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Liu Y, Yuan J, Li Y, Bi Y, Prusky DB. The sensor protein AaSho1 regulates infection structures differentiation, osmotic stress tolerance and virulence via MAPK module AaSte11-AaPbs2-AaHog1 in Alternaria alternata. Comput Struct Biotechnol J 2024; 23:1594-1607. [PMID: 38680872 PMCID: PMC11047198 DOI: 10.1016/j.csbj.2024.04.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Revised: 04/01/2024] [Accepted: 04/11/2024] [Indexed: 05/01/2024] Open
Abstract
The high-osmolarity-sensitive protein Sho1 functions as a key membrane receptor in phytopathogenic fungi, which can sense and respond to external stimuli or stresses, and synergistically regulate diverse fungal biological processes through cellular signaling pathways. In this study, we investigated the biological functions of AaSho1 in Alternaria alternata, the causal agent of pear black spot. Targeted gene deletion revealed that AaSho1 is essential for infection structure differentiation, response to external stresses and synthesis of secondary metabolites. Compared to the wild-type (WT), the ∆AaSho1 mutant strain showed no significant difference in colony growth, morphology, conidial production and biomass accumulation. However, the mutant strain exhibited significantly reduced levels of melanin production, cellulase (CL) and ploygalacturonase (PG) activities, virulence, resistance to various exogenous stresses. Moreover, the appressorium and infection hyphae formation rates of the ∆AaSho1 mutant strain were significantly inhibited. RNA-Seq results showed that there were four branches including pheromone, cell wall stress, high osmolarity and starvation in the Mitogen-activated Protein Kinase (MAPK) cascade pathway. Furthermore, yeast two-hybrid experiments showed that AaSho1 activates the MAPK pathway via AaSte11-AaPbs2-AaHog1. These results suggest that AaSho1 of A. alternata is essential for fungal development, pathogenesis and osmotic stress response by activating the MAPK cascade pathway via Sho1-Ste11-Pbs2-Hog1.
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Affiliation(s)
- Yongxiang Liu
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, China
- College of Horticulture, Xinyang Agriculture and Forestry University, Xinyang, China
| | - Jing Yuan
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, China
| | - Yongcai Li
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, China
| | - Yang Bi
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, China
| | - Dov B. Prusky
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, China
- Institute of Postharvest and Food Sciences, Agricultural Research Organization Volcani Center Information Center, Rishon LeZion, Israel
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Yang Y, Xie P, Nan Y, Xu X, Yuan J, Li Y, Bi Y, Prusky D. Transcriptome Analysis Provides Insights into the Mechanism of the Transcription Factor AaCrz1 Regulating the Infection Structure Formation of Alternaria alternata Induced by Pear Peel Wax Signal. Int J Mol Sci 2024; 25:11950. [PMID: 39596020 PMCID: PMC11593592 DOI: 10.3390/ijms252211950] [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: 09/13/2024] [Revised: 10/31/2024] [Accepted: 11/05/2024] [Indexed: 11/28/2024] Open
Abstract
Alternaria alternata, a causal agent of pear black spot, can recognize and respond to physicochemical signals from fruit surfaces through an intricate signaling network to initiate infection. Crz1 is an important transcription factor downstream of the calcium signaling pathway. In this study, we first investigated the infection structure formation process of the wild type (WT) and ΔAaCrz1 strains induced by the cuticular wax of the "Zaosu" pear by microscopic observation. We found that the infection process was delayed and the rate of appressorium formation and infection hyphae formation was significantly decreased in the ΔAaCrz1 strain. RNA-seq of WT and ΔAaCrz1 strains was analyzed after 6 h of induction with pear wax. A total of 893 up-regulated and 534 down-regulated genes were identified. Among them, genes related to cell wall degrading enzymes, ABC transporters, and ion homeostasis were down-regulated, and the autophagy pathway was induced and activated. In addition, disruption to the intracellular antioxidant system was also found after AaCrz1 knockdown. In summary, this study provides new information on the mechanism of the transcription factor AaCrz1 in the regulation of infection structure formation of A. alternata induced by pear peel wax signal, which can be used to develop new strategies for controlling fungal diseases in the future.
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Affiliation(s)
- Yangyang Yang
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou 730070, China; (Y.Y.); (P.X.); (Y.N.); (X.X.); (J.Y.); (Y.B.)
| | - Pengdong Xie
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou 730070, China; (Y.Y.); (P.X.); (Y.N.); (X.X.); (J.Y.); (Y.B.)
| | - Yuanping Nan
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou 730070, China; (Y.Y.); (P.X.); (Y.N.); (X.X.); (J.Y.); (Y.B.)
| | - Xiaobin Xu
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou 730070, China; (Y.Y.); (P.X.); (Y.N.); (X.X.); (J.Y.); (Y.B.)
| | - Jing Yuan
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou 730070, China; (Y.Y.); (P.X.); (Y.N.); (X.X.); (J.Y.); (Y.B.)
| | - Yongcai Li
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou 730070, China; (Y.Y.); (P.X.); (Y.N.); (X.X.); (J.Y.); (Y.B.)
| | - Yang Bi
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou 730070, China; (Y.Y.); (P.X.); (Y.N.); (X.X.); (J.Y.); (Y.B.)
| | - Dov Prusky
- Department of Postharvest and Food Science, Agricultural Research Organization, Volcani Center, Rishon LeZion 7505101, Israel;
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Nan Y, Zhang M, Li Y, Bi Y. The G-protein alpha subunit AaGA1 positively regulates vegetative growth, appressorium-like formation, and pathogenicity in Alternaria alternata. J Appl Microbiol 2024; 135:lxae198. [PMID: 39104199 DOI: 10.1093/jambio/lxae198] [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: 05/16/2024] [Revised: 07/09/2024] [Accepted: 08/02/2024] [Indexed: 08/07/2024]
Abstract
AIMS The Gα subunit is a major component of heterotrimeric G proteins, which play a crucial role in the development and pathogenicity of several model fungi. However, its detailed function in the causal agent of pear black spot (Alternaria alternata) is unclear. Our aim was to understand the characteristics and functions of AaGA1 in A. alternata. METHODS AND RESULTS AaGA1 was cloned from A. alternata in this study, which encodes 353 amino acids and has a "G-alpha" domain. Mutant ΔAaGA1 resulted in reduced vegetative growth, conidiation, and spore germination. Especially, mutant ΔAaGA1 produced only fewer conidia on the V8A medium, and spore formation-related genes AbaA, BrlA, and WetA were significantly downregulated. More tolerance against cell wall-inhibiting agents was observed after the deletion of AaGA1. Moreover, AaGA1 deletion led to a significant reduction in melanin and toxin production. Interestingly, deletion of AaGA1 resulted in defective appressorium-like formations, complete loss of the ability to penetrate cellophane, and decreased infection on non-wound inoculated tobacco leaves. Cell wall-degrading enzyme-related genes PME, CL, Cut2, and LC were significantly downregulated in mutant ΔAaGA1 mutant, significantly reducing virulence on wound-inoculated pear fruits. CONCLUSIONS The G protein alpha subunit AaGA1 is indispensable for fungal development, appressorium-like formations, and pathogenicity in A. alternata.
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Affiliation(s)
- Yuanping Nan
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou 730070, China
| | - Miao Zhang
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou 730070, China
| | - Yongcai Li
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou 730070, China
| | - Yang Bi
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou 730070, China
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Li R, Li Y, Xu W, Liu W, Xu X, Bi Y, Prusky D. Aabrm1-mediated melanin synthesis is essential to growth and development, stress adaption, and pathogenicity in Alternaria alternata. Front Microbiol 2024; 14:1327765. [PMID: 38274752 PMCID: PMC10808324 DOI: 10.3389/fmicb.2023.1327765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 12/22/2023] [Indexed: 01/27/2024] Open
Abstract
Scytalone dehydratase (brm1) is one of the key enzymes in 1, 8-dihydroxynaphthalene (DHN) melanin synthesis, which mediates melanin biosythesis and regulates cell biological process of plant fungi, but its function in Alternaria alternata, the causal agent of pear black spot, is unclear. Brm1 in A. alternata was cloned, identified, and named as Aabrm1. An Aabrm1-deletion mutant was generated and revealed that the deletion of Aabrm1 leads to a significant decrease in melanin production and forms orange colony smooth spores. In addition, the deletion of Aabrm1 gene impaired infection structure information and penetration. The external stress resistance of ΔAabrm1 was significantly weakened, and, in particular, it is very sensitive to oxidative stress, and the contents of H2O2 and O2.- in ΔAabrm1 were significantly increased. Virulence of ΔAabrm1 was reduced in non-wound-inoculated pear leaves but not changed in wound-inoculated pear fruit. These results indicated that Aabrm1-mediated melanin synthesis plays an important role in the pathogenicity of A. alternata.
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Affiliation(s)
- Rong Li
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, China
| | - Yongcai Li
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, China
| | - Wenyi Xu
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, China
| | - Wenjuan Liu
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, China
| | - Xiaobin Xu
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, China
| | - 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, Bet Dagan, Israel
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Xue J, Zhang H, Zhao Q, Cui S, Yu K, Sun R, Yu Y. Construction of Yeast One-Hybrid Library of Alternaria oxytropis and Screening of Transcription Factors Regulating swnK Gene Expression. J Fungi (Basel) 2023; 9:822. [PMID: 37623593 PMCID: PMC10455089 DOI: 10.3390/jof9080822] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 07/30/2023] [Accepted: 07/31/2023] [Indexed: 08/26/2023] Open
Abstract
The indolizidine alkaloid-swainsonine (SW) is the main toxic component of locoweeds and the main cause of locoweed poisoning in grazing animals. The endophytic fungi, Alternaria Section Undifilum spp., are responsible for the biosynthesis of SW in locoweeds. The swnK gene is a multifunctional complex enzyme encoding gene in fungal SW biosynthesis, and its encoding product plays a key role in the multistep catalytic synthesis of SW by fungi using pipecolic acid as a precursor. However, the transcriptional regulation mechanism of the swnK gene is still unclear. To identify the transcriptional regulators involved in the swnK gene in endophytic fungi of locoweeds, we first analyzed the upstream non-coding region of the swnK gene in the A. oxytropis UA003 strain and predicted its high transcriptional activity region combined with dual-luciferase reporter assay. Then, a yeast one-hybrid library of A. oxytropis UA003 strain was constructed, and the transcriptional regulatory factors that may bind to the high-transcriptional activity region of the upstream non-coding region of the swnK gene were screened by this system. The results showed that the high transcriptional activity region was located at -656 bp and -392 bp of the upstream regulatory region of the swnK gene. A total of nine candidate transcriptional regulator molecules, including a C2H2 type transcription factor, seven annotated proteins, and an unannotated protein, were screened out through the Y1H system, which were bound to the upstream high transcriptional activity region of the swnK gene. This study provides new insight into the transcriptional regulation of the swnK gene and lays the foundation for further exploration of the regulatory mechanisms of SW biosynthesis in fungal endophytic locoweeds.
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Affiliation(s)
- Jiaqi Xue
- School of Animal Science and Technology, Ningxia University, Yinchuan 750021, China
| | - Haodong Zhang
- School of Animal Science and Technology, Ningxia University, Yinchuan 750021, China
| | - Qingmei Zhao
- College of Biological Science and Engineering, North Minzu University, Yinchuan 750021, China
| | - Shengwei Cui
- School of Animal Science and Technology, Ningxia University, Yinchuan 750021, China
| | - Kun Yu
- School of Animal Science and Technology, Ningxia University, Yinchuan 750021, China
| | - Ruohan Sun
- School of Animal Science and Technology, Ningxia University, Yinchuan 750021, China
| | - Yongtao Yu
- School of Animal Science and Technology, Ningxia University, Yinchuan 750021, China
- Ningxia Key Laboratory of Ruminant Molecular and Cellular Breeding, School of Animal Science and Technology, Ningxia University, Yinchuan 750021, China
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Jiang Q, Li Y, Mao R, Bi Y, Liu Y, Zhang M, Li R, Yang Y, Prusky DB. AaCaMKs Positively Regulate Development, Infection Structure Differentiation and Pathogenicity in Alternaria alternata, Causal Agent of Pear Black Spot. Int J Mol Sci 2023; 24:ijms24021381. [PMID: 36674895 PMCID: PMC9865007 DOI: 10.3390/ijms24021381] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Revised: 12/29/2022] [Accepted: 01/09/2023] [Indexed: 01/13/2023] Open
Abstract
Calcium/calmodulin-dependent protein kinase (CaMK), a key downstream target protein in the Ca2+ signaling pathway of eukaryotes, plays an important regulatory role in the growth, development and pathogenicity of plant fungi. Three AaCaMKs (AaCaMK1, AaCaMK2 and AaCaMK3) with conserved PKC_like superfamily domains, ATP binding sites and ACT sites have been cloned from Alternaria alternata, However, their regulatory mechanism in A. alternata remains unclear. In this study, the function of the AaCaMKs in the development, infection structure differentiation and pathogenicity of A. alternata was elucidated through targeted gene disruption. The single disruption of AaCaMKs had no impact on the vegetative growth and spore morphology but significantly influenced hyphae growth, sporulation, biomass accumulation and melanin biosynthesis. Further expression analysis revealed that the AaCaMKs were up-regulated during the infection structure differentiation of A. alternata on hydrophobic and pear wax substrates. In vitro and in vivo analysis further revealed that the deletion of a single AaCaMKs gene significantly reduced the A. alternata conidial germination, appressorium formation and infection hyphae formation. In addition, pharmacological analysis confirmed that the CaMK specific inhibitor, KN93, inhibited conidial germination and appressorium formation in A. alternata. Meanwhile, the AaCaMKs genes deficiency significantly reduced the A. alternata pathogenicity. These results demonstrate that AaCaMKs regulate the development, infection structure differentiation and pathogenicity of A. alternata and provide potential targets for new effective fungicides.
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Affiliation(s)
- Qianqian Jiang
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou 730070, China
| | - Yongcai Li
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou 730070, China
- Correspondence: ; Tel.: +86-931-763-1694
| | - Renyan Mao
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou 730070, China
| | - Yang Bi
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou 730070, China
| | - Yongxiang Liu
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou 730070, China
| | - Miao Zhang
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou 730070, China
| | - Rong Li
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou 730070, China
| | - Yangyang Yang
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou 730070, China
| | - Dov B. Prusky
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou 730070, China
- Institute of Postharvest and Food Sciences, The Volcani Center, Agricultural Research Organization, Rishon LeZion 7505101, Israel
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7
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Jiang Q, Mao R, Li Y, Bi Y, Liu Y, Zhang M, Li R, Yang Y, Dov B P.
AaCaM
is required for infection structure differentiation and secondary metabolites in pear fungal pathogen
Alternaria alternata. J Appl Microbiol 2022; 133:2631-2641. [DOI: 10.1111/jam.15732] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 06/12/2022] [Accepted: 07/20/2022] [Indexed: 11/29/2022]
Affiliation(s)
- Qianqian Jiang
- College of Food Science and Engineering Gansu Agricultural University Lanzhou China
| | - Renyan Mao
- College of Food Science and Engineering Gansu Agricultural University Lanzhou China
| | - Yongcai Li
- College of Food Science and Engineering Gansu Agricultural University Lanzhou China
| | - Yang Bi
- College of Food Science and Engineering Gansu Agricultural University Lanzhou China
| | - Yongxiang Liu
- College of Food Science and Engineering Gansu Agricultural University Lanzhou China
| | - Miao Zhang
- College of Food Science and Engineering Gansu Agricultural University Lanzhou China
| | - Rong Li
- College of Food Science and Engineering Gansu Agricultural University Lanzhou China
| | - Yangyang Yang
- College of Food Science and Engineering Gansu Agricultural University Lanzhou China
| | - Prusky Dov B
- College of Food Science and Engineering Gansu Agricultural University Lanzhou China
- Institute of Postharvest and Food Sciences The Volcani Center, Agricultural Research Organization Rishon LeZion Israel
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