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Choi S, Yang JW, Kim JE, Jeon H, Shin S, Wui D, Kim LS, Kim BJ, Son H, Min K. Infectivity and stress tolerance traits affect community assembly of plant pathogenic fungi. Front Microbiol 2023; 14:1234724. [PMID: 37692392 PMCID: PMC10486888 DOI: 10.3389/fmicb.2023.1234724] [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: 06/22/2023] [Accepted: 07/26/2023] [Indexed: 09/12/2023] Open
Abstract
Understanding how ecological communities assemble is an urgent research priority. In this study, we used a community ecology approach to examine how ecological and evolutionary processes shape biodiversity patterns of plant pathogenic fungi, Fusarium graminearum and F. asiaticum. High-throughput screening revealed that the isolates had a wide range of phenotypic variation in stress tolerance traits. Net Relatedness Index (NRI) and Nearest Taxon Index (NTI) values were computed based on stress-tolerant distance matrices. Certain local regions exhibited positive values of NRI and NTI, indicating phenotypic clustering within the fungal communities. Competition assays of the pooled strains were conducted to investigate the cause of clustering. During stress conditions and wheat colonization, only a few strains dominated the fungal communities, resulting in reduced diversity. Overall, our findings support the modern coexistence theory that abiotic stress and competition lead to phenotypic similarities among coexisting organisms by excluding large, low-competitive clades. We suggest that agricultural environments and competition for host infection lead to locally clustered communities of plant pathogenic fungi in the field.
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Affiliation(s)
- Soyoung Choi
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
| | - Jung Wook Yang
- Crop Cultivation and Environment Research Division, National Institute of Crop Science, Rural Development Administration, Suwon, Republic of Korea
| | - Jung-Eun Kim
- Research Institute of Climate Change and Agriculture, National Institute of Horticultural and Herbal Science, Rural Development Administration, Jeju, Republic of Korea
| | - Hosung Jeon
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
| | - Soobin Shin
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
| | - Dayoun Wui
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
| | - Lee Seul Kim
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
| | - Byung Joo Kim
- Crop Cultivation and Environment Research Division, National Institute of Crop Science, Rural Development Administration, Suwon, Republic of Korea
| | - Hokyoung Son
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea
| | - Kyunghun Min
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
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Uddin MJ, Huang X, Lu X, Li S. Increased Conidia Production and Germination In Vitro Correlate with Virulence Enhancement in Fusarium oxysporum f. sp. cucumerinum. J Fungi (Basel) 2023; 9:847. [PMID: 37623618 PMCID: PMC10455488 DOI: 10.3390/jof9080847] [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: 07/07/2023] [Revised: 08/10/2023] [Accepted: 08/12/2023] [Indexed: 08/26/2023] Open
Abstract
Cucumber plants commonly suffer from Fusarium wilt disease, which is caused by Fusarium oxysporum f. sp. cucumerinum (Foc). Although resistant cultivars assist with Fusarium wilt disease control, enhancement of the virulence of Foc has been identified after monoculture of wilt-resistant cultivars. To investigate the biological characteristics that contribute to the virulence evolution of Foc, a wildtype strain foc-3b (WT) and its virulence-enhanced variant Ra-4 (InVir) were compared in terms of their growth, reproduction, stress tolerance, and colonization in cucumber plants. The InVir strain showed similar culture characteristics on PDA media to the WT strain but produced significantly more conidia (>two fold), with a distinctly higher germination rate (>four fold) than the WT strain. The colony diameter of the InVir strain increased faster than the WT strain on PDA plates; however, the mycelia dry weight of the InVir was significantly lower (<70%) than that of the WT harvested from PDB. The InVir strain exhibited a significant increase in tolerance to osmolality (1 M NaCl, 1 M KCl, etc.). The GFP-labeled InVir strain propagated in the cucumber vascular faster than the WT strain. These results suggest that increased conidia production and germination in vitro may correlate with virulence enhancement in Fusarium oxysporum f. sp. cucumerinum. This study will provide an insight into its virulence evolution and help us understand the mechanisms underlying the evolutionary biology of F. oxysporum.
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Affiliation(s)
- Md. Jamal Uddin
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (M.J.U.); (X.H.)
- Crops Division, Bangladesh Agricultural Research Council (BARC), Dhaka 1215, Bangladesh
| | - Xiaoqing Huang
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (M.J.U.); (X.H.)
| | - Xiaohong Lu
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (M.J.U.); (X.H.)
| | - Shidong Li
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (M.J.U.); (X.H.)
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Bellah H, Seiler NF, Croll D. Divergent Outcomes of Direct Conspecific Pathogen Strain Interaction and Plant Co-Infection Suggest Consequences for Disease Dynamics. Microbiol Spectr 2023; 11:e0444322. [PMID: 36749120 PMCID: PMC10101009 DOI: 10.1128/spectrum.04443-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 01/23/2023] [Indexed: 02/08/2023] Open
Abstract
Plant diseases are often caused by co-infections of multiple pathogens with the potential to aggravate disease severity. In genetically diverse pathogen species, co-infections can also be caused by multiple strains of the same species. However, the outcome of such mixed infections by different conspecific genotypes is poorly understood. The interaction among pathogen strains with complex lifestyles outside and inside of the host are likely shaped by diverse traits, including metabolic capacity and the ability to overcome host immune responses. To disentangle competitive outcomes among pathogen strains, we investigated the fungal wheat pathogen Zymoseptoria tritici. The pathogen infects wheat leaves in complex strain assemblies, and highly diverse populations persist between growing seasons. We investigated a set of 14 genetically different strains collected from the same field to assess both competitive outcomes under culture conditions and on the host. Growth kinetics of cocultured strains (~100 pairs) significantly deviated from single strain expectations, indicating competitive exclusion depending on the strain genotype. We found similarly complex outcomes of lesion development on plant leaves following co-infections by the same pairs of strains. While some pairings suppressed overall damage to the host, other combinations exceeded expectations of lesion development based on single strain outcomes. Strain competition outcomes in the absence of the host were poor predictors of outcomes on the host, suggesting that the interaction with the plant immune system adds significant complexity. Intraspecific co-infection dynamics likely make important contributions to disease outcomes in the wild. IMPORTANCE Plants are often attacked by a multitude of pathogens simultaneously, and different species can facilitate or constrain the colonization by others. To what extent simultaneous colonization by different strains of the same species matters, remains unclear. We focused on intra-specific interactions between strains of the major fungal wheat pathogen Zymoseptoria tritici. The pathogen persists in the environment before infecting plant leaves early in the growing season. Leaves are typically colonized by a multitude of strains. Strains cultured in pairs without host were growing differently compared to strains cultured alone. Wheat leaves infected either with single or pairs of strains, we found also highly variable outcomes. Interactions between strains outside of the host were only poorly explaining how strains would interact when on the host, suggesting that pathogen strains engage in complex interactions dependent on the environment. Better understanding within-species interactions will improve our ability to manage crop infections.
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Affiliation(s)
- Hadjer Bellah
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Nicolas F. Seiler
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
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