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Jeong SK, Han SE, Vasantha-Srinivasan P, Jung WJ, Maung CEH, Kim KY. Agro Active Potential of Bacillus subtilis PE7 against Didymella bryoniae (Auersw.), the Causal Agent of Gummy Stem Blight of Cucumis melo. Microorganisms 2024; 12:1691. [PMID: 39203532 PMCID: PMC11357386 DOI: 10.3390/microorganisms12081691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2024] [Revised: 07/27/2024] [Accepted: 08/13/2024] [Indexed: 09/03/2024] Open
Abstract
Microbial agents such as the Bacillus species are recognized for their role as biocontrol agents against various phytopathogens through the production of diverse bioactive compounds. This study evaluates the effectiveness of Bacillus subtilis PE7 in inhibiting the growth of Didymella bryoniae, the pathogen responsible for gummy stem blight (GSB) in cucurbits. Dual culture assays demonstrate significant antifungal activity of strain PE7 against D. bryoniae. Volatile organic compounds (VOCs) produced by strain PE7 effectively impede mycelial formation in D. bryoniae, resulting in a high inhibition rate. Light microscopy revealed that D. bryoniae hyphae exposed to VOCs exhibited abnormal morphology, including swelling and excessive branching. Supplementing a potato dextrose agar (PDA) medium with a 30% B. subtilis PE7 culture filtrate significantly decreased mycelial growth. Moreover, combining a 30% culture filtrate with half the recommended concentration of a chemical fungicide yielded a more potent antifungal effect than using the full fungicide concentration alone, inducing dense mycelial formation and irregular hyphal morphology in D. bryoniae. Strain PE7 was highly resilient and was able to survive in fungicide solutions. Additionally, B. subtilis PE7 enhanced the nutrient content, growth, and development of melon plants while mitigating the severity of GSB compared to fungicide and fertilizer treatments. These findings highlight B. subtilis PE7 as a promising biocontrol candidate for integrated disease management in crop production.
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Affiliation(s)
- Seo Kyoung Jeong
- Department of Plant Protection and Quarantine, Chonnam National University, Gwangju 61186, Republic of Korea; (S.K.J.); (W.J.J.)
| | - Seong Eun Han
- Department of Agricultural Chemistry, Environmentally-Friendly Agricultural Research Center, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Republic of Korea;
| | - Prabhakaran Vasantha-Srinivasan
- Department of Applied Biology, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Republic of Korea;
| | - Woo Jin Jung
- Department of Plant Protection and Quarantine, Chonnam National University, Gwangju 61186, Republic of Korea; (S.K.J.); (W.J.J.)
- Department of Agricultural Chemistry, Environmentally-Friendly Agricultural Research Center, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Republic of Korea;
| | - Chaw Ei Htwe Maung
- Department of Agricultural Chemistry, Environmentally-Friendly Agricultural Research Center, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Republic of Korea;
| | - Kil Yong Kim
- Department of Plant Protection and Quarantine, Chonnam National University, Gwangju 61186, Republic of Korea; (S.K.J.); (W.J.J.)
- Department of Agricultural Chemistry, Environmentally-Friendly Agricultural Research Center, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Republic of Korea;
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Wang H, Wei X, Mo C, Wei M, Li Y, Fan Y, Gu X, Zhang X, Zhang Y, Kong Q. Integrated full-length transcriptome and metabolome analysis reveals the defence response of melon to gummy stem blight. PLANT, CELL & ENVIRONMENT 2024; 47:1997-2010. [PMID: 38379450 DOI: 10.1111/pce.14865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 01/30/2024] [Accepted: 02/12/2024] [Indexed: 02/22/2024]
Abstract
Gummy stem blight (GSB), a widespread disease causing great loss to cucurbit production, has become a major threat to melon cultivation. However, the melon-GSB interaction remains largely unknown. Here, full-length transcriptome and widely targeted metabolome were used to investigate the defence responses of resistant (PI511089) and susceptible (Payzawat) melon accessions to GSB pathogen infection at 24 h. The biosynthesis of secondary metabolites and MAPK signalling pathway were specifically enriched for differentially expressed genes in PI511890, while carbohydrate metabolism and amino acid metabolism were specifically enriched in Payzawat. More than 1000 novel genes were identified and MAPK signalling pathway was specifically enriched for them in PI511890. There were 11 793 alternative splicing events involving in the defence response to GSB. Totally, 910 metabolites were identified in Payzawat and PI511890, and flavonoids were the dominant metabolites. Integrated full-length transcriptome and metabolome analysis showed eriodictyol and oxalic acid were the potential marker metabolites for GSB resistance in melon. Moreover, posttranscription regulation was widely involved in the defence response of melon to GSB pathogen infection. These results not only improve our understanding on the interaction between melon and GSB, but also facilitate the genetic improvement of melon with GSB resistance.
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Affiliation(s)
- Haiyan Wang
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Xiaoying Wei
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Changjuan Mo
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Minghua Wei
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Yaqiong Li
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Yuxin Fan
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Xiaojing Gu
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Xuejun Zhang
- Hami-Melon Research Center, Xinjiang Academy of Agricultural Sciences, Urumqi, China
| | - Yongbing Zhang
- Hami-Melon Research Center, Xinjiang Academy of Agricultural Sciences, Urumqi, China
| | - Qiusheng Kong
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China
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Seblani R, Keinath AP, Munkvold G. Gummy stem blight: One disease, three pathogens. MOLECULAR PLANT PATHOLOGY 2023; 24:825-837. [PMID: 37129449 PMCID: PMC10346371 DOI: 10.1111/mpp.13339] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 02/28/2023] [Accepted: 03/06/2023] [Indexed: 05/03/2023]
Abstract
Gummy stem blight (GSB) is a major disease of cucurbits worldwide. It is caused by three fungal species that are morphologically identical and have overlapping geographic and host ranges. Controlling GSB is challenging due to the lack of resistant cultivars and the pathogens' significant ability to develop resistance to systemic fungicides. The causal agent of GSB is recognized as a complex of three phylogenetically distinct species belonging to domain Eukaryota, kingdom Fungi, phylum Ascomycota, subphylum Pezizomycotina, class Dothideomycetes, subclass Pleosporomycetida, order Pleosporales, family Didymellaceae, genus Stagonosporopsis, species cucurbitacearum, citrulli, and caricae. Pycnidia are tan with dark rings of cells around the ostiole measuring 120-180 μm in diameter. Conidia are 6-13 μm long, hyaline, cylindrical with round ends, and non- or monoseptate. Pseudothecia are black and globose in shape and have a diameter of 125-213 μm. Ascospores are 14-18 × 4-6 μm long, hyaline, ellipsoidal with round ends, and monoseptate with a distinct constriction at the septum. Eight ascospores are found per ascus. The upper end of the apical cell is pointed, whereas the lower end of the bottom cell is blunt. Species-specific PCR primers that can be used in a multiplex conventional PCR assay are available. The GSB species complex is pathogenic to 37 species of cucurbits from 21 different genera. S. cucurbitacearum and S. citrulli are specific to cucurbits, while S. caricae is also pathogenic to papaya and babaco-mirim (Vasconcellea monoica), a related fruit. Under favourable environmental conditions, symptoms can appear 3-12 days after spore germination. Leaf spots often start at the leaf margin or extend to the margins. Spots expand and coalesce, resulting in leaf blighting. Active lesions are typically water-soaked. Cankers are observed on crowns, main stems, and vines. Red to amber gummy exudates are often seen on the stems after cankers develop on cortical tissue.
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Affiliation(s)
- Rewa Seblani
- Plant Pathology, Entomology, and MicrobiologyIowa State UniversityAmesIowaUSA
| | | | - Gary Munkvold
- Plant Pathology, Entomology, and MicrobiologyIowa State UniversityAmesIowaUSA
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Murolo S, Moumni M, Mancini V, Allagui MB, Landi L, Romanazzi G. Detection and Quantification of Stagonosporopsis cucurbitacearum in Seeds of Cucurbita maxima Using Droplet Digital Polymerase Chain Reaction. Front Microbiol 2022; 12:764447. [PMID: 35087483 PMCID: PMC8788924 DOI: 10.3389/fmicb.2021.764447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 12/15/2021] [Indexed: 11/27/2022] Open
Abstract
Stagonosporopsis cucurbitacearum is an important seedborne pathogen of squash (Cucurbita maxima). The aim of our work was to develop a rapid and sensitive diagnostic tool for detection and quantification of S. cucurbitacearum in squash seed samples, to be compared with blotter analysis, that is the current official seed test. In blotter analysis, 29 of 31 seed samples were identified as infected, with contamination from 1.5 to 65.4%. A new set of primers (DB1F/R) was validated in silico and in conventional, quantitative real-time PCR (qPCR) and droplet digital (dd) PCR. The limit of detection of S. cucurbitacearum DNA for conventional PCR was ∼1.82 × 10–2 ng, with 17 of 19 seed samples positive. The limit of detection for ddPCR was 3.6 × 10–3 ng, which corresponded to 0.2 copies/μl. Detection carried out with artificial samples revealed no interference in the absolute quantification when the seed samples were diluted to 20 ng. All seed samples that showed S. cucurbitacearum contamination in the blotter analysis were highly correlated with the absolute quantification of S. cucurbitacearum DNA (copies/μl) in ddPCR (R2 = 0.986; p ≤ 0.01). Our ddPCR protocol provided rapid detection and absolute quantification of S. cucurbitacearum, offering a useful support to the standard procedure.
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Affiliation(s)
- Sergio Murolo
- Department of Agricultural, Food and Environmental Sciences, Marche Polytechnic University, Ancona, Italy
| | - Marwa Moumni
- Department of Agricultural, Food and Environmental Sciences, Marche Polytechnic University, Ancona, Italy.,Laboratory of Plant Protection, National Institute for Agronomic Research of Tunisia, University of Carthage, Ariana, Tunisia
| | - Valeria Mancini
- Department of Agricultural, Food and Environmental Sciences, Marche Polytechnic University, Ancona, Italy
| | - Mohamed Bechir Allagui
- Laboratory of Plant Protection, National Institute for Agronomic Research of Tunisia, University of Carthage, Ariana, Tunisia
| | - Lucia Landi
- Department of Agricultural, Food and Environmental Sciences, Marche Polytechnic University, Ancona, Italy
| | - Gianfranco Romanazzi
- Department of Agricultural, Food and Environmental Sciences, Marche Polytechnic University, Ancona, Italy
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Dong ZY, Huang YH, Manawasinghe IS, Wanasinghe DN, Liu JW, Shu YX, Zhao MP, Xiang MM, Luo M. Stagonosporopsis pogostemonis: A Novel Ascomycete Fungus Causing Leaf Spot and Stem Blight on Pogostemon cablin (Lamiaceae) in South China. Pathogens 2021; 10:pathogens10091093. [PMID: 34578126 PMCID: PMC8465882 DOI: 10.3390/pathogens10091093] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 08/24/2021] [Accepted: 08/24/2021] [Indexed: 11/16/2022] Open
Abstract
Pogostemon cablin is one of the well-known Southern Chinese medicinal plants with detoxification, anti-bacterial, anti-inflammatory, and other pharmacological functions. Identification and characterization of phytopathogens on P. cablin are of great significance for the prevention and control of diseases. From spring to summer of 2019 and 2020, a leaf spot disease on Pogostemon cablin was observed in Guangdong Province, South China. The pathogen was isolated and identified based on both morphological and DNA molecular approaches. The molecular identification was conducted using multi-gene sequence analysis of large subunit (LSU), the nuclear ribosomal internal transcribed spacer (ITS), beta-tubulin (β-tubulin), and RNA polymerase II (rpb2) genes. The causal organism was identified as Stagonosporopsis pogostemonis, a novel fungal species. Pathogenicity of Stagonosporopsis pogostemonis on P. cablin was fulfilled via confining the Koch's postulates, causing leaf spots and stem blight disease. This is the first report of leaf spot diseases on P. cablin caused by Stagonosporopsis species worldwide.
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Affiliation(s)
- Zhang-Yong Dong
- Innovative Institute for Plant Health, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China; (Z.-Y.D.); (Y.-H.H.); (J.-W.L.); (Y.-X.S.); (M.-P.Z.); (M.-M.X.)
| | - Ying-Hua Huang
- Innovative Institute for Plant Health, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China; (Z.-Y.D.); (Y.-H.H.); (J.-W.L.); (Y.-X.S.); (M.-P.Z.); (M.-M.X.)
| | - Ishara S. Manawasinghe
- Innovative Institute for Plant Health, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China; (Z.-Y.D.); (Y.-H.H.); (J.-W.L.); (Y.-X.S.); (M.-P.Z.); (M.-M.X.)
- Correspondence: (I.S.M.); (M.L.); Tel.: +86-2089003192 (I.S.M. & M.L.)
| | - Dhanushka N. Wanasinghe
- Center for Mountain Futures, Kunming Institute of Botany, Chinese Academy of Sciences, Honghe 654400, China;
| | - Jia-Wei Liu
- Innovative Institute for Plant Health, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China; (Z.-Y.D.); (Y.-H.H.); (J.-W.L.); (Y.-X.S.); (M.-P.Z.); (M.-M.X.)
| | - Yong-Xin Shu
- Innovative Institute for Plant Health, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China; (Z.-Y.D.); (Y.-H.H.); (J.-W.L.); (Y.-X.S.); (M.-P.Z.); (M.-M.X.)
| | - Min-Ping Zhao
- Innovative Institute for Plant Health, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China; (Z.-Y.D.); (Y.-H.H.); (J.-W.L.); (Y.-X.S.); (M.-P.Z.); (M.-M.X.)
| | - Mei-Mei Xiang
- Innovative Institute for Plant Health, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China; (Z.-Y.D.); (Y.-H.H.); (J.-W.L.); (Y.-X.S.); (M.-P.Z.); (M.-M.X.)
| | - Mei Luo
- Innovative Institute for Plant Health, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China; (Z.-Y.D.); (Y.-H.H.); (J.-W.L.); (Y.-X.S.); (M.-P.Z.); (M.-M.X.)
- Correspondence: (I.S.M.); (M.L.); Tel.: +86-2089003192 (I.S.M. & M.L.)
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Albuquerque BR, Dias MI, Pereira C, Petrović J, Soković M, Calhelha RC, Oliveira MBPP, Ferreira ICFR, Barros L. Valorization of Sicanaodorifera (Vell.) Naudin Epicarp as a Source of Bioactive Compounds: Chemical Characterization and Evaluation of Its Bioactive Properties. Foods 2021; 10:foods10040700. [PMID: 33806049 PMCID: PMC8064462 DOI: 10.3390/foods10040700] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 03/17/2021] [Accepted: 03/22/2021] [Indexed: 11/16/2022] Open
Abstract
Fruit bio-residues can be interesting for the recovery of bioactive molecules, such as phenolic compounds, tocopherols, vitamins, among others. These compounds can be targeted at the food industry and used for the development of functional foods or as food additives. In some cases, fruit epicarps are converted into by-products with non-commercial value, and generally, these fruit parts have a higher content in bioactive compounds than the fruit pulp. From this perspective, S. odorifera, a Brazilian fruit, has an inedible epicarp that could be explored to obtain biological compounds. Therefore, the aims of this study were to evaluate the chemical composition and the antioxidant, anti-proliferative, anti-inflammatory, and antimicrobial bioactivities of this by-product. S. odorifera epicarp showed a total of four organic acids, four phenolic compounds, highlighting the high concentration of anthocyanins (24 ± 1 mg/g dry weight (dw)) and high content of tocopherols (366 ± 2 mg/100 g dw). The hydroethanolic extract showed considerable antioxidant activity (EC50 values of 48.2 ± 0.5 and 27 ± 1 µg/mL for TBARS and OxHLIA assays, respectively), as also antibacterial and antifungal activities (minimal inhibitory concentrations (MICs) ≤ 2.2 mg/mL). The results obtained in this study suggest that Sicana odorifera epicarp represents a reliable option for the development of novel natural-based colorants with functional/bioactive proprieties.
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Affiliation(s)
- Bianca R. Albuquerque
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal; (B.R.A.); (M.I.D.); (C.P.); (R.C.C.); (I.C.F.R.F.)
- REQUIMTE—Science Chemical Department, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal;
| | - Maria Inês Dias
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal; (B.R.A.); (M.I.D.); (C.P.); (R.C.C.); (I.C.F.R.F.)
| | - Carla Pereira
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal; (B.R.A.); (M.I.D.); (C.P.); (R.C.C.); (I.C.F.R.F.)
| | - Jovana Petrović
- Institute for Biological Research “Siniša Stanković”, Department of Plant Physiology, University of Belgrade, Bulevar Despota Stefana 142, 11000 Belgrade, Serbia; (J.P.); (M.S.)
| | - Marina Soković
- Institute for Biological Research “Siniša Stanković”, Department of Plant Physiology, University of Belgrade, Bulevar Despota Stefana 142, 11000 Belgrade, Serbia; (J.P.); (M.S.)
| | - Ricardo C. Calhelha
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal; (B.R.A.); (M.I.D.); (C.P.); (R.C.C.); (I.C.F.R.F.)
| | - M. Beatriz P. P. Oliveira
- REQUIMTE—Science Chemical Department, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal;
| | - Isabel C. F. R. Ferreira
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal; (B.R.A.); (M.I.D.); (C.P.); (R.C.C.); (I.C.F.R.F.)
| | - Lillian Barros
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal; (B.R.A.); (M.I.D.); (C.P.); (R.C.C.); (I.C.F.R.F.)
- Correspondence: ; Tel.: +351-2-7333-0901
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Moumni M, Allagui MB, Mancini V, Murolo S, Tarchoun N, Romanazzi G. Morphological and Molecular Identification of Seedborne Fungi in Squash ( Cucurbita maxima, Cucurbita moschata). PLANT DISEASE 2020; 104:1335-1350. [PMID: 32223640 DOI: 10.1094/pdis-04-19-0741-re] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Squash is one of the most important crops of tropical and temperate regions, and it can be affected by several fungal pathogens. Most of these pathogens infect the seeds, which become an efficient vehicle to disperse seedborne pathogens over long distances, with consequent severe crop losses. The main objective of this study was the identification of the principal seedborne fungi in seeds extracted from 66 samples of asymptomatic and symptomatic squash fruit (Cucurbita maxima, Cucurbita moschata) collected in two countries, Tunisia and Italy. The symptoms of fruit decay were identified and classified according to lesion size. Following the blotter test, 14 fungal species were detected from the seeds. Seedborne fungi were identified in all fruit samples tested, including asymptomatic fruit. The most frequent fungi from Tunisian seeds were Alternaria alternata (25.1%), followed by Stagonosporopsis cucurbitacearum (24.6%), Fusarium solani (16.6%), Rhizopus stolonifer (13.3%), F. fujikuroi (7.8%), Albifimbria verrucaria (3.3%), and Stemphylium vesicarium (2.3%). For the fruits from Italy, the most frequently identified fungal species in seed samples were Alternaria alternata (40.0%), followed by F. fujikuroi (20.8%), Stemphylium vesicarium (3.0%), and Curvularia spicifera (2.1%). Morphological identification was confirmed by molecular diagnosis using the available species-specific primers. Furthermore, specific primers were designed to identify Albifimbria verrucaria, Paramyrothecium roridum, and Stemphylium vesicarium. Application of seed-health testing methods, including such conventional and molecular diagnostic tools, will help to improve seed quality and crop yields.
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Affiliation(s)
- Marwa Moumni
- Department of Agricultural, Food and Environmental Sciences, Marche Polytechnic University, 60131 Ancona, Italy
- National Agricultural Institute of Tunisia, 1082 Tunis, Tunisia
- Laboratory of Plant Protection, National Institute for Agronomic Research of Tunisia, University of Carthage, 2080 Ariana, Tunisia
| | - Mohamed Bechir Allagui
- Laboratory of Plant Protection, National Institute for Agronomic Research of Tunisia, University of Carthage, 2080 Ariana, Tunisia
| | - Valeria Mancini
- Department of Agricultural, Food and Environmental Sciences, Marche Polytechnic University, 60131 Ancona, Italy
| | - Sergio Murolo
- Department of Agricultural, Food and Environmental Sciences, Marche Polytechnic University, 60131 Ancona, Italy
| | - Neji Tarchoun
- Laboratory of Vegetable Crops, High Agronomic Institute of Chott Mariem, Sousse, Tunisia
| | - Gianfranco Romanazzi
- Department of Agricultural, Food and Environmental Sciences, Marche Polytechnic University, 60131 Ancona, Italy
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Kalischuk M, Paret ML, Freeman JH, Raj D, Da Silva S, Eubanks S, Wiggins DJ, Lollar M, Marois JJ, Mellinger HC, Das J. An Improved Crop Scouting Technique Incorporating Unmanned Aerial Vehicle-Assisted Multispectral Crop Imaging into Conventional Scouting Practice for Gummy Stem Blight in Watermelon. PLANT DISEASE 2019; 103:1642-1650. [PMID: 31082305 DOI: 10.1094/pdis-08-18-1373-re] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Multispectral imaging is increasingly used in specialty crops, but its benefits in assessment of disease severity and improvements in conventional scouting practice are unknown. Multispectral imaging was conducted using an unmanned aerial vehicle (UAV), and data were analyzed for five flights from Florida and Georgia commercial watermelon fields in 2017. The fields were rated for disease incidence and severity by extension agents and plant pathologists at randomized locations (i.e., conventional scouting) followed by ratings at locations that were identified by differences in normalized difference vegetation index (NDVI) and stress index (i.e., UAV-assisted scouting). Diseases identified by the scouts included gummy stem blight, anthracnose, Fusarium wilt, Phytophthora fruit rot, Alternaria leaf spot, and cucurbit leaf crumple disease. Disease incidence and severity ratings were significantly different between conventional and UAV-assisted scouting (P < 0.01, Bhapkar/exact test). Higher severity ratings of 4 and 5 on a scale of 1 to 5 from no disease to complete loss of the canopy were more consistent after the scouts used the multispectral images in determining sampling locations. The UAV-assisted scouting locations had significantly lower green, red, and red edge NDVI values and higher stress index values than the conventional scouting areas (P < 0.05, ANOVA/Tukey), and this corresponded to areas with higher disease severity. Conventional scouting involving human evaluation remains necessary for disease validation. Multispectral imagery improved watermelon field scouting owing to increased ability to identify disease foci and areas of concern more rapidly than conventional scouting practices with early detection of diseases 20% more often using UAV-assisted scouting.
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Affiliation(s)
- Melanie Kalischuk
- 1 North Florida Research and Education Center, University of Florida-Institute of Food and Agricultural Sciences (UF-IFAS), Quincy, FL, 32351
| | - Mathews L Paret
- 1 North Florida Research and Education Center, University of Florida-Institute of Food and Agricultural Sciences (UF-IFAS), Quincy, FL, 32351
- 2 Plant Pathology Department, UF-IFAS, Gainesville, FL, 32611
| | - Joshua H Freeman
- 1 North Florida Research and Education Center, University of Florida-Institute of Food and Agricultural Sciences (UF-IFAS), Quincy, FL, 32351
- 3 Horticultural Sciences Department, UF-IFAS, Gainesville, FL, 32611
| | | | - Susannah Da Silva
- 1 North Florida Research and Education Center, University of Florida-Institute of Food and Agricultural Sciences (UF-IFAS), Quincy, FL, 32351
| | - Shep Eubanks
- 5 Gadsden County Extension, UF-IFAS Cooperative Extension Service, Quincy, FL, 32351
| | - D J Wiggins
- 5 Gadsden County Extension, UF-IFAS Cooperative Extension Service, Quincy, FL, 32351
| | - Matthew Lollar
- 6 Jackson County Extension, UF-IFAS Cooperative Extension Service, Marianna, FL, 32448
| | | | | | - Jnaneshwar Das
- 8 School of Earth and Space Exploration, Arizona State University, Tempe, AZ, 85287
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9
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Rennberger G, Gerard P, Keinath AP. Factors Influencing the Occurrence of Foliar Pathogens in Commercial Watermelon Fields in South Carolina Based on Stratified Cluster Sampling. PLANT DISEASE 2019; 103:484-494. [PMID: 30632469 DOI: 10.1094/pdis-07-18-1188-re] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The influence of environmental and management factors on the occurrence of foliar pathogens of watermelon was analyzed using survey-sampling data collected from commercial farms in South Carolina in spring 2015 and spring and fall 2016. A stratified two-stage cluster sampling design was used to sample symptomatic watermelon leaves from 56 fields of 27 growers in seven counties representing the main watermelon-producing areas in the state. In the sampling design, counties corresponded to strata, growers to first-stage clusters, and fields to second-stage clusters. Pathogens were identified on 100 leaves collected per field based on reproductive structures that formed on the leaves. Information about previous crops, fruit type, field size, transplanting date, first harvest date, and fungicides applied within 7 days and within 7 to 14 days prior to sampling was obtained from growers. Field alignment was determined with a compass. Survey-specific logistic regression procedures were used to analyze the effect of these factors on the probabilities of pathogen occurrence. Five fungal pathogens, Stagonosporopsis spp., Podosphaera xanthii, Cercospora citrullina, Colletotrichum orbiculare, and Myrothecium sensu lato (s.l.), and the oomycete Pseudoperonospora cubensis were included in the analyses. Among the factors we analyzed, there was a consistent increased probability of occurrence of Stagonosporopsis spp. in fields with a previous cucurbit crop, increasing probabilities of pathogen occurrence with increasing plant age, a lower probability of occurrence of some pathogens on triploid cultivars compared with diploid cultivars, and a decrease in probability of pathogen occurrence in fields aligned toward southwest or west. Application of fungicides significantly reduced the probability of observing C. citrullina, P. cubensis, and Stagonosporopsis spp. in 2015 and P. xanthii in spring 2016. This study emphasizes the importance of crop rotation and fungicide applications to manage foliar diseases of watermelon, particularly gummy stem blight, powdery mildew, and downy mildew. Crop age, cultivar type, and field alignment also were found to significantly influence the probability of pathogen occurrence. To the best of our knowledge, this is the first study examining the influence of various factors on foliar pathogens of watermelon with data collected from commercial fields.
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Affiliation(s)
- Gabriel Rennberger
- 1 Clemson University, Coastal Research and Education Center, Charleston, SC 29414; and
| | - Patrick Gerard
- 2 Clemson University, Department of Mathematical Sciences, Clemson, SC 29634
| | - Anthony P Keinath
- 1 Clemson University, Coastal Research and Education Center, Charleston, SC 29414; and
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