Phytopathology最新文献

{"title":"Opportunities and Challenges in Combining Optical Sensing and Epidemiological Modelling.","authors":"Alexey Mikaberidze, C D Cruz, Ayalsew Zerihun, Abel Barreto, Pieter Beck, Rocío Calderón, Carlos Camino, Rebecca E Campbell, Stephanie K L Delalieux, Frederic Fabre, Elin Falla, Stuart Fraser, Kaitlin M Gold, Carlos Gongora-Canul, Frédéric Hamelin, Dalphy O C Harteveld, Cheng-Fang Hong, Melen Leclerc, Da-Young Lee, Murillo Lobo, Anne-Katrin Mahlein, Emily McLay, Paul Melloy, Stephen Parnell, Uwe Rascher, Jack Rich, Irene Salotti, Samuel Soubeyrand, Susan Sprague, Antony Surano, Sandhya D Takooree, Thomas H Taylor, Suzanne Touzeau, Pablo J Zarco-Tejada, Nik J Cunniffe","doi":"10.1094/PHYTO-11-24-0359-FI","DOIUrl":"https://doi.org/10.1094/PHYTO-11-24-0359-FI","url":null,"abstract":"<p><p>Plant diseases impair yield and quality of crops and threaten the health of natural plant communities. Epidemiological models can predict disease and inform management. However, data are scarce, since traditional methods to measure plant diseases are resource intensive and this often limits model performance. Optical sensing offers a methodology to acquire detailed data on plant diseases across various spatial and temporal scales. Key technologies include multispectral, hyperspectral and thermal imaging, and light detection and ranging; the associated sensors can be installed on ground-based platforms, uncrewed aerial vehicles, aeroplanes and satellites. However, despite enormous potential for synergy, optical sensing and epidemiological modelling have rarely been integrated. To address this gap, we first review the state-of-the-art to develop a common language accessible to both research communities. We then explore the opportunities and challenges in combining optical sensing with epidemiological modelling. We discuss how optical sensing can inform epidemiological modelling by improving model selection and parameterisation and providing accurate maps of host plants. Epidemiological modelling can inform optical sensing by boosting measurement accuracy, improving data interpretation and optimising sensor deployment. We consider outstanding challenges in: A) identifying particular diseases; B) data availability, quality and resolution, C) linking optical sensing and epidemiological modelling, and D) emerging diseases. We conclude with recommendations to motivate and shape research and practice in both fields. Among other suggestions, we propose to standardise methods and protocols for optical sensing of plant health and develop open access databases including both optical sensing data and epidemiological models to foster cross-disciplinary work.</p>","PeriodicalId":20410,"journal":{"name":"Phytopathology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144174664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An Unconventionally Secreted Effector VmUSP1 Targets Apple Heat Shock Protein 70 to Promote Infection.","authors":"Chengli Wang, Tao Jiang, Meilian Li, Yonghui Lin, Ming Xu, Xuejing Wen, Daoyuan Zhang, Lili Huang","doi":"10.1094/PHYTO-12-24-0417-R","DOIUrl":"https://doi.org/10.1094/PHYTO-12-24-0417-R","url":null,"abstract":"<p><p>Apple Valsa Canker (AVC), caused by <i>Valsa mali</i>/<i>Cytospora mali</i>, is a highly destructive disease that leads to significant economic losses annually. Pathogens manipulate host immunity to facilitate colonization and infection through the secretion of effector proteins, which are typically identified based on the presence of signal peptides. However, unconventional secretory effector proteins have been neglected, and little is known about their protogenetic roles in virulence. In this study, we demonstrate that an unconventional secreted protein 1 (VmUSP1) not only inhibits BAX and INF1-induced cell death but also plays a crucial role in the complete virulence of <i>V. mali</i>. Furthermore, VmUSP1 lacks a typical signal peptide and exhibits characteristics of unconventional secretion. Through yeast two-hybrid (Y2H), bimolecular fluorescence (BiFC), and co-immunoprecipitation (Co-IP) assays, we confirmed that VmUSP1 targets an apple (<i>Malus</i> × <i>domestica</i>) heat shock protein 70 (MdHSP70). MdHSP70 induces the accumulation of reactive oxygen species and callose, while significantly enhancing plant resistance against pathogens. Additionally, VmUSP1 greatly compromises the MdHSP70-mediated resistance of apple against <i>V. mali</i>. Overall, these findings elucidate a mechanism by which an unconventionally secreted effector from <i>V. mali</i> suppresses host resistance by interfering with MdHSP70-mediated immune responses.</p>","PeriodicalId":20410,"journal":{"name":"Phytopathology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144161485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The PDZ Domain-Containing Protein Prc Is Involved in Virulence and Stress Tolerance in the Poplar Canker Bacterium <i>Lonsdalea populi</i>.","authors":"Zexu Ming, Ruirui Yang, Sha Zeng, Aining Li","doi":"10.1094/PHYTO-02-25-0066-R","DOIUrl":"https://doi.org/10.1094/PHYTO-02-25-0066-R","url":null,"abstract":"<p><p>Proteins harboring the PDZ domain are of utmost significance in the infection course of pathogenic bacteria as well as in the response to external environmental stresses. In this study, we demonstrated that the <i>Lonsdalea populi</i> genome encodes a set of five proteins with the PDZ domain. Through a systematic inactivation of the genes responsible for encoding PDZ proteins, we showed that all these genes are closely related to the virulence of <i>L. populi</i>. Notably, deletion of <i>prc</i> results in suppression of the growth of <i>L. populi</i> and enhanced susceptibility to a diverse array of environmental stressors such as hydrogen peroxide (H₂O₂), chloramphenicol, spectinomycin, and metal ions such as Mn²⁺, Fe²⁺ and Fe³⁺. Since Prc contains four domains including TSPn, PDZ, PEP, and DUF, after separately knocking out the four domains within Prc, we have demonstrated that the TSPn, PDZ, and PEP domains within Prc are all essential components in the pathogenic process of <i>L. populi</i>. Moreover, Prc interacts with the membrane protein YccA. This interaction regulates the biofilm formation capacity and motility of <i>L. populi</i>, thus exerting an impact on its virulence. Together, these findings suggest that Prc is an important regulator of virulence and stress response in <i>L. populi</i>.</p>","PeriodicalId":20410,"journal":{"name":"Phytopathology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144161409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Population Genomic Analysis of Two Independent Clonal Invasions of the Sudden Oak Death Pathogen into One Forest.","authors":"Nicholas C Cauldron, Hazel A Daniels, Jared M LeBoldus, Niklaus J Grünwald","doi":"10.1094/PHYTO-10-24-0329-FI","DOIUrl":"https://doi.org/10.1094/PHYTO-10-24-0329-FI","url":null,"abstract":"<p><p>Upon introduction, clonal pathogen populations are expected to go through a genetic bottleneck followed by gradual clonal divergence. Two distinct and purely clonal lineages of the sudden oak death pathogen <i>Phytophthora ramorum</i> recently emerged in forests in the Western United States, providing the unique opportunity to study a naturally replicated invasion into the same ecosystem. We characterized population genomic patterns during early invasion using whole genome sequencing of two <i>P. ramorum</i> clonal lineages sampled in the first five years following their detection. We re-sequenced genomes from populations of two dominant clonal lineages, NA1 (n=134; 2001-2005) and EU1 (n=160; 2015-2019), and obtained 106,070 high-quality SNPs in genic regions. Our results are consistent with the hypothesis of one introduction for each lineage. The NA1 population had a wider distribution of pairwise genetic distances than EU1 and higher genetic diversity, though neither NA1 nor EU1 populations clustered clearly by year. There was significant correlation between genetic distance and geographic distance for NA1 (<i>p</i> = 0.042), but not for EU1 (<i>p</i> = 0.402). The genetic diversity in NA1 is strongly driven by loss of heterozygous positions, which impacted more than one-third of the sampled NA1 population. However, loss of heterozygosity was rare in EU1. This work provides novel insights into the invasion biology and dynamics of clonal plant pathogens in natural ecosystems.</p>","PeriodicalId":20410,"journal":{"name":"Phytopathology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144161503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Soil Temperature and Moisture Conditions Affect the Recovery and Sporulation Capacity of <i>Phytophthora ramorum</i> from Infested <i>Rhododendron</i> Leaf Disks.","authors":"Ebba K Peterson, Niklaus J Grünwald, Jennifer L Parke","doi":"10.1094/PHYTO-02-25-0056-R","DOIUrl":"https://doi.org/10.1094/PHYTO-02-25-0056-R","url":null,"abstract":"<p><p>The invasive pathogen <i>Phytophthora ramorum</i> persists within nurseries, potentially within buried, infested leaf debris. To determine how the environment - notably soil temperature and moisture levels - affects the epidemiological risk of soil inoculum reserves, we performed laboratory assays assessing how variable conditions impact pathogen survival and its capacity to sporulate. We first established that incubating inoculum at 4°C increases the number of sporangia produced from infested rhododendron leaf disks. In a second experiment, inoculum was incubated in soil at a range of temperature (6.7, 14, 20, or 28°C) and soil moisture (approximating 0, -40, or -400 kPa) conditions for up to 18 weeks. Our ability to culture <i>P. ramorum</i> was only negatively affected by the warmest and driest regimes. In contrast, the capacity to sporulate was affected over a much wider range of conditions, whereby declines in sporulation potential were observed over time from inoculum incubated at both 20 and 28°C in all soil moisture conditions. However, subsequent incubation of this inoculum at 4°C for an additional seven weeks restored sporulation potential, at times exceeding pre-incubation levels. These results are consistent with field-observations that <i>P. ramorum</i> becomes more biologically active after exposure to cooler temperatures, and highlights the risk soilborne inoculum poses during some times of the year. Disinfestation of soils through artificially high heat is likely required to prevent recurrent infections within nurseries from soilborne sources, and thus prevent the further spread of this invasive pathogen.</p>","PeriodicalId":20410,"journal":{"name":"Phytopathology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144161408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Emerging <i>Xanthomonas prunicola</i> Strains Cause Bacterial Leaf Necrosis of Wheat.","authors":"Felipe Clavijo, Veronica Roman-Reyna, Rebecca D Curland, Ruth Dill-Macky, Jonathan M Jacobs, Carolina Leoni, Lucía Coimbra, Silvia Pereyra, María I Siri","doi":"10.1094/PHYTO-02-25-0044-R","DOIUrl":"https://doi.org/10.1094/PHYTO-02-25-0044-R","url":null,"abstract":"<p><p><i>Xanthomonas prunicola</i>, initially described as a nectarine pathogen, has emerged as the causal agent of a new wheat disease, <i>Bacterial Leaf Necrosis</i> (BLN). This study compares <i>X. prunicola</i> strains isolated from wheat fields in Uruguay and the United States to nectarine-associated strains using genomic and pathogenicity analyses to identify factors driving host specificity. Pathogenicity assays revealed clear differences between the two groups: while <i>X. prunicola</i> wheat-associated strains caused distinct dry necrosis lesions in wheat; the reference strain isolated from nectarine failed to induce any symptoms in this host. Surprisingly, most of the wheat strains elicited water-soaking symptoms in <i>Prunus persica</i>, similar to those caused by the <i>X. prunicola</i> strain isolated from nectarine. Complete high-quality genomes were obtained for the six selected <i>X. prunicola</i> strains. Genomic analyses confirmed their identification and revealed that wheat-associated strains form a distinct phylogenomic cluster separated from nectarine-associated strains. Comparative analyses identified key differences, including a functional Type VI Secretion System (T6SS), absent in nectarine strains, and unique Type III effectors, XopR and XopW, potentially linked to wheat pathogenicity. These findings underscore the importance of understanding the epidemiology of this emerging pathogen, transmission pathways, and host specificity to mitigate its impact on wheat production and develop targeted control strategies.</p>","PeriodicalId":20410,"journal":{"name":"Phytopathology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144174663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization of Mycotoxin and Furanoterpenoid Production by Fusarium Species Infecting Sweetpotato.","authors":"U Bhatta, J R Standish, O Baars, L M Quesada-Ocampo","doi":"10.1094/PHYTO-01-25-0031-R","DOIUrl":"https://doi.org/10.1094/PHYTO-01-25-0031-R","url":null,"abstract":"<p><p>Sweetpotato (<i>Ipomoea batatas</i>) production is threatened by Fusarium root rot, which can lead to substantial yield losses and contamination with mycotoxins and phytotoxins. This study investigated the production of mycotoxins by different <i>Fusarium</i> species and isolates in vitro and in vivo, as well as furanoterpenoid compounds produced by sweetpotato in response to <i>Fusarium</i> infection and wounding. Among 37 <i>Fusarium</i> isolates tested, only four <i>Fusarium proliferatum</i> isolates (AS050, AS116, JS603 and NM229) produced significant levels of fumonisins B1 and B2 in sweetpotato roots, with NM229 exhibiting the highest mycotoxin concentrations. Notably, fumonisin production differed between in vivo and in vitro conditions. In sweetpotato roots, fumonisin concentrations for NM229 decreased over time, while in liquid culture, concentrations increased. The other isolates produced minimal amounts of fumonisins, with no significant changes over time in either condition. An untargeted metabolomics analysis showed several putative furanoterpenoids, both wounding-induced and <i>Fusarium</i>-specific. Wounding alone triggered production of certain furanoterpenoids, while <i>Fusarium</i> infections, particularly <i>F. denticulatum</i> infections resulted in the highest levels of phytotoxins, including ipomeamarone, 4-hydroxymyoporone, 1-ipomeanol, and 4-ipomeanol. <i>Fusarium acuminatum</i>, <i>F. commune</i>, and <i>F. proliferatum</i> isolates induced some additional putative furanoterpenoids based on observed similar fragmentation patterns. These findings highlight the complex interaction between mechanical damage and <i>Fusarium</i> infection in stimulating phytotoxin production in sweetpotato and emphasize the importance of effective disease management strategies. The detection of high fumonisin levels, exceeding FDA guidelines for human food (2-4 ppm), underscores the need for monitoring and controlling <i>Fusarium</i> infections in sweetpotato production.</p>","PeriodicalId":20410,"journal":{"name":"Phytopathology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144161496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrative Elements Repeatedly Captured the Phaseolotoxin Biosynthesis Gene Cluster and Invaded <i>Pseudomonas syringae</i> Multiple Times.","authors":"Luiz Orlando de Oliveira, Hugo Vianna Silva Rody, Selene Aguilera, Jesus Murillo","doi":"10.1094/PHYTO-01-25-0017-R","DOIUrl":"https://doi.org/10.1094/PHYTO-01-25-0017-R","url":null,"abstract":"<p><p>Phaseolotoxin is a virulence factor of <i>Pseudomonas amygdali</i> pv. <i>phaseolicola</i> (Pph) and <i>P. syringae</i> pv. <i>actinidiae</i> (Psa). Herein, we explore the evolutionary history of a genomic island (Tox island) composed of an integrative element (GInt) carrying the 23-gene cluster (Pht cluster) for biosynthesis of phaseolotoxin and toxin resistance. Our analyses indicate that the Pht cluster has been acquired, either naked or associated with a GInt, on seven independent occasions by four phylogroups of the <i>P. syringae</i> complex (Pph, Psa, <i>P. caricapapayae</i>, and <i>P. syringae</i> pv. <i>syringae</i>) and the phylogenetically distant rhizobacterium <i>Pseudomonas</i> sp. JAI115. The Pht cluster was independently captured by three distinct GInt elements, suggesting specific mechanisms for gene capture. Once acquired, the Tox island tends to be stably maintained, evolving with the genome. The likely evolutionary trajectory of the Tox island within Pph and Psa involved: i) acquisition by Pph; ii) transfer of the Tox island from Pph to Psa biovar 1; iii) independent acquisition from unknown sources of a different version of the Tox island by Psa biovar 1, generating a second toxigenic lineage; 4) independent acquisition from unknown sources of a third version of the Tox island by Psa biovar 6; and 5) replacement of the Tox island in Pph by a distantly related GInt, generating nontoxigenic isolates. These findings underscore the potential role of phaseolotoxin in bacterial fitness and contribute to our understanding of the evolutionary dynamics of mobile genetic elements and virulence evolution in bacterial plant pathogens.</p>","PeriodicalId":20410,"journal":{"name":"Phytopathology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144161497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Role of Organic Amendment Composition and Soil Texture in Modulating Volatile Fatty Acids, Fe/Mn Reduction, and <i>Fusarium oxysporum</i> Suppression During Anaerobic Soil Disinfestation in Neutral to Alkaline Soils.","authors":"James Littrell, Bonnie H Ownley, Zachariah R Hansen, Kimberly D Gwinn, David M Butler","doi":"10.1094/PHYTO-12-24-0423-R","DOIUrl":"https://doi.org/10.1094/PHYTO-12-24-0423-R","url":null,"abstract":"<p><p>Less hazardous alternatives to soil fumigants for suppressing soilborne pathogens such as pathogenic isolates within the <i>Fusarium oxysporum</i> (<i>Fo</i>) species complex that cause black root rot of strawberry are urgently needed. A promising alternative is anaerobic soil disinfestation (ASD), in which anaerobic fermentation is induced in soil, leading to production of pathogen-suppressing reduced metal cations (Fe²⁺, Mn²⁺) and volatile fatty acids (VFAs) before planting. However, little is known about how interactions between amendment composition, soil texture, and neutral to alkaline soil pH influences <i>Fo</i> suppression via soil biogeochemistry. Suppression of <i>Fo</i> was investigated in soil-based ASD incubation mesocosm trials where <i>Fo</i>-inoculated soils with initial neutral pH (sand, sandy loam, and silty clay) were amended with lime (0.1% CaCO₃) or unamended, and amended (1% w/w) with five amendment mixtures of soybean protein isolate (SPI) and dried molasses (DM) (100/0%, 75/25%, 50/50%, 25/75% or 0/100%) for a range of protein: carbohydrate ratios (0.1:1 to 32:1), to initiate ASD treatments. Post-ASD, soil chemical properties were measured, including VFA and Fe²⁺/Mn²⁺ concentrations, and <i>Fo</i> inoculum viability was assessed. Total soil VFA and Fe²⁺/Mn²⁺ concentrations were influenced by ASD amendment composition and soil texture, with the highest VFA concentrations resulting from high protein amendments and the highest Mn²⁺ concentrations observed in sandy loam and silty clay soils. <i>Fo</i> viability was reduced in all amended treatments, but finer soil textures were associated with lower <i>Fo</i> suppression. Our results highlight the importance of soil texture and amendment composition in influencing ASD effectiveness in neutral to alkaline soils.</p>","PeriodicalId":20410,"journal":{"name":"Phytopathology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144111853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of a Minireplicon for <i>Grapevine leafroll-associated virus 1</i> and Genetic Analyses of Sequences in the 5' Non-Translated Region Required for Replication.","authors":"Arunabha Mitra, Sridhar Jarugula, Rayapeti A Naidu","doi":"10.1094/PHYTO-12-24-0380-R","DOIUrl":"https://doi.org/10.1094/PHYTO-12-24-0380-R","url":null,"abstract":"<p><p>Grapevine leafroll-associated virus 1 (GLRaV-1, genus <i>Ampelovirus</i>, family <i>Closteroviridae</i>) has a monopartite RNA genome with size varying among genetic variants between 18,731 and 18,946 nucleotides (nt) and a 5' non-translated region (5'-NTR), varying in length between 857 and 922 nt. This study was undertaken to examine the role of the 5'-NTR in GLRaV-1 replication. For this purpose, a minireplicon cDNA clone, consisting of the 5'-NTR, the replicase gene module, the green fluorescent protein (GFP) reporter gene, and the 3'-NTR, was constructed. Functionality of the minireplicon was validated by GFP fluorescence and the presence of GFP-specific mRNA transcripts by Northern blot hybridization and RT-qPCR assays in <i>Nicotiana benthamiana</i> leaves agro-coinfiltrated with silencing suppressors. The minireplicon retained functionality when its 5'-NTR was exchanged with corresponding sequences from distinct genetic variants of GLRaV-1. In contrast, the minireplicon of GLRaV-1 was non-functional when its 5'-NTR sequence was swapped with corresponding sequences from other GLRaV species. Deletion mutations in the 5'-NTR indicated that the first 32 nt at the 5'-terminus of the genome are essential for replication of the minireplicon. <i>In silico</i>-predicted secondary structure of the 5'-terminal 32-nt sequence showed two stem-loop structures and mutations that altered these secondary structures or compensatory mutations preserving the secondary structures failed to retain functionality of the minireplicon, suggesting that the nucleotide sequence, rather than any higher order secondary structures in this genomic region, is important for replication.</p>","PeriodicalId":20410,"journal":{"name":"Phytopathology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144102491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}