRONTIERS IN PLANT SCIENCE 2021; 12:696210. [PMID: 34456938 PMCID: PMC8387719 DOI: 10.3389/fpls.2021.696210] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 07/19/2021] [Indexed: 05/31/2023]
Abstract
The occurrence of reactive oxygen species (ROS) during the colonization of necrotrophic pathogens attacking fruit is critical during the attack, but its importance in Penicillium expansum remains unclear. This study aimed to determine the regulatory effects of NADPH oxidase (Nox) genes on the growth and pathogenicity of P. expansum in apple fruits. Deletion mutants of ΔPeNoxA, ΔPeNoxR, and ΔPeRacA genes were constructed to determine the contribution to the colonization process. The ΔPeRacA strain had a significant effect on the reduction of growth and pathogenicity, the ΔPeNoxA strain negatively regulated the growth and development of P. expansum and did not show any significant effect on the pathogenicity, and the ΔPeNoxR strain showed no effect on the growth or pathogenicity of P. expansum in the apple fruits. However, analysis of the content of O2 - and H2O2 in the mycelium of all the Nox mutants showed a significant reduction, confirming the functionality of Nox mutations. Growth under stress conditions in the presence of Congo red, sodium lauryl sulfate, and H2O2 showed a negative effect on the radial growth of ΔPeNoxA, but a positive effect on radial growth reduction by ΔPeNoxR and ΔPeRacA mutants was shown. Interestingly, the host antioxidant activity levels of superoxide dismutase (SOD) andcatalase (CAT) in the fruits after inoculation with ΔPeNoxA, ΔPeNoxR, and ΔPeRacA mutants declined, suggesting reduced ROS accumulation in the colonized region. These results suggest that PeNoxA, PeNoxR, and PeRacA differentially regulate the growth and pathogenicity of P. expansum by producing ROS, and that PeRacA showed the strongest regulatory effect.
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Affiliation(s)
- Xuemei Zhang
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, China
| | - Yuanyuan Zong
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, China
| | - Di Gong
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, China
| | - Lirong Yu
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, China
| | - Edward Sionov
- Department of Postharvest Science of Fresh Produce, Agricultural Research Organization, Volcani Center, Rishon LeZion, Israel
| | - Yang Bi
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, China
| | - Dov Prusky
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, China
- Department of Postharvest Science of Fresh Produce, Agricultural Research Organization, Volcani Center, Rishon LeZion, Israel
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15
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Wu PC, Chen YK, Yago JI, Chung KR. Peroxisomes Implicated in the Biosynthesis of Siderophores and Biotin, Cell Wall Integrity, Autophagy, and Response to Hydrogen Peroxide in the Citrus Pathogenic Fungus Alternaria alternata. Front Microbiol 2021; 12:645792. [PMID: 34262533 PMCID: PMC8273606 DOI: 10.3389/fmicb.2021.645792] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 05/25/2021] [Indexed: 11/13/2022] Open
Abstract
Little is known about the roles of peroxisomes in the necrotrophic fungal plant pathogens. In the present study, a Pex6 gene encoding an ATPase-associated protein was characterized by analysis of functional mutations in the tangerine pathotype of Alternaria alternata, which produces a host-selective toxin. Peroxisomes were observed in fungal cells by expressing a mCherry fluorescent protein tagging with conserved tripeptides serine-lysing-leucine and transmission electron microscopy. The results indicated that Pex6 plays no roles in peroxisomal biogenesis but impacts protein import into peroxisomes. The number of peroxisomes was affected by nutritional conditions and H2O2, and their degradation was mediated by an autophagy-related machinery termed pexophagy. Pex6 was shown to be required for the formation of Woronin bodies, the biosynthesis of biotin, siderophores, and toxin, the uptake and accumulation of H2O2, growth, and virulence, as well as the Slt2 MAP kinase-mediated maintenance of cell wall integrity. Adding biotin, oleate, and iron in combination fully restored the growth of the pex6-deficient mutant (Δpex6), but failed to restore Δpex6 virulence to citrus. Adding purified toxin could only partially restore Δpex6 virulence even in the presence of biotin, oleate, and iron. Sensitivity assays revealed that Pex6 plays no roles in resistance to H2O2 and superoxide, but plays a negative role in resistance to 2-chloro-5-hydroxypyridine (a hydroxyl radical-generating compound), eosin Y and rose Bengal (singlet oxygen-generating compounds), and 2,3,5-triiodobenzoic acid (an auxin transport inhibitor). The diverse functions of Pex6 underscore the importance of peroxisomes in physiology, pathogenesis, and development in A. alternata.
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Affiliation(s)
- Pei-Ching Wu
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung Hsing University, Taichung, Taiwan
| | - Yu-Kun Chen
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung Hsing University, Taichung, Taiwan
| | - Jonar I. Yago
- Plant Science Department, College of Agriculture, Nueva Vizcaya State University, Bayombong, Philippines
| | - Kuang-Ren Chung
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung Hsing University, Taichung, Taiwan
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16
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Huang Z, Lu J, Liu R, Wang P, Hu Y, Fang A, Yang Y, Qing L, Bi C, Yu Y. SsCat2 encodes a catalase that is critical for the antioxidant response, QoI fungicide sensitivity, and pathogenicity of Sclerotinia sclerotiorum. Fungal Genet Biol 2021; 149:103530. [PMID: 33561548 DOI: 10.1016/j.fgb.2021.103530] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/26/2021] [Accepted: 02/01/2021] [Indexed: 10/22/2022]
Abstract
Sclerotinia sclerotiorum is a destructive necrotrophic fungal pathogen with worldwide distribution. The metabolism of reactive oxygen species (ROS) is critical for the development and infection process of this economically important pathogen. Hydrogen peroxide (H2O2) is converted into water and dioxygen by catalases, which are major ROS scavengers in cells. Several genes have been predicted to encode the catalases of S. sclerotiorum, but the critical ones that function in the ROS stress response are still unknown. In this research, a catalase gene called SsCat2 was found to contribute to the predominant catalase activity at the stages of hyphae growth and sclerotial development. SsCat2 transcripts were induced under oxidative stress, and the target deletion of SsCat2 led to significant sensitivity to H2O2, suggesting that SsCat2 is critical in dealing with the oxidative stress. SsCat2-deletion strains were sensitive to hyperosmotic stresses and cell membrane-perturbing agents, suggesting impairment in cell integrity due to the inactivation of SsCat2. The expression of the alternative oxidase-encoding gene was upregulated in the SsCat2-deletion strains, which showed decreased sensitivity to QoI fungicides. SsCat2-deletion strains showed impaired virulence in different hosts, and more H2O2 accumulation was detected during the infect processes. In summary, these results indicate that SsCat2 encodes a catalase that is related to the oxidative stress response, QoI fungicide sensitivity, and pathogenicity of S. sclerotiorum.
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Affiliation(s)
- Zhiqiang Huang
- College of Plant Protection, Southwest University, Chongqing, China
| | - Jingjing Lu
- College of Plant Protection, Southwest University, Chongqing, China
| | - Ruiwen Liu
- College of Plant Protection, Southwest University, Chongqing, China
| | - Pei Wang
- College of Plant Protection, Southwest University, Chongqing, China
| | - Yawen Hu
- College of Plant Protection, Southwest University, Chongqing, China
| | - Anfei Fang
- College of Plant Protection, Southwest University, Chongqing, China
| | - Yuheng Yang
- College of Plant Protection, Southwest University, Chongqing, China
| | - Ling Qing
- College of Plant Protection, Southwest University, Chongqing, China
| | - Chaowei Bi
- College of Plant Protection, Southwest University, Chongqing, China
| | - Yang Yu
- College of Plant Protection, Southwest University, Chongqing, China; State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Chongqing, China.
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17
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Feng H, Xu M, Gao Y, Liang J, Guo F, Guo Y, Huang L. Vm-milR37 contributes to pathogenicity by regulating glutathione peroxidase gene VmGP in Valsa mali. MOLECULAR PLANT PATHOLOGY 2021; 22:243-254. [PMID: 33278058 PMCID: PMC7814965 DOI: 10.1111/mpp.13023] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 10/18/2020] [Accepted: 11/05/2020] [Indexed: 05/22/2023]
Abstract
MicroRNAs play important roles in various biological processes by regulating their corresponding target genes. However, the function and regulatory mechanism of fungal microRNA-like RNAs (milRNAs) are still largely unknown. In this study, a milRNA (Vm-milR37) was isolated and identified from Valsa mali, which causes the most serious disease on the trunk of apple trees in China. Based on the results of deep sequencing and quantitative reverse transcription PCR, Vm-milR37 was found to be expressed in the mycelium, while it was not expressed during the V. mali infection process. Overexpression of Vm-milR37 did not affect vegetative growth, but significantly decreased pathogenicity. Based on degradome sequencing, the target of Vm-milR37 was identified as VmGP, a glutathione peroxidase. The expression of Vm-milR37 and VmGP showed a divergent trend in V. mali-apple interaction samples and Vm-milR37 overexpression transformants. The expression of VmGP could be suppressed significantly by Vm-milR37 when coexpressed in tobacco leaves. Deletion of VmGP showed significantly reduced pathogenicity compared with the wild type. VmGP deletion mutants showed more sensitivity to hydrogen peroxide. Apple leaves inoculated with Vm-milR37 overexpression transformants and VmGP deletion mutant displayed increased accumulation of reactive oxygen species compared with the wild type. Thus, Vm-milR37 plays a critical role in pathogenicity by regulating VmGP, which contributes to the oxidative stress response during V. mali infection. These results provide important evidence to define the roles of milRNAs and their corresponding target genes in pathogenicity.
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Affiliation(s)
- Hao Feng
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant ProtectionNorthwest A&F UniversityYanglingChina
| | - Ming Xu
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant ProtectionNorthwest A&F UniversityYanglingChina
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life SciencesNorthwest A&F UniversityYanglingChina
| | - Yuqi Gao
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant ProtectionNorthwest A&F UniversityYanglingChina
| | - Jiahao Liang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant ProtectionNorthwest A&F UniversityYanglingChina
| | - Feiran Guo
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant ProtectionNorthwest A&F UniversityYanglingChina
| | - Yan Guo
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant ProtectionNorthwest A&F UniversityYanglingChina
| | - Lili Huang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant ProtectionNorthwest A&F UniversityYanglingChina
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18
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The critical role of MetR/ MetB/ MetC/ MetX in cysteine and methionine metabolism, fungal development and virulence of Alternaria alternata. Appl Environ Microbiol 2021; 87:AEM.01911-20. [PMID: 33277273 PMCID: PMC7851696 DOI: 10.1128/aem.01911-20] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Methionine is a unique sulfur-containing amino acid, which plays an important role in biological protein synthesis and various cellular processes. Here, we characterized the biological functions of AaMetB, AaMetC, and AaMetX in the tangerine pathotype of Alternaria alternata Morphological analysis showed that the mutants lacking AaMetB, AaMetC, or AaMetX resulted in less aerial hypha and fewer conidia in artificial media. Pathogenicity analysis showed that AaMetB, AaMetC, and AaMetX are required for full virulence. The defects in vegetative growth, conidiation and virulence of ΔMetB, ΔMetC, and ΔMetX can be restored by exogenous methionine and homocysteine, indicating that AaMetB, AaMetC, and AaMetX are required for methionine biosynthesis. However, exogenous cysteine only restored the growth and virulence defects of ΔMetR but not ΔMetB/C/X, suggesting that AaMetR is essential for cysteine biosynthesis. Oxidant sensitivity assay showed that only ΔMetR is sensitive to H2O2 and many ROS-generating compounds, indicating that AaMetR is essential for oxidative tolerance. Interestingly, fungicides indoor bioassays showed that only the ΔMetR mutants are susceptive to chlorothalonil, a fungicide that could bind to the cysteine of glyceraldehyde-3-phosphate dehydrogenase. Comparative transcriptome analysis showed that the inactivation of MetB, MetC, MetX, or MetR significantly affected the expression of methionine metabolism-related genes. Moreover, the inactivation of AaMetR significantly affected the expression of many genes related to glutathione metabolism, which is essential for ROS tolerance. Taken together, our study provides genetic evidence to define the critical roles of AaMetB, AaMetC, AaMetX, and AaMetR in cysteine and methionine metabolism, fungal development and virulence of Alternaria alternata IMPORTANCE The transcription factor METR regulating methionine metabolism is essential for reactive oxygen species (ROS) tolerance and virulence in many phytopathogenic fungi. However, the underlying regulatory mechanism of METR involved in this process is still unclear. In the present study, we generated AaMetB, AaMetC and AaMetX deletion mutants and compared these mutants with AaMetR disrupted mutants. Interestingly, we found that AaMetB, AaMetC and AaMetX are required for vegetative growth, conidiation, and pathogenicity in Alternaria alternata, but not for ROS tolerance and cysteine metabolism. Furthermore, we found that METR is involved in the biosynthesis of cysteine, which is an essential substrate for the biosynthesis of methionine and glutathione. This study emphasizes the critical roles of MetR, MetB, MetC, MetX in the regulation of cysteine and methionine metabolism, as well as the cross-link with glutathione-mediated ROS tolerance in phytopathogenic fungi, which provides a foundation for future investigations.
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19
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Riyazuddin R, Gupta R. Plausible Involvement of Ethylene in Plant Ferroptosis: Prospects and Leads. FRONTIERS IN PLANT SCIENCE 2021; 12:680709. [PMID: 34262583 PMCID: PMC8273338 DOI: 10.3389/fpls.2021.680709] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 05/31/2021] [Indexed: 05/03/2023]
Affiliation(s)
- Riyazuddin Riyazuddin
- Department of Plant Biology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
- Doctoral School in Biology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Ravi Gupta
- Department of Botany, School of Chemical and Life Sciences, Jamia Hamdard, New Delhi, India
- *Correspondence: Ravi Gupta ;
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20
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Zhang J, Hao H, Wu X, Wang Q, Chen M, Feng Z, Chen H. The functions of glutathione peroxidase in ROS homeostasis and fruiting body development in Hypsizygus marmoreus. Appl Microbiol Biotechnol 2020; 104:10555-10570. [PMID: 33175244 DOI: 10.1007/s00253-020-10981-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 10/15/2020] [Accepted: 10/26/2020] [Indexed: 12/28/2022]
Abstract
Glutathione peroxidase (GPX) is one of the most important antioxidant enzymes for maintaining reactive oxygen species (ROS) homeostasis. Although studies on fungi have suggested many important physiological functions of GPX, few studies have examined the role of this enzyme in Basidiomycetes, particularly its functions in fruiting body developmental processes. In the present study, GPX-silenced (GPxi) strains were obtained by using RNA interference. The GPxi strains of Hypsizygus marmoreus showed defects in mycelial growth and fruiting body development. In addition, the results indicated essential roles of GPX in controlling ROS homeostasis by regulating intracellular H2O2 levels, maintaining GSH/GSSG balance, and promoting antioxidant enzyme activity. Furthermore, lignocellulose enzyme activity levels were reduced and the mitochondrial phenotype and mitochondrial complex activity levels were changed in the H. marmoreus GPxi strains, possibly in response to impediments to mycelial growth and fruiting body development. These findings indicate that ROS homeostasis has a complex influence on growth, fruiting body development, GSH/GSSG balance, and carbon metabolism in H. marmoreus.Key points• ROS balance, energy metabolism, fruiting development.
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Affiliation(s)
- Jinjing Zhang
- National Research Center for Edible Fungi Biotechnology and Engineering, Key Laboratory of Applied Mycological Resources and Utilization, Ministry of Agriculture, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Institute of Edible Fungi, Shanghai Academy of Agricultural Sciences, 309 Room, No. 1000, Jinqi Road, Fengxian District, Shanghai, 201403, China
| | - Haibo Hao
- National Research Center for Edible Fungi Biotechnology and Engineering, Key Laboratory of Applied Mycological Resources and Utilization, Ministry of Agriculture, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Institute of Edible Fungi, Shanghai Academy of Agricultural Sciences, 309 Room, No. 1000, Jinqi Road, Fengxian District, Shanghai, 201403, China
| | - Xuelan Wu
- National Research Center for Edible Fungi Biotechnology and Engineering, Key Laboratory of Applied Mycological Resources and Utilization, Ministry of Agriculture, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Institute of Edible Fungi, Shanghai Academy of Agricultural Sciences, 309 Room, No. 1000, Jinqi Road, Fengxian District, Shanghai, 201403, China
| | - Qian Wang
- National Research Center for Edible Fungi Biotechnology and Engineering, Key Laboratory of Applied Mycological Resources and Utilization, Ministry of Agriculture, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Institute of Edible Fungi, Shanghai Academy of Agricultural Sciences, 309 Room, No. 1000, Jinqi Road, Fengxian District, Shanghai, 201403, China
| | - Mingjie Chen
- National Research Center for Edible Fungi Biotechnology and Engineering, Key Laboratory of Applied Mycological Resources and Utilization, Ministry of Agriculture, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Institute of Edible Fungi, Shanghai Academy of Agricultural Sciences, 309 Room, No. 1000, Jinqi Road, Fengxian District, Shanghai, 201403, China
| | - Zhiyong Feng
- National Research Center for Edible Fungi Biotechnology and Engineering, Key Laboratory of Applied Mycological Resources and Utilization, Ministry of Agriculture, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Institute of Edible Fungi, Shanghai Academy of Agricultural Sciences, 309 Room, No. 1000, Jinqi Road, Fengxian District, Shanghai, 201403, China.,College of Life Science, Nanjing Agricultural University, No. 1, Weigang road, XuanWu District, Nanjing, 210095, China
| | - Hui Chen
- National Research Center for Edible Fungi Biotechnology and Engineering, Key Laboratory of Applied Mycological Resources and Utilization, Ministry of Agriculture, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Institute of Edible Fungi, Shanghai Academy of Agricultural Sciences, 309 Room, No. 1000, Jinqi Road, Fengxian District, Shanghai, 201403, China.
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Wu PC, Chen CW, Choo CYL, Chen YK, Yago JI, Chung KR. Proper Functions of Peroxisomes Are Vital for Pathogenesis of Citrus Brown Spot Disease Caused by Alternaria alternata. J Fungi (Basel) 2020; 6:jof6040248. [PMID: 33114679 PMCID: PMC7712655 DOI: 10.3390/jof6040248] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 10/14/2020] [Accepted: 10/24/2020] [Indexed: 11/27/2022] Open
Abstract
In addition to the production of a host-selective toxin, the tangerine pathotype of Alternaria alternata must conquer toxic reactive oxygen species (ROS) in order to colonize host plants. The roles of a peroxin 6-coding gene (pex6) implicated in protein import into peroxisomes was functionally characterized to gain a better understanding of molecular mechanisms in ROS resistance and fungal pathogenicity. The peroxisome is a vital organelle involved in metabolisms of fatty acids and hydrogen peroxide in eukaryotes. Targeted deletion of pex6 had no impacts on the biogenesis of peroxisomes and cellular resistance to ROS. The pex6 deficient mutant (Δpex6) reduced toxin production by 40% compared to wild type and barely induce necrotic lesions on citrus leaves. Co-inoculation of purified toxin with Δpex6 conidia on citrus leaves, however, failed to fully restore lesion formation, indicating that toxin only partially contributed to the loss of Δpex6 pathogenicity. Δpex6 conidia germinated poorly and formed fewer appressorium-like structures (nonmelanized enlargement of hyphal tips) than wild type. Δpex6 hyphae grew slowly and failed to penetrate beyond the epidermal layers. Moreover, Δpex6 had thinner cell walls and lower viability. All of these defects resulting from deletion of pex6 could also account for the loss of Δpex6 pathogenicity. Overall, our results have demonstrated that proper peroxisome functions are of vital importance to pathogenesis of the tangerine pathotype of A. alternata.
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Affiliation(s)
- Pei-Ching Wu
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung Hsing University, Taichung 40227, Taiwan; (C.-W.C.); (C.Y.L.C.); (Y.-K.C.)
- Correspondence: (P.-C.W.); (K.-R.C.); Tel.: +886-4-22840780 (ext. 316) (P.-C.W.); +886-4-22840780 (ext. 301) (K.-R.C.)
| | - Chia-Wen Chen
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung Hsing University, Taichung 40227, Taiwan; (C.-W.C.); (C.Y.L.C.); (Y.-K.C.)
| | - Celine Yen Ling Choo
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung Hsing University, Taichung 40227, Taiwan; (C.-W.C.); (C.Y.L.C.); (Y.-K.C.)
| | - Yu-Kun Chen
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung Hsing University, Taichung 40227, Taiwan; (C.-W.C.); (C.Y.L.C.); (Y.-K.C.)
| | - Jonar I. Yago
- Plant Science Department, College of Agriculture, Nueva Vizcaya State University, Bayombong, Nueva Vizcaya 3700, Philippines;
| | - Kuang-Ren Chung
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung Hsing University, Taichung 40227, Taiwan; (C.-W.C.); (C.Y.L.C.); (Y.-K.C.)
- Correspondence: (P.-C.W.); (K.-R.C.); Tel.: +886-4-22840780 (ext. 316) (P.-C.W.); +886-4-22840780 (ext. 301) (K.-R.C.)
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Zhang H, Zhang D, Wang F, Hsiang T, Liu J, Li G. Lasiodiplodia theobromae-induced alteration in ROS metabolism and its relation to gummosis development in Prunus persica. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2020; 154:43-53. [PMID: 32526610 DOI: 10.1016/j.plaphy.2020.05.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 05/18/2020] [Accepted: 05/19/2020] [Indexed: 05/21/2023]
Abstract
Peach gummosis caused by Lasiodiplodia theobromae is one of the most detrimental diseases to peaches in southern China. Reactive oxygen species (ROS) play major roles in plant-pathogen interactions, however, their roles in the pathogenesis of peach gummosis, especially shoot disease in perennials, are largely unknown. In this study, the effects of L. theobromae on ROS production-scavenging systems and on signalling transduction during L. theobromae-induced gummosis in current-year peach shoots were investigated. The infection by L. theobromae led to a ROS burst and activated the plant antioxidant enzyme-dependent scavenging system. With disease progression, the capacity of the plant antioxidant machinery declined, and allowed for ROS accumulation and eventual malondialdehyde production. As for the fungus L. theobromae, the transcripts of genes related to ROS production were significantly repressed, and concomitantly the expression of genes related to antioxidant systems and oxidative stress resistance was markedly upregulated, perhaps to alleviate oxidative stress for successful colonisation. Moreover, genes involved in phytohormones biosynthesis and pathogenesis-related proteins were all markedly promoted, which could contribute to the restriction of disease development in peach shoots. Overall, the results showed that the ROS production-scavenging system in P. persica might affect disease development during peach-L. theobromae interaction. Our findings lay the foundations for future in-depth investigations of the molecular mechanisms and regulatory networks underlying L. theobromae-mediated shoot diseases in terms of ROS production-scavenging systems.
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Affiliation(s)
- He Zhang
- Key Laboratory of Horticultural Plant Biology-Ministry of Education, College of Horticulture and Forest Sciences, Huazhong Agricultural University, Wuhan, 430070, Hubei Province, China
| | - Dongmei Zhang
- Key Laboratory of Horticultural Plant Biology-Ministry of Education, College of Horticulture and Forest Sciences, Huazhong Agricultural University, Wuhan, 430070, Hubei Province, China
| | - Fan Wang
- College of Pharmacy and Life Science, Jiujiang University, Jiujiang, 332005, Jiangxi Province, China
| | - Tom Hsiang
- School of Environmental Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Junwei Liu
- Key Laboratory of Horticultural Plant Biology-Ministry of Education, College of Horticulture and Forest Sciences, Huazhong Agricultural University, Wuhan, 430070, Hubei Province, China.
| | - Guohuai Li
- Key Laboratory of Horticultural Plant Biology-Ministry of Education, College of Horticulture and Forest Sciences, Huazhong Agricultural University, Wuhan, 430070, Hubei Province, China.
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The siderophore repressor SreA maintains growth, hydrogen peroxide resistance, and cell wall integrity in the phytopathogenic fungus Alternaria alternata. Fungal Genet Biol 2020; 139:103384. [PMID: 32278718 DOI: 10.1016/j.fgb.2020.103384] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 03/25/2020] [Accepted: 03/31/2020] [Indexed: 01/18/2023]
Abstract
The siderophore-mediated iron uptake machinery is required by the tangerine pathotype of Alternaria alternata to colonize host plants. The present study reports the functions of the GATA-type transcription regulator SreA by analyzing loss- and gain-of-function mutants. The expression of sreA is transiently upregulated by excess iron. The sreA deficiency mutant (ΔsreA) shows severe growth defect but produces ACT toxin and incites necrotic lesions on citrus leaves as efficiently as wild type. SreA suppresses the expression of genes encoding polypeptides required for siderophore biosynthesis and transport under iron-replete conditions. Under iron-replete conditions, SreA impacts the expression of the genes encoding the NADPH oxidase complex involved in H2O2 production. SreA negatively impacts H2O2 resistance as ΔsreA increases resistance to H2O2. However, sreA deficiency has no effects on the expression of genes encoding several key factors (Yap1, Hog1, and Skn7) involved in oxidative stress resistance. ΔsreA increases resistance to calcofluor white and Congo red, which may suggest a role of SreA in the maintenance of cell wall integrity. Those are novel phenotypes associated with fungal sreA. Overall, our results indicate that SreA is required to protect fungal cells from cytotoxicity caused by excess iron. The results also highlight the regulatory functions of SreA and provide insights into the critical role of siderophore-mediated iron homeostasis in resistance to oxidative stress in A. alternata.
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Wang PH, Wu PC, Huang R, Chung KR. The Role of a Nascent Polypeptide-Associated Complex Subunit Alpha in Siderophore Biosynthesis, Oxidative Stress Response, and Virulence in Alternaria alternata. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2020; 33:668-679. [PMID: 31928525 DOI: 10.1094/mpmi-11-19-0315-r] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The present study demonstrates that a nascent polypeptide-associated complex α subunit (Nac1) functions as a transcriptional regulator and plays both positive and negative roles in a vast array of functions in Alternaria alternata. Gain- and loss-of-function studies reveal that Nac1 is required for the formation and germination of conidia, likely via the regulation of Fus3 and Slt2 mitogen-activated protein kinase (MAPK)-coding genes, both implicated in conidiation. Nac1 negatively regulates hyphal branching and the production of cell wall-degrading enzymes. Importantly, Nac1 is required for the biosynthesis of siderophores, a novel phenotype that has not been reported to be associated with a Nac in fungi. The expression of Nac1 is positively regulated by iron, as well as by the Hog1 MAPK and the NADPH-dependent oxidase (Nox) complex. Nac1 confers cellular susceptibility to reactive oxygen species (ROS) likely via negatively regulating the expression of the genes encoding Yap1, Skn7, Hog1, and Nox, all involved in ROS resistance. The involvement of Nac1 in sensitivity to glucose-, mannitol-, or sorbitol-induced osmotic stress could be due to its ability to suppress the expression of Skn7. The requirement of Nac1 in resistance to salts is unlikely mediated through the transcriptional activation of Hog1. Although Nac1 plays no role in toxin production, Nac1 is required for fungal full virulence. All observed deficiencies can be restored by re-expressing a functional copy of Nac1, confirming that Nac1 contributes to the phenotypes. Thus, a dynamic regulation of gene expression via Nac1 is critical for developmental, physiological, and pathological processes of A. alternata.
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Affiliation(s)
- Pin-Hua Wang
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung Hsing University, Taichung, 40227, Taiwan
| | - Pei-Ching Wu
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung Hsing University, Taichung, 40227, Taiwan
| | - Richie Huang
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung Hsing University, Taichung, 40227, Taiwan
| | - Kuang-Ren Chung
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung Hsing University, Taichung, 40227, Taiwan
- Ph.D. Program in Microbial Genomics, National Chung Hsing University and Academia Sinica, Taichung 40227, Taiwan
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Liu Y, Xin J, Liu L, Song A, Liao Y, Guan Z, Fang W, Chen F. Ubiquitin E3 Ligase AaBre1 Responsible for H2B Monoubiquitination Is Involved in Hyphal Growth, Conidiation and Pathogenicity in Alternaria alternata. Genes (Basel) 2020; 11:genes11020229. [PMID: 32098172 PMCID: PMC7074354 DOI: 10.3390/genes11020229] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 02/14/2020] [Accepted: 02/18/2020] [Indexed: 11/16/2022] Open
Abstract
Ubiquitination is one of several post-transcriptional modifications of histone 2B (H2B) which affect the chromatin structure and, hence, influence gene transcription. This study focuses on Alternaria alternata, a fungal pathogen responsible for leaf spot in many plant species. The experiments show that the product of AaBRE1, a gene which encodes H2B monoubiquitination E3 ligase, regulates hyphal growth, conidial formation and pathogenicity. Knockout of AaBRE1 by the homologous recombination strategy leads to the loss of H2B monoubiquitination (H2Bub1), as well as a remarkable decrease in the enrichment of trimethylated lysine 4 on histone 3 (H3K4me3). RNA sequencing assays elucidated that the transcription of genes encoding certain C2H2 zinc-finger family transcription factors, cell wall-degrading enzymes and chitin-binding proteins was suppressed in the AaBRE1 knockout cells. GO enrichment analysis showed that these proteins encoded by the set of genes differentially transcribed between the deletion mutant and wild type were enriched in the functional categories “macramolecular complex”, “cellular metabolic process”, etc. A major conclusion was that the AaBRE1 product, through its effect on histone 2B monoubiquitination and histone 3 lysine 4 trimethylation, makes an important contribution to the fungus’s hyphal growth, conidial formation and pathogenicity.
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Zhang T, Cao Q, Li N, Liu D, Yuan Y. Transcriptome analysis of fungicide-responsive gene expression profiles in two Penicillium italicum strains with different response to the sterol demethylation inhibitor (DMI) fungicide prochloraz. BMC Genomics 2020; 21:156. [PMID: 32050894 PMCID: PMC7017498 DOI: 10.1186/s12864-020-6564-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Accepted: 02/07/2020] [Indexed: 12/19/2022] Open
Abstract
Background Penicillium italicum (blue mold) is one of citrus pathogens causing undesirable citrus fruit decay even at strictly-controlled low temperatures (< 10 °C) during shipping and storage. P. italicum isolates with considerably high resistance to sterol demethylation inhibitor (DMI) fungicides have emerged; however, mechanism(s) underlying such DMI-resistance remains unclear. In contrast to available elucidation on anti-DMI mechanism for P. digitatum (green mold), how P. italicum DMI-resistance develops has not yet been clarified. Results The present study prepared RNA-sequencing (RNA-seq) libraries for two P. italicum strains (highly resistant (Pi-R) versus highly sensitive (Pi-S) to DMI fungicides), with and without prochloraz treatment, to identify prochloraz-responsive genes facilitating DMI-resistance. After 6 h prochloraz-treatment, comparative transcriptome profiling showed more differentially expressed genes (DEGs) in Pi-R than Pi-S. Functional enrichments identified 15 DEGs in the prochloraz-induced Pi-R transcriptome, simultaneously up-regulated in P. italicum resistance. These included ATP-binding cassette (ABC) transporter-encoding genes, major facilitator superfamily (MFS) transporter-encoding genes, ergosterol (ERG) anabolism component genes ERG2, ERG6 and EGR11 (CYP51A), mitogen-activated protein kinase (MAPK) signaling-inducer genes Mkk1 and Hog1, and Ca2+/calmodulin-dependent kinase (CaMK) signaling-inducer genes CaMK1 and CaMK2. Fragments Per Kilobase per Million mapped reads (FPKM) analysis of Pi-R transcrtiptome showed that prochloraz induced mRNA increase of additional 4 unigenes, including the other two ERG11 isoforms CYP51B and CYP51C and the remaining kinase-encoding genes (i.e., Bck1 and Slt2) required for Slt2-MAPK signaling. The expression patterns of all the 19 prochloraz-responsive genes, obtained in our RNA-seq data sets, have been validated by quantitative real-time PCR (qRT-PCR). These lines of evidence in together draw a general portrait of anti-DMI mechanisms for P. italicum species. Intriguingly, some strategies adopted by the present Pi-R were not observed in the previously documented prochloraz-resistant P. digitatum transcrtiptomes. These included simultaneous induction of all major EGR11 isoforms (CYP51A/B/C), over-expression of ERG2 and ERG6 to modulate ergosterol anabolism, and concurrent mobilization of Slt2-MAPK and CaMK signaling processes to overcome fungicide-induced stresses. Conclusions The present findings provided transcriptomic evidence on P. italicum DMI-resistance mechanisms and revealed some diversity in anti-DMI strategies between P. italicum and P. digitatum species, contributing to our knowledge on P. italicum DMI-resistance mechanisms.
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Affiliation(s)
- Tingfu Zhang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
| | - Qianwen Cao
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China
| | - Na Li
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China.,Yunnan Higher Education Institutions, College of Life Science and Technology, Honghe University, Mengzi, 661199, China
| | - Deli Liu
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China.
| | - Yongze Yuan
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, 430079, China.
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Ma H, Zhang B, Gai Y, Sun X, Chung KR, Li H. Cell-Wall-Degrading Enzymes Required for Virulence in the Host Selective Toxin-Producing Necrotroph Alternaria alternata of Citrus. Front Microbiol 2019; 10:2514. [PMID: 31824437 PMCID: PMC6883767 DOI: 10.3389/fmicb.2019.02514] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 10/18/2019] [Indexed: 12/12/2022] Open
Abstract
The necrotrophic fungal pathogen Alternaria alternata attacks many citrus species, causing brown spot disease. Its pathogenic capability depends primarily on the production of host-selective ACT toxin. In the current study a Ste12 transcription factor was characterized to be required for conidial formation and the production of cell-wall-degrading enzymes (CWDEs) in the tangerine pathotype of A. alternata. The Ste12 deficiency strain (ΔSte12) retained wild-type growth, ACT toxin production, and sensitivity to oxidative and osmotic stress. However, pathogenicity tests assayed on detached Dancy leaves revealed a marked reduction in virulence of ΔSte12. Transcriptome and quantitative RT-PCR analyses revealed that many genes associated with Carbohydrate-Active Enzymes (CAZymes) were downregulated in ΔSte12. Two cutinase-coding genes (AaCut3 and AaCut7) regulated by Ste12 were individually and simultaneously inactivated. The AaCut3 or AaCut7 deficiency strain unchanged in cutinase activities and incited wild-type lesions on Dancy leaves. However, the strain carrying an AaCut3 AaCut7 double mutation produced and secreted significantly fewer cutinases and incited smaller necrotic lesions than wild type. Not only is the host-selective toxin (HST) produced by A. alternata required for fungal penetration and lesion formation, but so too are CWDEs required for full virulence. Overall, this study expands our understanding of how A. alternata overcomes citrus physical barriers to carry out successful penetration and colonization.
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Affiliation(s)
- Haijie Ma
- Key Lab of Molecular Biology of Crop Pathogens and Insects, Ministry of Agriculture, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Bin Zhang
- Key Lab of Molecular Biology of Crop Pathogens and Insects, Ministry of Agriculture, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Yunpeng Gai
- Key Lab of Molecular Biology of Crop Pathogens and Insects, Ministry of Agriculture, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Xuepeng Sun
- Key Lab of Molecular Biology of Crop Pathogens and Insects, Ministry of Agriculture, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Kuang-Ren Chung
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung-Hsing University, Taichung, Taiwan
| | - Hongye Li
- Key Lab of Molecular Biology of Crop Pathogens and Insects, Ministry of Agriculture, Institute of Biotechnology, Zhejiang University, Hangzhou, China
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28
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Wang K, Zheng X, Zhang X, Zhao L, Yang Q, Boateng NAS, Ahima J, Liu J, Zhang H. Comparative Transcriptomic Analysis of the Interaction between Penicillium expansum and Apple Fruit ( Malus pumila Mill.) during Early Stages of Infection. Microorganisms 2019; 7:microorganisms7110495. [PMID: 31661784 PMCID: PMC6920851 DOI: 10.3390/microorganisms7110495] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 10/20/2019] [Accepted: 10/21/2019] [Indexed: 01/26/2023] Open
Abstract
Blue mold, caused by Penicillium expansum, is an important postharvest disease of apple, and can result in significant economic losses. The present study investigated the interaction between P. expansum and wounded apple fruit tissues during the early stages of the infection. Spores of P. expansum became activated one hour post-inoculation (hpi), exhibited swelling at 3 hpi, and the germ tubes were found entering into apple tissues at 6 hpi. RNA-seq was performed on samples of P. expansum and apple fruit tissue collected at 1, 3, and 6 hpi. The main differentially expressed genes (DEGs) that were identified in P. expansum were related to interaction, cell wall degradation enzymes, anti-oxidative stress, pH regulation, and effectors. Apple tissues responded to the presence of P. expansum by activating pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) at 1 hpi, then activated effector-triggered immunity (ETI) at 3 hpi. This research provides new information on the interaction between P. expansum and apple fruit tissue at an early stage of the infection process.
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Affiliation(s)
- Kaili Wang
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China.
| | - Xiangfeng Zheng
- School of Food Science and Engineering, Yangzhou University, Yangzhou 225009, China.
| | - Xiaoyun Zhang
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China.
| | - Lina Zhao
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China.
| | - Qiya Yang
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China.
| | | | - Joseph Ahima
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China.
| | - Jia Liu
- Chongqing Key Laboratory of Economic Plant Biotechnology, College of Landscape Architecture and Life Science/Institute of Special Plants, Chongqing University of Arts and Sciences, Yongchuan, Chongqing 402160, China.
| | - Hongyin Zhang
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China.
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Kwak CS, Kim MJ, Kim SG, Park S, Kim IG, Kang HS. Antioxidant and antiobesity activities of oral treatment with ethanol extract from sprout of evening primrose (Oenothera laciniata) in high fat diet-induced obese mice. ACTA ACUST UNITED AC 2019. [DOI: 10.4163/jnh.2019.52.6.529] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Chung Shil Kwak
- Institute on Aging, Seoul National University, Seoul 03080, Korea
| | - Mi-Ju Kim
- Institute on Aging, Seoul National University, Seoul 03080, Korea
| | | | | | - In Gyu Kim
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul 03080, Korea
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30
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Braga RM, Padilla G, Araújo WL. The biotechnological potential of Epicoccum spp.: diversity of secondary metabolites. Crit Rev Microbiol 2018; 44:759-778. [PMID: 30369284 DOI: 10.1080/1040841x.2018.1514364] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Epicoccum is a genus of ubiquitous fungi typically found in air, in soil, and on decaying vegetation. They also commonly display an endophytic lifestyle and are isolated from diverse plant tissues. The fungi from the genus Epicoccum are mainly known for their use as biocontrol agents against phytopathogens and for their ability to produce many secondary metabolites with potential biotechnological applications, such as antioxidant, anticancer,r and antimicrobial compounds. Among the bioactive compounds produced by Epicoccum spp., epicocconone is a commercially available fluorophore, D8646-2-6 is a patented telomerase inhibitor, and taxol is an anticancer drug originally isolated from Taxus brevifolia. Epicoccum spp. also produces epicolactone, an antimicrobial compound with a unique and complex structure that has aroused considerable interest in the chemical-synthesis community. The main goal of the present review is to discuss the diversity of secondary metabolites produced by Epicoccum spp., their biotechnological applications, and proposed hypothetical biosynthesis. In addition, the use of Epicoccum spp. as biocontrol agents and the pigments produced by these fungi are also discussed.
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Affiliation(s)
- Raíssa Mesquita Braga
- a NAP-BIOP - LABMEM, Department of Microbiology, Institute of Biomedical Sciences , University of São Paulo , São Paulo , Brazil
| | - Gabriel Padilla
- a NAP-BIOP - LABMEM, Department of Microbiology, Institute of Biomedical Sciences , University of São Paulo , São Paulo , Brazil
| | - Welington Luiz Araújo
- a NAP-BIOP - LABMEM, Department of Microbiology, Institute of Biomedical Sciences , University of São Paulo , São Paulo , Brazil
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Lin HC, Yu PL, Chen LH, Tsai HC, Chung KR. A Major Facilitator Superfamily Transporter Regulated by the Stress-Responsive Transcription Factor Yap1 Is Required for Resistance to Fungicides, Xenobiotics, and Oxidants and Full Virulence in Alternaria alternata. Front Microbiol 2018; 9:2229. [PMID: 30279684 PMCID: PMC6153361 DOI: 10.3389/fmicb.2018.02229] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Accepted: 08/31/2018] [Indexed: 11/29/2022] Open
Abstract
Alternaria alternata relies on the ability to produce a host-selective toxin and to detoxify reactive oxygen species to successfully colonize the host. An A. alternata major facilitator superfamily transporter designated AaMFS54 was functionally characterized by analysis of loss- and gain-of-function mutations to better understand the factors required for fungal pathogenesis. AaMFS54 was originally identified from a wild-type expression library after being subtracted with that of a mutant impaired for the oxidative stress-responsive transcription regulator Yap1. AaMFS54 contains 14 transmembrane helixes. Fungal mutant lacking AaMFS54 produced fewer conidia and increased sensitivity to many potent oxidants (potassium superoxide and singlet-oxygen generating compounds), xenobiotics (2,3,5-triiodobenzoic acid and 2-chloro-5-hydroxypyridine), and fungicides (clotrimazole, fludioxonil, vinclozolin, and iprodione). AaMFS54 mutant induced necrotic lesion sizes similar to those induced by wild-type on leaves of susceptible citrus cultivars after point inoculation with spore suspensions. However, the mutant produced smaller colonies and less fluffy hyphae on the affected leaves. Virulence assays on citrus leaves inoculated by spraying with spores revealed that AaMFS54 mutant induced less severe lesions than wild-type, indicating the requirement of AaMFS54 in pathogenesis. All defective phenotypes were restored in a strain re-acquiring a functional copy of AaMFS54. Northern blotting analysis revealed that the expression of AaMFS54 was suppressed by xenobiotics. The current studies indicate that the Yap1-mediated transporter plays a role in resistance to toxic oxidants and fungicides in A. alternata. The relationships of MFS transporters with other regulatory components conferring stress resistance and A. alternata pathogenesis are also discussed.
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Affiliation(s)
- Hsien-Che Lin
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung-Hsing University, Taichung, Taiwan
| | - Pei-Ling Yu
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung-Hsing University, Taichung, Taiwan
| | - Li-Hung Chen
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung-Hsing University, Taichung, Taiwan
| | - Hsieh-Chin Tsai
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung-Hsing University, Taichung, Taiwan
| | - Kuang-Ren Chung
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung-Hsing University, Taichung, Taiwan
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Feng H, Zhang M, Zhao Y, Li C, Song L, Huang L. Secreted peroxidases VmPODs play critical roles in the conidiation, H 2O 2 sensitivity and pathogenicity of Valsa mali. Fungal Genet Biol 2018; 119:20-28. [PMID: 30125671 DOI: 10.1016/j.fgb.2018.08.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 07/02/2018] [Accepted: 08/15/2018] [Indexed: 01/22/2023]
Abstract
Apple Valsa canker, caused by the necrotrophic pathogen Valsa mali, is a devastating disease of apples and causes great financial loss in East Asia. Improving the understanding of apple - V. mali interactions will contribute to disease management. In this study, three predicted secreted peroxidases (VmPOD1, VmPOD2 and VmPOD3) were uncovered based on the secretome and genome information of V. mali. Phylogenetic analysis showed that VmPOD1 is a catalase peroxidase, VmPOD2 is a chloroperoxidase, and VmPOD3 is a plant peroxidase-like peroxidase. The secretion function of the corresponding genes was confirmed using the yeast invertase secretion system. The deletion of VmPODs did not affect the vegetative growth when the mutants (ΔVmPOD1, ΔVmPOD2 and ΔVmPOD3) and the wild-type strain 03-8 were grown on PDA medium at 25 °C in the dark. However, the respective mutants showed impaired conidiation ability with fewer pycnidia, and all gene deletion mutants grew more slowly than 03-8 on PDA supplemented with H2O2 (Final concentration: 0.06 mol/L H2O2). In addition, VmPOD1 and VmPOD2 were found to be significantly up-regulated at an early infection stage, and VmPOD3 showed sustained high expression during the whole infection progress of V. mali. In addition, the virulence of ΔVmPOD3 was significantly reduced, implying that VmPOD3 plays a critical role during the interaction between V. mali and apple. All of the defective phenotypes could be nearly restored by re-introducing the wild-type VmPOD1, VmPOD2 or VmPOD3 allele. The results enhanced our understanding of the secreted peroxidase, which could also act as a type of virulence factor from the necrotrophic pathogen V. mali and provided new insight into the role of the pathogen-secreted peroxidase.
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Affiliation(s)
- Hao Feng
- College of Plant Protection and State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Mian Zhang
- College of Plant Protection and State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Yuhuan Zhao
- College of Plant Protection and State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Chen Li
- College of Plant Protection and State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Linlin Song
- College of Plant Protection and State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Lili Huang
- College of Plant Protection and State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi 712100, China.
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Thioredoxin and Glutaredoxin Systems Required for Oxidative Stress Resistance, Fungicide Sensitivity, and Virulence of Alternaria alternata. Appl Environ Microbiol 2018; 84:AEM.00086-18. [PMID: 29752269 DOI: 10.1128/aem.00086-18] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 05/04/2018] [Indexed: 01/07/2023] Open
Abstract
This study determined the function of thioredoxin and glutaredoxin systems in the phytopathogenic fungus Alternaria alternata via analyzing mutants obtained from the targeted deletion of genes encoding thioredoxin peroxidase (Tsa1), thioredoxin reductase (Trr1), and glutathione reductase (Glr1). Trr1 and Glr1, but not Tsa1, are required for growth and conidiation. The reduced growth and conidiation seen in the Trr1 or Glr1 deletion mutant can be restored by glutathione. Deletion mutants showing growth inhibition by oxidants are defective for H2O2 detoxification and induce smaller lesions on citrus leaves. Trr1 and Glr1, but not Tsa1, also contribute to NaCl resistance. Glr1 is required for sorbitol resistance and is responsible for resistance to mancozeb and boscalid but not chlorothalonil fungicides, a novel phenotype that has not been reported in fungi. Trr1 is required for resistance to boscalid and chlorothalonil fungicides but confers susceptibility to mancozeb. The Tsa1 deletion mutant displays wild-type sensitivity to the tested fungicides. The expression of Tsa1 and Trr1 is regulated by the oxidative stress responsive regulators Yap1, Hog1, and Skn7. The expression of Tsa1, but not Trr1, is also regulated indirectly by the NADPH oxidase. The results indicate that the capability to resist oxidative stress is required for virulence of A. alternataIMPORTANCE The thioredoxin and glutaredoxin systems are important thiol antioxidant systems in cells, and knowledge of these two systems in the plant-pathogenic fungus A. alternata is useful for finding new strategies to reduce the virulence of this pathogen. In this study, we demonstrated that thiol antioxidant system-related genes (Tsa1, Trr1, and Glr1) are required for H2O2 detoxification and virulence in A. alternata Moreover, deletion of Trr1 results in hypersensitivity to the fungicides chlorothalonil and boscalid, and Glr1 deletion mutants are highly sensitive to mancozeb, which is the fungicide mostly used in citrus fields. Therefore, our findings demonstrate that the ability to detoxify reactive oxygen species (ROS) plays a critical role in pathogenesis on citrus and provide novel insights into the physiological functions of thiol-containing systems in fungicide sensitivity for A. alternata.
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The oxygen concentration in cultures modulates protein expression and enzymatic antioxidant responses in Metarhizium lepidiotae conidia. Fungal Biol 2018; 122:487-496. [DOI: 10.1016/j.funbio.2017.10.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 10/29/2017] [Accepted: 10/31/2017] [Indexed: 11/21/2022]
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Genome-wide comparative and evolutionary analysis of Calmodulin-binding Transcription Activator (CAMTA) family in Gossypium species. Sci Rep 2018; 8:5573. [PMID: 29615731 PMCID: PMC5882909 DOI: 10.1038/s41598-018-23846-w] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 03/19/2018] [Indexed: 11/08/2022] Open
Abstract
The CAMTA gene family is crucial in managing both biotic and abiotic stresses in plants. Our comprehensive analysis of this gene family in cotton resulted in the identification of 6, 7 and 9 CAMTAs in three sequenced cotton species, i.e., Gossypium arboreum, Gossypium raimondii, and Gossypium hirsutum, respectively. All cotton CAMTAs were localized in the nucleus and possessed calmodulin-binding domain (CaMBD) as identified computationally. Phylogenetically four significant groups of cotton CAMTAs were identified out of which, Group II CAMTAs experienced higher evolutionary pressure, leading to a faster evolution in diploid cotton. The expansion of cotton CAMTAs in the genome was mainly due to segmental duplication. Purifying selection played a significant role in the evolution of cotton CAMTAs. Expression profiles of GhCAMTAs revealed that GhCAMTA2A.2 and GhCAMTA7A express profoundly in different stages of cotton fiber development. Positive correlation between expression of these two CAMTAs and fiber strength confirmed their functional relevance in fiber development. The promoter region of co-expressing genes network of GhCAMTA2A.2 and GhCAMTA7A showed a higher frequency of occurrence of CAMTA binding motifs. Our present study thus contributes to broad probing into the structure and probable function of CAMTA genes in Gossypium species.
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Wang M, Yang X, Ruan R, Fu H, Li H. Csn5 Is Required for the Conidiogenesis and Pathogenesis of the Alternaria alternata Tangerine Pathotype. Front Microbiol 2018; 9:508. [PMID: 29616013 PMCID: PMC5870056 DOI: 10.3389/fmicb.2018.00508] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 03/06/2018] [Indexed: 11/13/2022] Open
Abstract
The COP9 signalosome (CSN) is a highly conserved protein complex involved in the ubiquitin-proteasome system. Its metalloisopeptidase activity resides in subunit 5 (CSN5). Functions of csn5 in phytopathogenic fungi are poorly understood. Here, we knocked out the csn5 ortholog (Aacsn5) in the tangerine pathotype of Alternaria alternata. The ΔAacsn5 mutant showed a moderately reduced growth rate compared to the wildtype strain and was unable to produce conidia. The growth of ΔAacsn5 mutant was not affected in response to oxidative and osmotic stresses. Virulence assays revealed that ΔAacsn5 induced no or significantly reduced necrotic lesions on detached citrus leaves. The defects in hyphal growth, conidial sporulation, and pathogenicity of ΔAacsn5 were restored by genetic complementation of the mutant with wildtype Aacsn5. To explore the molecular mechanisms of conidiation and pathogenesis underlying Aacsn5 regulation, we systematically examined the transcriptomes of both ΔAacsn5 and the wildtype. Generally, 881 genes were overexpressed and 777 were underexpressed in the ΔAacsn5 mutant during conidiation while 694 overexpressed and 993 underexpressed during infection. During asexual development, genes related to the transport processes and nitrogen metabolism were significantly downregulated; the expression of csn1-4 and csn7 in ΔAacsn5 was significantly elevated; secondary metabolism gene clusters were broadly affected; especially, the transcript level of the whole of cluster 28 and 30 was strongly induced. During infection, the expression of the host-specific ACT toxin gene cluster which controls the biosynthesis of the citrus specific toxin was significantly repressed; many other SM clusters with unknown products were also regulated; 86 out of 373 carbohydrate-active enzymes responsible for breaking down the plant dead tissues showed uniquely decreased expression. Taken together, our results expand our understanding of the roles of csn5 on conidiation and pathogenicity in plant pathogenic fungi and provide a foundation for future investigations.
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Affiliation(s)
- Mingshuang Wang
- Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Xiao Yang
- Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Ruoxin Ruan
- Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China.,Hangzhou Academy of Agricultural Sciences, Hangzhou, China
| | - Huilan Fu
- Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Hongye Li
- Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
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Venice F, de Pinto MC, Novero M, Ghignone S, Salvioli A, Bonfante P. Gigaspora margarita with and without its endobacterium shows adaptive responses to oxidative stress. MYCORRHIZA 2017; 27:747-759. [PMID: 28730540 DOI: 10.1007/s00572-017-0790-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 07/12/2017] [Indexed: 05/08/2023]
Abstract
Arbuscular mycorrhizal (AM) fungi experience oxidative stress during the plant-fungal interaction, due to endogenous reactive oxygen species (ROS) produced by fungal metabolism and exogenous ROS produced by plant cells. Here, we examine the responses to H2O2 in Gigaspora margarita, an AM fungus containing the endobacterial symbiont Candidatus Glomeribacter gigasporarum (CaGg). Previous studies revealed that G. margarita with its endobacterium produces more ATP and has higher respiratory activity than a cured line that lacks the endobacterium. This higher bioenergetic potential leads to higher production of ROS and to a higher ROS-detoxifying capacity, suggesting a direct or indirect role of the endobacterium in modulating fungal antioxidant responses. To test the hypothesis that the fungal-endobacterial symbiosis may enhance the fitness of the AM fungus in the presence of oxidative stress, we treated the fungus with a sublethal concentration of H2O2 and performed RNA-seq analysis. Our results demonstrate that (i) irrespective of the endobacterium presence, G. margarita faces oxidative stress by activating multiple metabolic processes (methionine oxidation, sulfur uptake, the pentose phosphate pathway, activation of ROS-scavenger genes); (ii) in the presence of its endobacterium, G. margarita upregulates some metabolic pathways, like chromatin status modifications and iron metabolism; and (iii) contrary to our hypothesis, the cured line responds to H2O2 by activating the transcription of specific ROS scavengers. We confirmed the RNA-seq findings by measuring the glutathione and ascorbate concentration, which was the same in both lines after H2O2 treatment. We conclude that both fungal lines may face oxidative stress, but they activate alternative strategies.
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Affiliation(s)
- Francesco Venice
- Department of Life Sciences and Systems Biology, University of Torino, viale Mattioli 25, 10125, Torino, Italy
| | | | - Mara Novero
- Department of Life Sciences and Systems Biology, University of Torino, viale Mattioli 25, 10125, Torino, Italy
| | | | - Alessandra Salvioli
- Department of Life Sciences and Systems Biology, University of Torino, viale Mattioli 25, 10125, Torino, Italy
| | - Paola Bonfante
- Department of Life Sciences and Systems Biology, University of Torino, viale Mattioli 25, 10125, Torino, Italy.
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Liu J, Sui Y, Wisniewski M, Xie Z, Liu Y, You Y, Zhang X, Sun Z, Li W, Li Y, Wang Q. The impact of the postharvest environment on the viability and virulence of decay fungi. Crit Rev Food Sci Nutr 2017; 58:1681-1687. [PMID: 28140651 DOI: 10.1080/10408398.2017.1279122] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Postharvest decay of fruits, vegetables, and grains by fungal pathogens causes significant economic losses. Infected produce presents a potential health risk since some decay fungi produce mycotoxins that are hazardous to human health. Infections are the result of the interplay between host resistance and pathogen virulence. Both of these processes, however, are significantly impacted by environmental factors, such as temperature, UV, oxidative stress, and water activity. In the present review, the impact of various physical postharvest treatments (e.g., heat and UV) on the viability and virulence of postharvest pathogens is reviewed and discussed. Oxidative injury, protein impairment, and cell wall degradation have all been proposed as the mechanisms by which these abiotic stresses reduce fungal viability and pathogenicity. The response of decay fungi to pH and the ability of pathogens to modulate the pH of the host environment also affect pathogenicity. The effects of the manipulation of the postharvest environment by ethylene, natural edible coatings, and controlled atmosphere storage on fungal viability are also discussed. Lastly, avenues of future research are proposed.
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Affiliation(s)
- Jia Liu
- a Chongqing Key Laboratory of Economic Plant Biotechnology , College of Forestry & Life Science/Institute of Special Plants, College of Materials and Chemical Engineering, Chongqing University of Arts and Sciences , Yongchuan , China
| | - Yuan Sui
- a Chongqing Key Laboratory of Economic Plant Biotechnology , College of Forestry & Life Science/Institute of Special Plants, College of Materials and Chemical Engineering, Chongqing University of Arts and Sciences , Yongchuan , China
| | - Michael Wisniewski
- b U. S. Department of Agriculture - Agricultural Research Service (USDA-ARS) , Kearneysville , West Virginia , USA
| | - Zhigang Xie
- a Chongqing Key Laboratory of Economic Plant Biotechnology , College of Forestry & Life Science/Institute of Special Plants, College of Materials and Chemical Engineering, Chongqing University of Arts and Sciences , Yongchuan , China
| | - Yiqing Liu
- a Chongqing Key Laboratory of Economic Plant Biotechnology , College of Forestry & Life Science/Institute of Special Plants, College of Materials and Chemical Engineering, Chongqing University of Arts and Sciences , Yongchuan , China
| | - Yuming You
- a Chongqing Key Laboratory of Economic Plant Biotechnology , College of Forestry & Life Science/Institute of Special Plants, College of Materials and Chemical Engineering, Chongqing University of Arts and Sciences , Yongchuan , China
| | | | - Zhiqiang Sun
- c Yantai Lvyun Biotechnology Co., Ltd , Yantai , China
| | - Wenhua Li
- c Yantai Lvyun Biotechnology Co., Ltd , Yantai , China
| | - Yan Li
- d Key Laboratory of Plant Pathology, Ministry of Agriculture, Department of Plant Pathology , China Agricultural University , Beijing , China
| | - Qi Wang
- d Key Laboratory of Plant Pathology, Ministry of Agriculture, Department of Plant Pathology , China Agricultural University , Beijing , China
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Chen LH, Tsai HC, Yu PL, Chung KR. A Major Facilitator Superfamily Transporter-Mediated Resistance to Oxidative Stress and Fungicides Requires Yap1, Skn7, and MAP Kinases in the Citrus Fungal Pathogen Alternaria alternata. PLoS One 2017; 12:e0169103. [PMID: 28060864 PMCID: PMC5218470 DOI: 10.1371/journal.pone.0169103] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Accepted: 12/12/2016] [Indexed: 12/19/2022] Open
Abstract
Major Facilitator Superfamily (MFS) transporters play an important role in multidrug resistance in fungi. We report an AaMFS19 gene encoding a MFS transporter required for cellular resistance to oxidative stress and fungicides in the phytopathogenic fungus Alternaria alternata. AaMFS19, containing 12 transmembrane domains, displays activity toward a broad range of substrates. Fungal mutants lacking AaMFS19 display profound hypersensitivities to cumyl hydroperoxide, potassium superoxide, many singlet oxygen-generating compounds (eosin Y, rose Bengal, hematoporphyrin, methylene blue, and cercosporin), and the cell wall biosynthesis inhibitor, Congo red. AaMFS19 mutants also increase sensitivity to copper ions, clotrimazole, fludioxonil, and kocide fungicides, 2-chloro-5-hydroxypyridine (CHP), and 2,3,5-triiodobenzoic acid (TIBA). AaMFS19 mutants induce smaller necrotic lesions on leaves of a susceptible citrus cultivar. All observed phenotypes in the mutant are restored by introducing and expressing a wild-type copy of AaMFS19. The wild-type strain of A. alternata treated with either CHP or TIBA reduces radial growth and formation and germination of conidia, increases hyphal branching, and results in decreased expression of the AaMFS19 gene. The expression of AaMFS19 is regulated by the Yap1 transcription activator, the Hog1 and Fus3 mitogen-activated protein (MAP) kinases, the ‘two component’ histidine kinase, and the Skn7 response regulator. Our results demonstrate that A. alternata confers resistance to different chemicals via a membrane-bound MFS transporter.
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Affiliation(s)
- Li-Hung Chen
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung-Hsing University, Taichung, Taiwan
| | - Hsieh-Chin Tsai
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung-Hsing University, Taichung, Taiwan
| | - Pei-Ling Yu
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung-Hsing University, Taichung, Taiwan
| | - Kuang-Ren Chung
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung-Hsing University, Taichung, Taiwan
- Biotechnology Center, NCHU, Taichung, Taiwan
- NCHU-UCD Plant and Food Biotechnology Center, NCHU, Taichung, Taiwan
- * E-mail:
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Huang T, Zhou F, Wang-Johanning F, Nan K, Wei Y. Depression accelerates the development of gastric cancer through reactive oxygen species‑activated ABL1 (Review). Oncol Rep 2016; 36:2435-2443. [PMID: 27666407 DOI: 10.3892/or.2016.5127] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 09/05/2016] [Indexed: 11/06/2022] Open
Abstract
Depression is a common symptom among gastric cancer (GC) patients and serves as a potential indication of poor prognosis and advanced cancer clinical stage. However, the molecular mechanism of depression‑associated poor prognoses of GC patients remains unclear. Recent studies have revealed that GC patients with depression are under high levels of oxidative stress (OS) status that is accompanied by the dysfunction of numerous proto‑oncogenes, including the ABL proto‑oncogene 1 (ABL1), which is a non‑receptor tyrosine kinase. Recent evidence indicates that ABL1 was dysregulated in both major depressive disorder (MDD) and cancer patients with depression, and high levels of reactive oxygen species (ROS) can lead to the activation of ABL1 in response to OS and that activated ABL1 subsequently contributes to development of GC via interactions with the downstream targets and corresponding signaling pathways. In this review, we examine the evidence to illuminate the molecular mechanism of ABL1 in the progression of GC patients with depression and identify out new and effective methods for the initial and long‑term treatment of GC.
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Affiliation(s)
- Tianhe Huang
- Department of Oncology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Fuling Zhou
- Department of Clinical Hematology, Zhongnan Hospital, Wuhan University, Wuhan, Hubei 430071, P.R. China
| | | | - Kejun Nan
- Department of Oncology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Yongchang Wei
- Department of Oncology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
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Ren A, Liu R, Miao ZG, Zhang X, Cao PF, Chen TX, Li CY, Shi L, Jiang AL, Zhao MW. Hydrogen-rich water regulates effects of ROS balance on morphology, growth and secondary metabolism via glutathione peroxidase in Ganoderma lucidum. Environ Microbiol 2016; 19:566-583. [PMID: 27554678 DOI: 10.1111/1462-2920.13498] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 08/10/2016] [Indexed: 11/28/2022]
Abstract
Ganoderma lucidum is one of the most important medicinal fungi, but the lack of basic study on the fungus has hindered the further development of its value. To investigate the roles of the redox system in G. lucidum, acetic acid (HAc) was applied as a reactive oxygen species (ROS) stress inducer, and hydrogen-rich water (HRW) was used to relieve the ROS stress in this study. Our results demonstrate that the treatment of 5% HRW significantly decreased the ROS content, maintained biomass and polar growth morphology of mycelium, and decreased secondary metabolism under HAc-induced oxidative stress. Furthermore, the roles of HRW were largely dependent on restoring the glutathione system under HAc stress in G. lucidum. To provide further evidence, we used two glutathione peroxidase (GPX)-defective strains, the gpxi strain, the mercaptosuccinic acid (MS, a GPX inhibitor)-treated wide-type (WT) strain, and gpx overexpression strains for further research. The results show that HRW was unable to relieve the HAc-induced ROS overproduction, decreased biomass, mycelium morphology change and increased secondary metabolism biosynthesis in the absence of GPX function. The gpx overexpression strains exhibited resistance to HAc-induced oxidative stress. Thus, we propose that HRW regulates morphology, growth and secondary metabolism via glutathione peroxidase under HAc stress in the fungus G. lucidum. Furthermore, our research also provides a method to study the ROS system in other fungi.
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Affiliation(s)
- Ang Ren
- Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, P.R. China
| | - Rui Liu
- Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, P.R. China
| | - Zhi-Gang Miao
- Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, P.R. China
| | - Xue Zhang
- Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, P.R. China
| | - Peng-Fei Cao
- Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, P.R. China
| | - Tian-Xi Chen
- Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, P.R. China
| | - Chen-Yang Li
- Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, P.R. China
| | - Liang Shi
- Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, P.R. China
| | - Ai-Liang Jiang
- Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, P.R. China
| | - Ming-Wen Zhao
- Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, P.R. China
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Genomic and transcriptomic analyses of the tangerine pathotype of Alternaria alternata in response to oxidative stress. Sci Rep 2016; 6:32437. [PMID: 27582273 PMCID: PMC5007530 DOI: 10.1038/srep32437] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 08/09/2016] [Indexed: 12/19/2022] Open
Abstract
The tangerine pathotype of Alternaria alternata produces the A. citri toxin (ACT) and is the causal agent of citrus brown spot that results in significant yield losses worldwide. Both the production of ACT and the ability to detoxify reactive oxygen species (ROS) are required for A. alternata pathogenicity in citrus. In this study, we report the 34.41 Mb genome sequence of strain Z7 of the tangerine pathotype of A. alternata. The host selective ACT gene cluster in strain Z7 was identified, which included 25 genes with 19 of them not reported previously. Of these, 10 genes were present only in the tangerine pathotype, representing the most likely candidate genes for this pathotype specialization. A transcriptome analysis of the global effects of H2O2 on gene expression revealed 1108 up-regulated and 498 down-regulated genes. Expressions of those genes encoding catalase, peroxiredoxin, thioredoxin and glutathione were highly induced. Genes encoding several protein families including kinases, transcription factors, transporters, cytochrome P450, ubiquitin and heat shock proteins were found associated with adaptation to oxidative stress. Our data not only revealed the molecular basis of ACT biosynthesis but also provided new insights into the potential pathways that the phytopathogen A. alternata copes with oxidative stress.
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Ozyigit II, Filiz E, Vatansever R, Kurtoglu KY, Koc I, Öztürk MX, Anjum NA. Identification and Comparative Analysis of H2O2-Scavenging Enzymes (Ascorbate Peroxidase and Glutathione Peroxidase) in Selected Plants Employing Bioinformatics Approaches. FRONTIERS IN PLANT SCIENCE 2016; 7:301. [PMID: 27047498 PMCID: PMC4802093 DOI: 10.3389/fpls.2016.00301] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 02/25/2016] [Indexed: 05/08/2023]
Abstract
Among major reactive oxygen species (ROS), hydrogen peroxide (H2O2) exhibits dual roles in plant metabolism. Low levels of H2O2 modulate many biological/physiological processes in plants; whereas, its high level can cause damage to cell structures, having severe consequences. Thus, steady-state level of cellular H2O2 must be tightly regulated. Glutathione peroxidases (GPX) and ascorbate peroxidase (APX) are two major ROS-scavenging enzymes which catalyze the reduction of H2O2 in order to prevent potential H2O2-derived cellular damage. Employing bioinformatics approaches, this study presents a comparative evaluation of both GPX and APX in 18 different plant species, and provides valuable insights into the nature and complex regulation of these enzymes. Herein, (a) potential GPX and APX genes/proteins from 18 different plant species were identified, (b) their exon/intron organization were analyzed, (c) detailed information about their physicochemical properties were provided, (d) conserved motif signatures of GPX and APX were identified, (e) their phylogenetic trees and 3D models were constructed, (f) protein-protein interaction networks were generated, and finally (g) GPX and APX gene expression profiles were analyzed. Study outcomes enlightened GPX and APX as major H2O2-scavenging enzymes at their structural and functional levels, which could be used in future studies in the current direction.
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Affiliation(s)
- Ibrahim I. Ozyigit
- Department of Biology, Faculty of Science and Arts, Marmara UniversityIstanbul, Turkey
| | - Ertugrul Filiz
- Department of Crop and Animal Production, Cilimli Vocational School, Düzce UniversityDüzce, Turkey
| | - Recep Vatansever
- Department of Biology, Faculty of Science and Arts, Marmara UniversityIstanbul, Turkey
| | - Kuaybe Y. Kurtoglu
- Department of Biology, Faculty of Science and Arts, Marmara UniversityIstanbul, Turkey
- Department of Molecular Biology and Genetics, Faculty of Science, Istanbul Medeniyet UniversityIstanbul, Turkey
| | - Ibrahim Koc
- Department of Molecular Biology and Genetics, Faculty of Science, Gebze Technical UniversityKocaeli, Turkey
| | - Münir X. Öztürk
- Botany Department/Center for Environmental Studies, Ege UniversityIzmir, Turkey
- Faculty of Forestry, Universiti Putra MalaysiaSelangor, Malaysia
| | - Naser A. Anjum
- Centre for Environmental and Marine Studies and Department of Chemistry, University of AveiroAveiro, Portugal
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Yu PL, Chen LH, Chung KR. How the Pathogenic Fungus Alternaria alternata Copes with Stress via the Response Regulators SSK1 and SHO1. PLoS One 2016; 11:e0149153. [PMID: 26863027 PMCID: PMC4749125 DOI: 10.1371/journal.pone.0149153] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 01/27/2016] [Indexed: 01/06/2023] Open
Abstract
The tangerine pathotype of Alternaria alternata is a necrotrophic fungal pathogen causing brown spot disease on a number of citrus cultivars. To better understand the dynamics of signal regulation leading to oxidative and osmotic stress response and fungal infection on citrus, phenotypic characterization of the yeast SSK1 response regulator homolog was performed. It was determined that SSK1 responds to diverse environmental stimuli and plays a critical role in fungal pathogenesis. Experiments to determine the phenotypes resulting from the loss of SSK1 reveal that the SSK1 gene product may be fulfilling similar regulatory roles in signaling pathways involving a HOG1 MAP kinase during ROS resistance, osmotic resistance, fungicide sensitivity and fungal virulence. The SSK1 mutants display elevated sensitivity to oxidants, fail to detoxify H2O2 effectively, induce minor necrosis on susceptible citrus leaves, and displays resistance to dicarboximide and phenylpyrrole fungicides. Unlike the SKN7 response regulator, SSK1 and HOG1 confer resistance to salt-induced osmotic stress via an unknown kinase sensor rather than the “two component” histidine kinase HSK1. SSK1 and HOG1 play a moderate role in sugar-induced osmotic stress. We also show that SSK1 mutants are impaired in their ability to produce germ tubes from conidia, indicating a role for the gene product in cell differentiation. SSK1 also is involved in multi-drug resistance. However, deletion of the yeast SHO1 (synthetic high osmolarity) homolog resulted in no noticeable phenotypes. Nonetheless, our results show that A. alternata can sense and react to different types of stress via SSK1, HOG1 and SKN7 in a cooperative manner leading to proper physiological and pathological functions.
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Affiliation(s)
- Pei-Ling Yu
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung-Hsing University, Taichung, Taiwan
| | - Li-Hung Chen
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung-Hsing University, Taichung, Taiwan
| | - Kuang-Ren Chung
- Department of Plant Pathology, College of Agriculture and Natural Resources, National Chung-Hsing University, Taichung, Taiwan
- * E-mail:
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