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Caldwell DL, da Silva CR, McCoy AG, Avila H, Bonkowski JC, Chilvers MI, Helm M, Telenko DEP, Iyer-Pascuzzi AS. Uncovering the Infection Strategy of Phyllachora maydis During Maize Colonization: A Comprehensive Analysis. PHYTOPATHOLOGY 2024; 114:1075-1087. [PMID: 38079374 DOI: 10.1094/phyto-08-23-0298-kc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Tar spot, a disease caused by the ascomycete fungal pathogen Phyllachora maydis, is considered one of the most significant yield-limiting diseases of maize (Zea mays) within the United States. P. maydis may also be found in association with other fungi, forming a disease complex that is thought to result in the characteristic fisheye lesions. Understanding how P. maydis colonizes maize leaf cells is essential for developing effective disease control strategies. Here, we used histological approaches to elucidate how P. maydis infects and multiplies within susceptible maize leaves. We collected tar spot-infected maize leaf samples from four different fields in northern Indiana at three different time points during the growing season. Samples were chemically fixed and paraffin-embedded for high-resolution light and scanning electron microscopy. We observed a consistent pattern of disease progression in independent leaf samples collected across different geographical regions. Each stroma contained a central pycnidium that produced asexual spores. Perithecia with sexual spores developed in the stomatal chambers adjacent to the pycnidium, and a cap of spores formed over the stroma. P. maydis reproductive structures formed around but not within the vasculature. We observed P. maydis associated with two additional fungi, one of which is likely a member of the Paraphaeosphaeria genus; the other is an unknown fungi. Our data provide fundamental insights into how this pathogen colonizes and spreads within maize leaves. This knowledge can inform new approaches to managing tar spot, which could help mitigate the significant economic losses caused by this disease.
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Affiliation(s)
- Denise L Caldwell
- Department of Botany and Plant Pathology, Center for Plant Biology, Purdue University, West Lafayette, IN 47907
| | - Camila Rocco da Silva
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907
| | - Austin G McCoy
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824
| | - Harryson Avila
- Department of Botany and Plant Pathology, Center for Plant Biology, Purdue University, West Lafayette, IN 47907
| | - John C Bonkowski
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907
| | - Martin I Chilvers
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824
| | - Matthew Helm
- Crop Production and Pest Control Research Unit, U.S. Department of Agriculture-Agricultural Research Service, West Lafayette, IN 47907
| | - Darcy E P Telenko
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907
| | - Anjali S Iyer-Pascuzzi
- Department of Botany and Plant Pathology, Center for Plant Biology, Purdue University, West Lafayette, IN 47907
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Huang Z, Wang C, Li H, Zhou Y, Duan Z, Bao Y, Hu Q, Powell CA, Chen B, Zhang J, Zhang M, Yao W. Small secreted effector protein from Fusarium sacchari suppresses host immune response by inhibiting ScPi21-induced cell death. MOLECULAR PLANT PATHOLOGY 2024; 25:e13414. [PMID: 38279852 PMCID: PMC10782473 DOI: 10.1111/mpp.13414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 12/10/2023] [Accepted: 12/12/2023] [Indexed: 01/29/2024]
Abstract
Fusarium sacchari is one of the primary pathogens causing pokkah boeng disease, which impairs the yield and quality of sugarcane around the world. Understanding the molecular mechanisms of the F. sacchari effectors that regulate plant immunity is of great importance for the development of novel strategies for the persistent control of pokkah boeng disease. In a previous study, Fs00367 was identified to inhibit BAX-induced cell death. In this study, Fs00367nsp (without signal peptide) was found to suppress BAX-induced cell death, reactive oxygen species bursts and callose accumulation. The amino acid region 113-142 of Fs00367nsp is the functional region. Gene mutagenesis indicated that Fs00367 is important for the full virulence of F. sacchari. A yeast two-hybrid assay revealed an interaction between Fs00367nsp and sugarcane ScPi21 in yeast that was further confirmed using bimolecular fluorescence complementation, pull-down assay and co-immunoprecipitation. ScPi21 can induce plant immunity, but this effect could be blunted by Fs00367nsp. These results suggest that Fs00367 is a core pathogenicity factor that suppresses plant immunity through inhibiting ScPi21-induced cell death. The findings of this study provide new insights into the molecular mechanisms of effectors in regulating plant immunity.
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Affiliation(s)
- Zhen Huang
- State Key Laboratory for Conservation and Utilization of Subtropical Agri‐Biological Resources, Guangxi Key Laboratory of Sugarcane BiologyGuangxi UniversityNanningChina
| | - Caixia Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agri‐Biological Resources, Guangxi Key Laboratory of Sugarcane BiologyGuangxi UniversityNanningChina
| | - Huixue Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agri‐Biological Resources, Guangxi Key Laboratory of Sugarcane BiologyGuangxi UniversityNanningChina
| | - Yuming Zhou
- State Key Laboratory for Conservation and Utilization of Subtropical Agri‐Biological Resources, Guangxi Key Laboratory of Sugarcane BiologyGuangxi UniversityNanningChina
| | - Zhenzhen Duan
- State Key Laboratory for Conservation and Utilization of Subtropical Agri‐Biological Resources, Guangxi Key Laboratory of Sugarcane BiologyGuangxi UniversityNanningChina
| | - Yixue Bao
- State Key Laboratory for Conservation and Utilization of Subtropical Agri‐Biological Resources, Guangxi Key Laboratory of Sugarcane BiologyGuangxi UniversityNanningChina
| | - Qin Hu
- State Key Laboratory for Conservation and Utilization of Subtropical Agri‐Biological Resources, Guangxi Key Laboratory of Sugarcane BiologyGuangxi UniversityNanningChina
| | | | - Baoshan Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agri‐Biological Resources, Guangxi Key Laboratory of Sugarcane BiologyGuangxi UniversityNanningChina
| | - Jisen Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agri‐Biological Resources, Guangxi Key Laboratory of Sugarcane BiologyGuangxi UniversityNanningChina
| | - Muqing Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agri‐Biological Resources, Guangxi Key Laboratory of Sugarcane BiologyGuangxi UniversityNanningChina
- IRREC‐IFASUniversity of FloridaFort PierceFloridaUSA
| | - Wei Yao
- State Key Laboratory for Conservation and Utilization of Subtropical Agri‐Biological Resources, Guangxi Key Laboratory of Sugarcane BiologyGuangxi UniversityNanningChina
- IRREC‐IFASUniversity of FloridaFort PierceFloridaUSA
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