Molecular Plant-microbe Interactions最新文献

{"title":"Salicylic Acid Plays a Major Role in Potato Defense Against Powdery Scab Pathogen, <i>Spongospora subterranea</i> f. sp<i>. subterranea</i>.","authors":"Samodya K Jayasinghe, Natalia Moroz, Peiguo Yuan, Michael V Kolomiets, Kiwamu Tanaka","doi":"10.1094/MPMI-12-24-0154-R","DOIUrl":"10.1094/MPMI-12-24-0154-R","url":null,"abstract":"<p><p>Potato powdery scab, caused by the soilborne pathogen <i>Spongospora subterranea</i> f. sp. <i>subterranea</i> (<i>Sss</i>), poses a significant threat to potato production, reducing potato value and impacting fresh market quality. Effective management strategies for this disease are currently lacking, and <i>Sss</i> is widespread in many potato-growing regions, highlighting the urgent need for effective control measures. Although the use of disease-resistant cultivars holds potential as a sustainable solution, the genetic mechanisms underlying resistance to <i>Sss</i> remain unclear. In this study, we investigated the role of the defense-related phytohormone salicylic acid (SA) in potato resistance to <i>Sss</i>. Initial analyses of defense gene expression revealed transcriptional reprogramming in response to <i>Sss</i> infection in potato hairy root cultures. Quantification of defense-related phytohormones further demonstrated a significant increase in SA levels in <i>Sss</i>-infected roots, whereas other phytohormones, jasmonic acid and ethylene, showed no substantial variation. Pretreatment of hairy roots with SA resulted in a marked reduction in <i>Sss</i> propagation, suggesting that SA contributes to induced resistance against the pathogen. To further elucidate the role of SA, we utilized transgenic potato hairy roots overexpressing the tomato SA receptor gene <i>SlNPR1</i> to enhance SA sensitivity or expressing the bacterial <i>nahG</i> gene to deplete endogenous SA. Our findings showed reduced <i>Sss</i> growth in <i>SlNPR1</i> overexpression lines, whereas <i>nahG</i> lines exhibited increased pathogen proliferation. These findings were further validated in fully grown potato plants using a pot assay. Collectively, our results indicate that SA plays a pivotal role in mediating resistance to powdery scab in potato. [Formula: see text] Copyright © 2025 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.</p>","PeriodicalId":19009,"journal":{"name":"Molecular Plant-microbe Interactions","volume":" ","pages":"599-609"},"PeriodicalIF":3.4,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143468639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The <i>Alternaria alternata</i> Mip1/RAPTOR Mediates Virulence by Regulating Toxin Production and Autophagy.","authors":"Yu-Ling Huang, Kuang-Ren Chung, Pei-Ching Wu","doi":"10.1094/MPMI-12-24-0161-R","DOIUrl":"10.1094/MPMI-12-24-0161-R","url":null,"abstract":"<p><p>The necrotrophic pathogen <i>Alternaria alternata</i> produces a host-selective toxin to attack its host plants. This study characterized the crucial function of the Mip1/RAPTOR ortholog (AaMip1) in toxin production and autophagy formation. AaMip1 physically interacts with the Target of Rapamycin (Tor) protein. In response to nitrogen starvation and hydrogen peroxide (H₂O₂), AaMip1 binds to Tor and triggers autophagy and oxidative stress detoxification. Deleting the <i>AaMip1</i> gene resulted in a Δ<i>AaMip1</i> strain that increased sensitivity to various oxidants; decreased the expression of two oxidative-stress-response genes, <i>AaYap1</i> and <i>AaNoxA</i>; and had lower catalase activity than the wild type. Δ<i>AaMip1</i> produced lower levels of ACT toxin than the wild type after a 7-day incubation; however, Δ<i>AaMip1</i> produced tricycloalternarene mycotoxins but not ACT after 21 days. The reduction of Δ<i>AaMip1</i> virulence in the host plant is due to low ACT production, defective H₂O₂ detoxification, impaired autophagy, and slow growth during invasion. However, AaMip1 plays a negative role in maintaining cell wall integrity and lipid body accumulation. Δ<i>AaMip1</i> had thicker cell walls and emitted brighter red fluorescence after staining with the cell-wall-disrupting agents Congo red and calcofluor white. Δ<i>AaMip1</i> was more resistant to these compounds than the wild type under nutrient-rich conditions. The observed defects in the Δ<i>AaMip1</i> were restored in the complementation strain after re-expressing a functional copy of <i>AaMip1</i>. This study increases our understanding of how <i>A. alternata</i> deals with toxic reactive oxygen species, triggers autophagy formation, maintains normal cell wall integrity, and regulates toxin metabolism via the AaMip1-mediated signaling pathways. [Formula: see text] Copyright © 2025 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.</p>","PeriodicalId":19009,"journal":{"name":"Molecular Plant-microbe Interactions","volume":" ","pages":"610-622"},"PeriodicalIF":3.4,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143584904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Suppression of a Transketolase Mutation Leads to Only Partial Restoration of Symbiosis in <i>Sinorhizobium meliloti</i>.","authors":"Sabhjeet Kaur, Justin P Hawkins, Ivan J Oresnik","doi":"10.1094/MPMI-02-25-0017-R","DOIUrl":"10.1094/MPMI-02-25-0017-R","url":null,"abstract":"<p><p>The interaction between <i>Sinorhizobium meliloti</i> and alfalfa is a well-studied model system for symbiotic establishment between rhizobia and legume plants. Proper utilization of carbon sources has been linked with effective symbiotic establishment in <i>S. meliloti</i> strain Rm1021. Previous work has shown that mutation of the gene <i>tktA</i>, which encodes a transketolase involved in the pentose phosphate pathway, resulted in a strain impaired in many biological functions, including the ability to establish symbiosis with alfalfa. Work with this strain revealed the appearance of suppressor mutations that could partially revert the symbiotic phenotype associated with a <i>tktA</i> mutation. Characterization of these suppressor strains showed that carbon phenotypes associated with a mutation in <i>tktA</i> were no longer present and that the production of succinoglycan was partially restored. Central carbon metabolite pools were observed to be different compared with the wild-type and <i>tktA</i> mutant strains. Multiple independent mutations were identified in the gene <i>SMc02340</i>, a Gnt-type negative regulator, upon sequencing. RT-PCR suggested that <i>SMc02340</i> acts as a negative regulator on an operon containing the gene <i>tktB</i>, which becomes upregulated when the suppressor mutation is present or <i>SMc02340</i> is removed. Microscopic analysis revealed a unique symbiotic phenotype. The <i>tktA</i> mutant strain induced root hair curling but could not colonize the apoplastic space. Collectively, the data suggest that the upregulation of <i>tktB</i> can partially bypass some blocks associated with a lesion in <i>tktA</i>, including the colonization of the curled root hair, but cannot fully compensate for the loss of <i>tktA</i>. [Formula: see text] Copyright © 2025 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.</p>","PeriodicalId":19009,"journal":{"name":"Molecular Plant-microbe Interactions","volume":" ","pages":"505-517"},"PeriodicalIF":3.4,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143586344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"<i>Xanthomonas oryzae</i> pv. <i>oryzae</i> Type III Effector Tal9b Targets a Broadly Conserved Disease Susceptibility Locus to Promote Pathogenesis in Rice.","authors":"Gokulan C G, Sohini Deb, Namami Gaur, Apoorva Masade, Niranjan Gattu, Rennya P R, Nisha Sao, Donald James, Ramesh V Sonti, Hitendra K Patel","doi":"10.1094/MPMI-10-24-0139-R","DOIUrl":"10.1094/MPMI-10-24-0139-R","url":null,"abstract":"<p><p><i>Xanthomonas oryzae</i> pv. <i>oryzae</i> (<i>Xoo</i>), the causal agent of bacterial blight of rice, translocates multiple transcription activator-like effectors (TALEs) into rice cells. The TALEs localize to the host cell nucleus, where they bind to the DNA in a sequence-specific manner and enhance gene expression to promote disease susceptibility. <i>Xoo</i> strain PXO99^A encodes 19 TALEs, but the host targets of all these TALEs have not been defined. A meta-analysis of rice transcriptome profiles revealed a gene annotated as flavonol synthase/flavanone-3 hydroxylase (henceforth <i>OsS5H/FNS-03g</i>) to be highly induced upon <i>Xoo</i> infection. Further analyses revealed that this gene is induced by PXO99^A using Tal9b, a broadly conserved TALE of <i>Xoo</i>. Disruption of <i>tal9b</i> rendered PXO99^A less virulent. OsS5H/FNS-03g functionally complemented its <i>Arabidopsis</i> homologue AtDMR6, a well-studied disease susceptibility locus. Biochemical analyses suggested that OsS5H/FNS-03g is a bifunctional protein with salicylic acid 5' hydroxylase (S5H) and flavone synthase-I (FNS-I) activities. Further, an exogenous application of apigenin, the flavone that is enzymatically produced by OsS5H/FNS-03g, on rice leaves promoted virulence of PXO99^A <i>tal9b^-</i>. Overall, our study suggests that OsS5H/FNS-03g is a bifunctional enzyme, and its product, apigenin, is potentially involved in promoting <i>Xoo</i> virulence. [Formula: see text] Copyright © 2025 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.</p>","PeriodicalId":19009,"journal":{"name":"Molecular Plant-microbe Interactions","volume":" ","pages":"579-588"},"PeriodicalIF":3.4,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144008653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Differential Effects of Local dsRNA Application on Systemic Beet Mosaic Virus Resistance in <i>Nicotiana benthamiana</i> and <i>Beta vulgaris</i>.","authors":"Dennis Rahenbrock, Marieke Bode, Mark Varrelmann","doi":"10.1094/MPMI-01-25-0009-R","DOIUrl":"10.1094/MPMI-01-25-0009-R","url":null,"abstract":"<p><p>Beet mosaic virus (BtMV) is one of several viruses infecting sugar beets and was previously managed by controlling the vector <i>Myzus persicae</i> with neonicotinoid seed treatment. Following the ban of this measure in 2019 in Europe, alternative control strategies needed to be researched. One alternative might be the use of RNA interference as a major antiviral defense system. Here, we report the selection of target regions using small RNA high-throughput sequencing of BtMV-infected <i>Beta vulgaris</i> subsp. <i>vulgaris</i> and <i>Nicotiana benthamiana</i> plants, the production of double-stranded RNA (dsRNA), and the effective use of dsRNA in inducing resistance against the mechanically inoculated virus under greenhouse conditions. In <i>Escherichia coli</i> HT115, the dsRNAs produced for BtMV P1 and nuclear inclusion body b (NIb) induced a high level of resistance when sprayed before mechanical BtMV inoculation, resulting in an 80% reduction of symptomatic <i>B. vulgaris</i> and <i>N. benthamiana</i> plants. Stem-loop RT-qPCR showed the systemic distribution of dsRNA-derived small interfering RNA molecules, but the applied dsRNA remained at the site of application and did not spread within the plant. However, when the virus was inoculated on the next upward leaf to the dsRNA application site, no protective effect was observed. Despite this limitation, the results demonstrate the potential of dsRNA as an effective tool for viral protection in sugar beets, thereby establishing a basis for future developments in systemic delivery and broader field applications. [Formula: see text] Copyright © 2025 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.</p>","PeriodicalId":19009,"journal":{"name":"Molecular Plant-microbe Interactions","volume":" ","pages":"518-528"},"PeriodicalIF":3.4,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143795710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CRISPR/Cas9-Mediated Disruption of <i>CsLIEXP1</i> Reveals Expansin as a Key Susceptibility Factor for Citrus Canker Disease.","authors":"Reinaldo Rodrigues de Souza-Neto, Lídia Nascimento Cavalcante, Isis Gabriela Barbosa Carvalho, Maiara Curtolo, Celso Eduardo Benedetti, Marco Aurélio Takita, Nian Wang, Alessandra Alves de Souza","doi":"10.1094/MPMI-12-24-0151-R","DOIUrl":"10.1094/MPMI-12-24-0151-R","url":null,"abstract":"<p><p>The <i>Citrus sinensis LATERAL ORGAN BOUNDERIES 1</i> (<i>CsLOB1</i>) gene, which is directly induced by the <i>Xanthomonas citri</i> subsp. <i>citri</i> effector PthA4, functions as a transcription factor and citrus canker susceptibility (S) gene. Genome editing of <i>CsLOB1</i> has been shown to confer resistance to citrus canker disease. Previous studies revealed that the citrus <i>CsLOB1-INDUCED EXPANSIN 1</i> gene (<i>CsLIEXP1</i>) is highly and directly upregulated by <i>CsLOB1</i> in <i>Xanthomonas citri</i> subsp. <i>citri</i>-infected plants. Because expansins are associated with cell wall loosening, potentially facilitating bacterial colonization, the <i>CsLOB1-</i>dependent activation of <i>CsLIEXP1</i> is thought to contribute to canker symptoms and disease progression. Thus, <i>CsLIEXP1</i> likely represents a critical canker susceptibility gene. In this study, we employed CRISPR/Cas9 to disrupt the function of <i>CsLIEXP1</i> by modifying its corresponding coding region in <i>Citrus sinensis</i> cultivar 'Hamlin' and evaluated the postinfection responses of edited plants. DNA sequencing confirmed the edition of the <i>CsLIEXP1</i>-edited plant, which exhibited 26.47% of <i>CsLIEXP1</i> edited sequences. Furthermore, <i>CsLIEXP1</i> protein accumulation was reduced in <i>CsLIEXP1</i>-edited plants compared with the wild type when infected with <i>X. citri</i>. Leaves of edited plants inoculated with <i>X. citri</i> showed significantly fewer canker symptoms, with lesions limited to the site of bacterial inoculation and less pronounced cellular hypertrophy compared with control plants. Our results show that <i>CsLIEXP1</i> is a citrus canker S gene that acts downstream of <i>CsLOB1</i>, thus providing new insights into plant-pathogen interactions. [Formula: see text] Copyright © 2025 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.</p>","PeriodicalId":19009,"journal":{"name":"Molecular Plant-microbe Interactions","volume":" ","pages":"589-598"},"PeriodicalIF":3.4,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143772410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pleiotropic Phenotypes of the Tomato <i>diageotropica</i> Mutant Enable Resistance to <i>Ralstonia solanacearum</i>.","authors":"Katherine Rivera-Zuluaga, Pratibha Choudhary, Sana Mohammad, Denise Caldwell, Rebecca Leuschen-Kohl, Pete E Pascuzzi, Anjali Iyer-Pascuzzi","doi":"10.1094/MPMI-10-24-0123-R","DOIUrl":"10.1094/MPMI-10-24-0123-R","url":null,"abstract":"<p><p>Quantitative disease resistance (QDR) is the most common form of disease resistance in crops, but it is challenging to understand at the cellular level due to the involvement of many genes and biological processes. <i>Ralstonia solanacearum</i>, the causal agent of bacterial wilt disease, is a destructive plant pathogen of Solanaceous species that is best controlled by quantitatively resistant varieties, but few QDR genes are known. We previously found that a tomato auxin pathway mutant known as <i>diageotropica</i> (<i>dgt</i>) has enhanced resistance to <i>R. solanacearum</i>. Here, we show that, as with wild-type quantitatively resistant tomato plants, resistance in <i>dgt</i> is the result of multiple mechanisms. Mock-inoculated <i>dgt</i> roots have endogenously higher levels of the plant defense hormone salicylic acid (SA). However, the SA-deficient double mutant <i>dgtNahG</i> is still resistant to <i>R. solanacearum</i>, indicating that SA-independent pathways are also required for resistance. Scanning electron microscopy revealed that <i>R. solanacearum</i> colonization of the root xylem is delayed in <i>dgt</i>. We found an increased number of lignified xylem cells and altered root vasculature anatomy in <i>dgt</i>, and <i>dgt</i> root length was not impacted by <i>R. solanacearum</i> treatment. Similar to the wilt-resistant wild-type tomato Hawaii7996, RNA sequencing results suggested that <i>dgt</i> may tolerate <i>R. solanacearum</i>-induced water stress better than the wilt-susceptible parent. Thus, resistance in <i>dgt</i> is due to several pathways, including preactivated SA defenses, physical barriers in the xylem, and an ability to tolerate water stress. The pleiotropic nature of this single mutation appears to mimic quantitative resistance. [Formula: see text] Copyright © 2025 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.</p>","PeriodicalId":19009,"journal":{"name":"Molecular Plant-microbe Interactions","volume":" ","pages":"566-578"},"PeriodicalIF":3.4,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144019093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Soilborne Fungus <i>Verticillium longisporum</i> and Its Interactions with the Brassicaceous Hosts.","authors":"Vahideh Rafiei, Christina Dixelius, Georgios Tzelepis","doi":"10.1094/MPMI-03-25-0029-IRW","DOIUrl":"10.1094/MPMI-03-25-0029-IRW","url":null,"abstract":"<p><p><i>Verticillium longisporum</i>, a soilborne fungal species, is the causative agent of Verticillium stripe disease in <i>Brassica</i> species and represents a notable threat to agricultural production, particularly in regions where oilseed rape is a major crop, including Europe, North America, and Asia. The microsclerotia of this pathogen can persist in the soil for extended periods, with a potential lifespan of up to a decade, thereby posing a substantial challenge for the complete eradication of the pathogen from infested soil. The genome of <i>V. longisporum</i> is amphidiploid and resulted from the hybridization of <i>V. dahliae</i> (D genotypes) and an unidentified species (A1 genotype). At least three independent hybridization events are estimated to have occurred, resulting in three distinct lineages: A1/D1, A1/D2, and A1/D3. Genome sequence analysis revealed the presence of mating-type idiomorphs, putative cell wall-degrading enzymes, and effectors. However, due to the complexity of the genome, there is a paucity of research on the molecular interactions between <i>V. longisporum</i> and <i>Brassica</i> crops. This review summarizes the extant knowledge regarding the pathogenicity factors that <i>V. longisporum</i> deploys upon infection and the host immune responses against this attack, highlighting aspects that remain to be elucidated and the molecular tools available for studying this interaction. A better understanding of the molecular interactions in this pathosystem will contribute to developing more effective control measures against this disease in <i>Brassica</i> oilseed and cabbage crops. [Formula: see text] Copyright © 2025 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.</p>","PeriodicalId":19009,"journal":{"name":"Molecular Plant-microbe Interactions","volume":" ","pages":"497-504"},"PeriodicalIF":3.4,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143990769","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Non-Nitrogen-Fixing <i>Sinorhizobium meliloti</i> Can Escape Sanctions in Indeterminate Alfalfa Nodules, Exhibiting Parasitic Growth.","authors":"Amanpreet K Brar, Katherine M Bilodeau, Darryl J Trickey, Calvin S Mackey, Bryce L Redfern, Gabrielle T Fisher, Ellen L Simms, Kathryn M Jones","doi":"10.1094/MPMI-06-25-0074-R","DOIUrl":"https://doi.org/10.1094/MPMI-06-25-0074-R","url":null,"abstract":"<p><p>The soil bacterium <i>Sinorhizobium meliloti</i> can proliferate by leveraging its nitrogen-fixing symbiosis with legumes that form indeterminate root nodules, such as <i>Medicago sativa</i> (alfalfa) and <i>M. truncatula</i>. In contrast to determinate-nodulating legumes, e.g. <i>Glycine max</i> (soybean) and <i>Lotus japonicus</i>, indeterminate-nodulating legumes impose terminal differentiation on nitrogen-fixing (N₂-fixing) rhizobia. Thus, the bacterial population is split between those that benefit the plant by N₂ fixation, but are a reproductive dead end, and those that are undifferentiated, capable of resuming free-living growth, but not fixing nitrogen. We show that, in mixed nodules colonized by nearly-isogenic strains, with one N₂-fixing and one unable to fix N₂ (Fix-), alfalfa do not preferentially penalize the Fix- strain, allowing 'cheating' at the expense of the plant and the N₂-fixer. Thus, a Fix- strain that successfully co-nodulates with a N₂-fixing strain can benefit from resources the host provides to the nodule in response to N₂ fixed by the co-nodulating strain. Co-invasion of alfalfa nodules with a N₂-fixing strain may be a successful strategy for a Fix- strain to cheat both the plant that provides fixed carbon and the N₂-fixing strain.</p>","PeriodicalId":19009,"journal":{"name":"Molecular Plant-microbe Interactions","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144485181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Population Genomics of <i>Macrophomina</i> spp. Reveals Cryptic Host Specialization and Evidence for Meiotic Recombination.","authors":"K K Pennerman, P Goldman, C J Dilla-Ermita, G Ramos, J H Jaime, J Lopez-Hernandez, J Ramos, M Aviles, C Borrero, A O Gomez, J M Neal, M Chilvers, V Ortiz, E H Stukenbrock, G H Goldman, A Mengistu, H D Lopez-Nicora, G O Sacher, N Vaghefi, L Kiss, J P Benz, A R Machado, T E Seijo, N A Peres, F N Martin, J C Broome, K Ivors, G S Cole, S J Knapp, D J McFarlane, S W Mattner, M Gambardella, E Gluck-Thaler, P M Henry","doi":"10.1094/MPMI-03-25-0032-R","DOIUrl":"https://doi.org/10.1094/MPMI-03-25-0032-R","url":null,"abstract":"<p><p>Knowledge of the factors structuring populations of pathogenic fungi is fundamental to disease management efforts and basic biology. However, this crucial information is missing for many important pathogens, including broad host range and drought-associated pathogens from the globally distributed <i>Macrophomina</i> genus. The objectives of this work were to evaluate the evidence for host specialization, geographic adaptation, and recombination using a global survey of <i>Macrophomina</i> isolates from diverse geographic, temporal, and host sources. We obtained high-quality short-read sequence data for 463 <i>Macrophomina</i> spp. isolates, representing four putative species, collected from 91 host plant species and soil in 23 countries. Analysis of bi-allelic, single nucleotide polymorphismsrevealed high diversity, admixture, and equal mating type ratios suggesting on-going recombination. Although most tested isolates asymptomatically colonized strawberry, only strawberry-derived isolates caused disease on this host. These isolates were all in a single lineage, suggesting the ability to cause disease on strawberry is not widespread among <i>M. phaseolina</i>. Significant associations were also found between isolation from soybean plants and specific population clusters, suggesting that specialization for virulence or reproduction has also occurred for soybean. Geography × isolate genotype associations were weak, suggesting <i>Macrophomina</i> spp. were frequently trafficked between regions. Reference free whole genome comparisons support current boundaries among four <i>Macrophomina</i> species, and new molecular markers were designed to specifically identify each species. Contrary to expectations, <i>M. phaseolina</i> should be considered a single species with both specialist and generalist populations in which meiosis can maintain genetic diversity.</p>","PeriodicalId":19009,"journal":{"name":"Molecular Plant-microbe Interactions","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144485182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}