Seedling Disease Research Articles

Early surveillance of rice bakanae disease using deep learning and hyperspectral imaging

Bakanae disease, caused by Fusarium fujikuroi, poses a significant threat to rice production and has been observed in most rice-growing regions. The disease symptoms caused by different pathogens may vary, including elongated and weak stems, slender and yellow leaves, and dwarfism, as example. Bakanae disease is likely to cause necrosis of diseased seedlings, and it may cause a large area of infection in the field through the transmission of conidia. Therefore, early disease surveillance plays a crucial role in securing rice production. Traditional monitoring methods are both time-consuming and labor-intensive and cannot be broadly applied. In this study, a combination of hyperspectral imaging technology and deep learning algorithms were used to achieve in situ detection of rice seedlings infected with bakanae disease. Phenotypic data were obtained on the 9th, 15th, and 21st day after rice infection to explore the physiological and biochemical performance, which helps to deepen the research on the disease mechanism. Hyperspectral data were obtained over these same periods of infection, and a deep learning model, named Rice Bakanae Disease-Visual Geometry Group (RBD-VGG), was established by leveraging hyperspectral imaging technology and deep learning algorithms. Based on this model, an average accuracy of 92.2% was achieved on the 21st day of infection. It also achieved an accuracy of 79.4% as early as the 9th day. Universal characteristic wavelengths were extracted to increase the feasibility of using portable spectral equipment for field surveillance. Collectively, the model offers an efficient and non-destructive surveillance methodology for monitoring bakanae disease, thereby providing an efficient avenue for disease prevention and control.

Characterizing the Diversity of Oomycetes Associated with Diseased Cotton Seedlings in Alabama.

Many oomycete species are associated with the seedlings of crops, including upland cotton (Gossypium hirsutum L.), which leads to annual threats. The diversity of oomycete species in Alabama needs to be better understood since the last survey of oomycetes associated with cotton in Alabama was 20 years ago-before significant updates to taxonomy and improvements in identification of oomycetes using molecular tools. Our current study aimed to identify oomycetes associated with Alabama cotton seedlings, correlate diversity with soil edaphic factors, and assess virulence toward cotton seed. Thirty symptomatic cotton seedlings were collected independently from 25 fields in 2021 and 2022 2 to 4 weeks after planting. Oomycetes were isolated by plating root sections onto a semiselective medium. The internal transcribed spacer (ITS) region was sequenced to identify the resulting isolates. A seed virulence assay was conducted in vitro to verify pathogenicity, and 347 oomycete isolates were obtained representing 36 species. Northern Alabama soils had the richest oomycete communities and a greater silt and clay concentration than sandier soils in the central and southern coastal plains. Globisporangium irregulare and Phytophthora nicotianae were consistently recovered from cotton roots in both years. Globisporangium irregulare was pathogenic and recovered from all Alabama regions, whereas P. nicotianae was pathogenic but recovered primarily in areas with lower sand content in northern Alabama. Many oomycete species have not been previously reported in Alabama or the southeastern United States. Altogether, this knowledge will help facilitate effective management strategies for cotton seedling diseases caused by oomycetes in Alabama and the United States.

Insidensi dan Keparahan Penyakit Bercak Daun Disebabkan oleh Curvularia sp. pada Pembibitan Kelapa Sawit di Kabupaten Banyuasin Sumatera Selatan

In Indonesia, there has been a notable expansion in the area and productivity of oil palm plantations. Oil palm is among the top seven plantation commodities prioritized for development. High-quality seedlings are essential for optimal plant production. However, several factors can impede oil palm productivity, including diseases that affect oil palm seedlings. One such disease is brown spot disease caused by the fungus Curvularia sp. The objective of this study was to determine the incidence and severity of brown spot disease in oil palm seedlings. The research was conducted from May 2023 to June 2023 in Banyuasin Regency using a purposive sampling survey method. Thirteen seedling locations were selected based on their adherence to good seedling criteria. Seedlings aged 6-12 months were used in this study. At each location, five plots were surveyed, with 30-32 seedlings sampled per plot. Supporting data, including fertilization, watering, and herbicide and fungicide application, were tabulated to supplement the research findings. Results indicated that brown spot disease can affect plants as young as two weeks old. Initial symptoms include brown spots that eventually widen and merge with other spots. The average incidence of the disease was 93.29 % (± 7.89), with an average severity of 47.13% (± 13.23).

Plastic Mulching Effects on Cotton Seedling and Wilt Disease, Lint Yields, and Yield Components

Plastic mulching is a widely used intensive planting system for cotton production in China. For the present study, the effects of three plastic mulching treatments (i.e., NDNM: normal sowing date with no plastic mulching as a positive control, NDM: normal sowing date with plastic mulching, and LDM: sowing 7 days late with plastic mulching) were studied in the field on seedling disease, Verticillium wilt, and Fusarium wilt as well as on the lint yield in cotton from 2019 to 2020. The treatment effects were evaluated based on the disease incidence (DI) and disease severity index (DSI), seedling fresh weights, lint yields, and yield components. For all cultivars (SCRC28, SCRC21, and Jimian11), both the DIs and DSIs of the seedling disease were lower in the LDM treatment than in the NDNM and NDM treatments. The DIs and DSIs of Fusarium wilt for all the cultivars were higher in the NDNM treatment than in the NDM and LDM treatments. However, the DIs and DSIs for Verticillium wilt were lower in the NDNM treatment. Moreover, the seedling fresh weights, average lint yields, and boll numbers per square meter were all highest in the NDM treatment and lowest in the NDNM treatment. The results of this study demonstrated that the use of plastic mulching with a suitable seed sowing date would be an appropriate cultural practice for enhancing cotton production and reducing the severity of cotton seedling and Fusarium wilt disease.

Effect of provenance on seed-borne Mycoflora, germination and seedling disease incidence on Khaya Senegalensis seeds in Ghana

Seed provenance is an important component determining seed quality in forest restorations. Collection of seeds from diseased-free agro-ecological zones for reforestation programs in Ghana is key. To contribute to knowledge, a research was conducted to assess the effect of provenance on seed-borne mycoflora prevalence, germination and initial seedling disease incidence of Khaya Senegalensis seeds in three agro-ecological zones of Ghana. Four seed-borne fungi in three genera namely Aspergillus niger, A. flavus, Colletotrichum sp. and Penicillium sp. were isolated from Khaya Senegalensis seeds collected from the three different provenances namely Deciduous forest, Transitional and Guinea Savannah zones. Total seed-borne mycoflora infections on Khaya Senegalensis varied significantly (p<0.05) between provenances. Transitional and Deciduous zones recorded equal highest incidence of 100.0% total seed-borne mycoflora infections whilst seeds from the Guinea Savannah zone recorded the least total seed-borne mycoflora infection of 58.3%. Significant differences (p<0.05) were observed between provenances with respect to seed germination. Seeds from Guinea Savannah zone recorded the highest (73.7%) whilst the least percentage (16.3%) germination was observed in seeds sourced from the Deciduous forest zone. There were no significant difference (p<0.05) for percent seedling disease incidence amongst provenances. However, the highest (20.0 %) seedling disease incidence was recorded in seeds sourced from Transitional zone whilst the least (12.5%) recorded in seeds from the Deciduous Forest zone. Provenance has significant effect on seed-borne mycoflora prevalence and seed germination. It is recommended that seeds be collected from provenances with low incidence of seed-borne mycoflora to enhance high seed germination for reforestation programs.

Identification of Fusarium oxysporum Causing Leaf Blight on Dendrobium chrysotoxum in Yunnan Province, China.

Leaf-blight disease caused by the Fusarium oxysporum is an emerging problem in Dendrobium chrysotoxum production in China. Symptoms of leaf blight were observed on seedlings of D. chrysotoxum cultivated in a nursery in Ruili City, Yunnan Province, China. In this study, we isolated the Fusarium sp. associated with leaf-blight disease of D. chrysotoxum from the diseased seedlings. A pathogenicity test was performed to fulfill Koch's postulates to confirm the pathogenicity of isolated strains and identified using morphological and molecular techniques. The results revealed that all four isolated Fusarium sp. isolates (DHRL-01~04) produced typical blight symptoms followed by marginal necrosis of leaves on the D. chrysotoxum plants. On the PDA medium, the fungal colony appeared as a white to purplish color with cottony mycelium growth. Microconidia are oval-shaped, whereas macroconidia are sickle-shaped, tapering at both ends with 2-4 septations. The phylogenetic trees were construed based on internal transcribed spacer (ITS), translation elongation factor (EF-1α), and RNA polymerase subunit genes RPB1 and RPB2 genes, respectively, and blasted against the NCBI database for species confirmation. Based on the NCBI database's blast results, the isolates showed that more than 99% identify with Fusarium oxysporum. To our knowledge, this is the first comprehensive report on the identification of Fusarium oxysporum as the causal agent of Dendrobium chrysotoxum leaf blight in Yunnan Province, China, based on morphological and molecular characteristics.

Identification and Characterization of Nigrospora Species and a Novel Species, Nigrospora anhuiensis, Causing Black Leaf Spot on Rice and Wild Rice in the Anhui Province of China.

Rice production in the Anhui province is threatened by fungal diseases. We obtained twenty-five fungal isolates from rice and wild rice leaves showing leaf spot disease collected along the Yangtze River. A phylogenetic analysis based on internal transcribed spacer (ITS), translation elongation factor 1 alpha (TEF1-α), and beta tubulin (TUB2) sequences revealed one isolate (SS-2-JB-1B) grouped with Nigrospora sphaerica, one (QY) with Nigrospora chinensis, twenty-two with Nigrospora oryzae, and one isolate (QY-2) grouped in its own clade, which are related to but clearly different from N. oryzae. Nineteen tested isolates, including sixteen strains from the N. oryzae clade and the three isolates of the other three clades, caused disease on detached rice leaves. The three isolates that did not belong to N. oryzae were also able to cause disease in rice seedlings, suggesting that they were rice pathogens. Isolate QY-2 differed from the other isolates in terms of colony morphology, cell size, and susceptibility to fungicides, indicating that this isolate represents a new species that we named Nigrospora anhuiensis. Our analysis showed that N. sphaerica, N. chinensis, and the new species, N. anhuiensis, can cause rice leaf spot disease in the field. This research provides new knowledge for understanding rice leaf spot disease.

Fusarium clavum causes sugar beet seedling root rot in Wyoming, USA

Seedling rot in sugar beet was observed at Snyder Farms, Wyoming, USA, in April 2022. The diseased seedlings exhibited water-soaked brown to blackish lesions in hypocotyls with poor root systems. Four fungal isolates were retrieved from the diseased samples, and their morphological features were found to be identical to those of previously reported Fusarium species. Artificial inoculation with isolates developed similar symptoms to those observed in the field samples. Based on morphological characteristics, pathogenicity assays, sequence homologies of the internal transcribed spacer, translation elongation factor (tef1α), largest subunit of RNA polymerase II (rpb2), β-tubulin (β-tub), and multilocus phylogenic analyses with tef1α and rpb2, the causal agent was identified as Fusarium clavum (F. incarnatum-equiseti species complex 5). This is the first worldwide report of sugar beet seedling rot caused by F. clavum, detected in Wyoming, USA. This finding will help to formulate effective management practices to manage the pathogen and prevent its widespread occurrence.

Pengaruh Sifat Tanah Terhadap Kejadian dan Keparahan Penyakit pada Kelapa Sawit Main Nursery

Soil properties, both physical, chemical and biological, have a direct impact on the growth and health of oil palm seedlings. Fertile soil means the incidence and severity of plant diseases can be minimized. For this reason, research is needed to examine the influence of soil properties on the incidence and severity of disease in oil palm seedlings in the main nursery phase. The aim is to determine soil properties, both physical and chemical, that influence the incidence and severity of main nursery oil palm diseases. Implementation stages include taking soil samples and observing sick plants. The soil sample taken was the rhizosphere of main nursery oil palm. Data analysis uses Microsoft Excel to describe disease incidence and soil physical and chemical properties. The research results showed that in main nursery-B (MN-B) the incidence of disease attacks had a higher percentage compared to main nursery-A (MN-A). Physical and chemical properties of soil (N-available, P-available, C-organic, CEC) influence the incidence of disease attacks. The high content of available N and available P increases attacks by plant pests, while the high content of organic C and CEC can suppress pest attacks.

Ocena pokazatelja kvaliteta semena hibrida paprike tokom klijanja

The aim of the research was to evaluate the influence of the hybrid and the medium for germination testing on indicators of pepper seed quality. The obtained results should provide an answer as to whether the application of different growing media for testing seed germination can lead to discrepancies between test results in quality indicators for hybrid seeds. The seed quality of three pepper hybrids: KG 2025 F1, KG 2129 F1 and KG 2032 F1 was tested on two growing media (filter paper and substrate). Statistical analysis of germination energy, total germination, diseased seedlings and dead seeds showed highly significant differences (r<0.01) under the influence of the hybrid factor. The growing media factor also had a highly significant effect on all examined quality indicators , except for total germination. A significantly lower number of abnormal and diseased seedlings was found on the filter paper compared to the substrate. A highly negative significant correlation (r =-0.90951, p≤0.001) was recorded only between total germination and diseased seedlings. The obtained results indicate that the application of different media for testing the germination of hybrid pepper seeds can lead to inconsistencies in the obtained values for all evaluated quality indicators.

Online diagnosis platform for tomato seedling diseases in greenhouse production

Online diagnosis platform for tomato seedling diseases in greenhouse production

Sixteen Novel Mycoviruses Containing Positive Single-Stranded RNA, Double-Stranded RNA, and Negative Single-Stranded RNA Genomes Co-Infect a Single Strain of Rhizoctonia zeae.

In the present study, sixteen novel RNA mycoviruses co-infecting a single strain of Rhizoctonia zeae (strain D40) were identified and molecularly characterized using metatranscriptome sequencing combined with a method for rapid amplification of cDNA ends. The fungal strain was isolated from diseased seedlings of sugar beet with damping-off symptoms. Based on genome analysis and phylogenetic analysis of amino acid sequences of RNA-dependent RNA polymerase, the sixteen mycoviruses associated with strain D40 contained three genome types with nine distinct lineages, including positive single-stranded RNA (Hypoviridae, Yadokariviridae, Botourmiaviridae, and Gammaflexiviridae), double-stranded RNA (Phlegiviridae, Megabirnaviridae, Megatotiviridae, and Yadonushiviridae), and negative single-stranded RNA (Tulasviridae), suggesting a complex composition of a mycoviral community in this single strain of R. zeae (strain D40). Full genome sequences of six novel mycoviruses and the nearly full-length sequences of the remaining ten novel mycoviruses were obtained. Furthermore, seven of these sixteen mycoviruses were confirmed to assemble virus particles present in the R. zeae strain D40. To the best of our knowledge, this is the first detailed study of mycoviruses infecting R. zeae.

Incidence and severity of fungal seedling diseases in Tamale central forest nursery, Ghana

Fungal diseases cause serious seedling mortality in nurseries and threaten future seedling production for forest regeneration. To abate this menace, knowledge about them is key. Therefore, this study aimed at determining the incidence and severity of fungal diseases of forest seedlings in the Central Forest Nursery of Tamale, Ghana. Khaya senegalensis, Tectona grandis and Polyalthia longifolia in the nursery were infected with eight fungal pathogens and an unidentified fungus causing leaf blight, wilt, and dumping-off diseases. The pathogens included Rhizoctonia sp., Fusarium sp., Corrynespora sp., Colletotrichum sp., Cercospora sp., Phytophthora sp., Chaetomium sp., and Macrophomina sp. Rhizoctonia was the dominant pathogen isolated from all the leaves of the seedling species. Colletotrichum and Chaetomium were isolated from the leaves of Polyalthia longifolia. Cercospora and an unidentified spp. were found on the stems of Tectona grandis. Fusarium and Phytophthora were respectively found on Polyalthia longifolia and Khaya senegalensis stems. Chaetomium was identified on both Polyalthia longifolia and Khaya senegalensis stems. Cercospora and Fusarium were isolated from the roots of Tectona grandis and Polyalthia longifolia respectively while Macrophomina was associated with both Tectona grandis and Khaya senegalensis roots. Leaf blight recorded the highest disease incidence (76.7%) and affected all the three seedling species. Wilt disease showed low incidence (10.2-15.8 %) among the different seedling species. Dumping-off disease incidence (10.4%) was only recorded in Khaya senegalensis. The severities of the diseases identified were low (1-2) score except leaf blight of Tectona grandis and Polyalthia longifolia recording a moderate (3.0) severity score. It is recommended that appropriate disease management strategies be employed to prevent high incidences and severities.

Disease of forest tree seedlings (Article Review)

Nursery are one of the most important reasons for the success and progress of the agricultural renaissance, as it depends on the application of various advanced scientific methods and the use of Nursery of various types in the propagation and production of forest seedlings and others. A greenhouse is a place where small plants are produced to plant them in gardens, fields, and trees. The plants produced by the greenhouse vary between ornamental plants and flowers, fruit plants, vegetables, and forest trees, and Nursery are often held for commercial purposes.The incidence of Nursery diseases increases from what happens in the forests through the increase in service operations and attention to irrigation and fertilization and not sterilizing the soil and seeds, as this appears on the resulting seedlings, and the seedlings resulting from Nursery can be a source of transmission of infection when artificial afforestation is performed. Therefore, we must monitor and ensure the safety of the productive seedlings. The disease of Root rot and seedling disease Damping-off are one of the most critical diseases found in forest Nursery and the most widespread throughout the hot and cold world. As these diseases affect many forest plants, it is preferable to study them to avoid infecting forest species through the correct management of these Nursery by sterilizing the soil and seeds, as well as regular irrigation and correct fertilization.

Genome-wide association study on resistance of cultivated soybean to Fusarium oxysporum root rot in Northeast China

BackgroundFusarium oxysporum is a prevalent fungal pathogen that diminishes soybean yield through seedling disease and root rot. Preventing Fusarium oxysporum root rot (FORR) damage entails on the identification of resistance genes and developing resistant cultivars. Therefore, conducting fine mapping and marker development for FORR resistance genes is of great significance for fostering the cultivation of resistant varieties. In this study, 350 soybean germplasm accessions, mainly from Northeast China, underwent genotyping using the SoySNP50K Illumina BeadChip, which includes 52,041 single nucleotide polymorphisms (SNPs). Their resistance to FORR was assessed in a greenhouse. Genome-wide association studies utilizing the general linear model, mixed linear model, compressed mixed linear model, and settlement of MLM under progressively exclusive relationship models were conducted to identify marker-trait associations while effectively controlling for population structure.ResultsThe results demonstrated that these models effectively managed population structure. Eight SNP loci significantly associated with FORR resistance in soybean were detected, primarily located on Chromosome 6. Notably, there was a strong linkage disequilibrium between the large-effect SNPs ss715595462 and ss715595463, contributing substantially to phenotypic variation. Within the genetic interval encompassing these loci, 28 genes were present, with one gene Glyma.06G088400 encoding a protein kinase family protein containing a leucine-rich repeat domain identified as a potential candidate gene in the reference genome of Williams82. Additionally, quantitative real-time reverse transcription polymerase chain reaction analysis evaluated the gene expression levels between highly resistant and susceptible accessions, focusing on primary root tissues collected at different time points after F. oxysporum inoculation. Among the examined genes, only this gene emerged as the strongest candidate associated with FORR resistance.ConclusionsThe identification of this candidate gene Glyma.06G088400 improves our understanding of soybean resistance to FORR and the markers strongly linked to resistance can be beneficial for molecular marker-assisted selection in breeding resistant soybean accessions against F. oxysporum.

Effect of Infection Timing by Four Pythium spp. on Soybean Damping-Off Symptoms with and Without Cold Stress.

Pythium spp. cause damping-off of soybean, especially when soil conditions at or shortly after planting are cool and wet. Soybean planting dates continue to shift to earlier dates, so germinating seed and seedlings are exposed to periods of cold stress at a time which favors infection by Pythium, and seedling disease occurs. The objective of this study was to assess infection timing and cold stress on soybean seedling disease severity caused by four Pythium spp. prevalent in Iowa, namely P. lutarium, P. oopapillum, P. sylvaticum, and P. torulosum. Each species was used individually to inoculate soybean cultivar 'Sloan' using a rolled towel assay. Two temperature treatments (continuous 18°C [C18]; a 48-h cold stress period at 10°C [CS]) were applied. Soybean seedling age was divided into five growth stages (GS1 to GS5). Root rot severity and root length were assessed at 2, 4, 7, and 10 days after inoculation (DAI). At C18, root rot was greatest when soybean was inoculated with P. lutarium or P. sylvaticum at GS1 (seed imbibes water) and with P. oopapillum or P. torulosum at GS1, GS2 (radicle elongation), and GS3 (hypocotyl emergence). After CS, soybean susceptibility to P. lutarium and P. sylvaticum was reduced compared to C18 for inoculation at all GSs except GS5 (unifoliate leaf emergence). Conversely, root rot by P. oopapillum and P. torulosum was greater after CS compared to C18. Data from this study demonstrate that greater root rot, and consequently more damping-off, is likely if infection occurs at early germination stages before seedling emergence.

Identification and Percentage of Disease Pathogen Attacks on Primary Palm Oil Crops

The aim of this research is to identify and determine the percentage of diseases caused by fungi in oil palm seedlings. The purposive sampling method and the objects observed were fungi that cause disease in oil palm seedlings microscopically at the Jambi Class 1 Agricultural Quarantine Laboratory. The results of the research found that Curvularia sp disease had a percentage of attacks in nursery one (f?) of 25%, while the intensity of attacks in nursery one (f?) was 5%, in nursery two (f?) the percentage of attacks was 25% while the intensity of attacks in nursery two (f?) 6%, and in the third nursery (f?) the attack percentage was 10%, while the attack intensity in the third nursery (f?) was 2%. The percentage of attacks by Pestalotiopsis sp in nursery one (f?) is 20%, while the intensity of attacks in nursery one (f?) is 4%, in nursery two (f?) the percentage of attacks is 5%, while the intensity of attacks in nursery two (f?) is 1%, and in nursery three (f?) attack percentage was 20% while the attack intensity in the three (f?) nursery was 4%. From this research, it was concluded that two diseases were found in oil palm seedlings, namely Curvularia sp leaf spot and Pestalotiopsis sp leaf spot.

Identification and characterization of Fusarium falciforme, incitant of wilt disease in cashew seedlings and its management

The present study was carried out to identify and characterize the pathogen responsible for cashew seedling wilt, and to find its control measures. Characteristic symptoms of wilt included yellowing and drying of the lower leaves at the initial stage. In the advanced stage, drooping and wilting of the top portion of the seedling was more common. Pathogen Fusarium falciforme, was identified based on the morphological characteristics and ITS sequence data. Several fungicidal formulations effectively reduced the intensity and severity of seedling wilt disease. Phylogenetic analysis placed all the five isolates into a single cluster. A mixture of Trifloxystrobin and Tebuconazole inhibited the pathogen in terms of mycelial growth, followed by Carbendazim + Mancozeb with ED50 values of 4.370 and 8.427 ppm, respectively. However, mixture of Carbendazim and Mancozeb was found the best suitable fungicide formulation to reduce the severity of wilt disease and the highest percent disease control over the untreated one.

Serendipita indica as a Plant Growth Promoter and Biocontrol Agent against Black Rot Disease in Cabbage Grown in a Phytotron

Serendipita indica, a mutualistic root endophytic fungus, has gained attention for its potential to enhance plant health and resistance to various stresses. This study investigated the impact of S. indica (strain DSM 11827) on plant growth promotion and the management of black rot disease. This is a devastating bacterial ailment caused by Xanthomonas campestris pv. campestris, which affects cruciferous crops worldwide. The experiment was conducted under sterile conditions in a phytotron for 10 weeks. It involved the substrate and seed inoculation of S. indica in a cabbage crop. The findings suggested that S. indica establishes mutualistic relationships with cruciferous plants, positively influencing their growth while simultaneously reducing their susceptibility to black rot disease. Plant morphological and physiological parameters were enhanced by S. indica application. Additionally, bio stress markers were also enhanced in response to black rot disease. Moreover, disease severity was reduced by 27.9% and 18.8% in the substrate and seeds treated with S. indica, respectively. However, our findings did not report any antagonistic effect between S. indica and two pathogens, i.e., Xanthomonas campestris pv. campestris and Alternaria brassicicola under the in vitro test, suggesting that the suppression of black rot disease in cabbage seedlings was induced indirectly by S. indica. This study, therefore, underscores the promising prospect of utilizing S. indica to promote crop productivity and combat the destructive impact of black rot disease in cruciferous plants, contributing to more sustainable and resilient agriculture.

Not All Acidovorax Are Created Equal: Gibberellin Biosynthesis in the Turfgrass Pathogen Acidovorax avenae subsp. avenae.

In recent years Acidovorax avenae subsp. avenae was identified as a major cause of bacterial etiolation and decline (BED) in turfgrasses and has become a growing economical concern for the turfgrass industry. The symptoms of BED resemble those of "bakanae," or foolish seedling disease, of rice (Oryzae sativa), in which the gibberellins produced by the infecting fungus, Fusarium fujikuroi, contribute to the symptom development. Additionally, an operon coding for the enzymes necessary for bacterial gibberellin production was recently characterized in plant-pathogenic bacteria belonging to the γ-proteobacteria. We therefore investigated whether this gibberellin operon might be present in A. avenae subsp. avenae. A homolog of the operon has been identified in two turfgrass-infecting A. avenae subsp. avenae phylogenetic groups but not in closely related phylogenetic groups or strains infecting other plants. Moreover, even within these two phylogenetic groups, the operon presence is not uniform. For that reason, the functionality of the operon was examined in one strain of each turfgrass-infecting phylogenetic group (A. avenae subsp. avenae strains KL3 and MD5). All nine operon genes were functionally characterized through heterologous expression in Escherichia coli and enzymatic activities were analyzed by liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry. All enzymes were functional in both investigated strains, thus demonstrating the ability of phytopathogenic β-proteobacteria to produce biologically active GA4. This additional gibberellin produced by A. avenae subsp. avenae could disrupt phytohormonal balance and be a leading factor contributing to the pathogenicity on turf grasses. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.