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Abiodun Ajulo A, Asobia PC, Silva de Oliveira R, de Andrade Bezerra G, Rosa Gonçalves A, de Filippi MCC. Screening bacterial isolates for biocontrol of sheath blight in rice plants. J Environ Sci Health B 2023; 58:426-435. [PMID: 37313602 DOI: 10.1080/03601234.2023.2220644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Sheath blight (Rhizoctonia solani) causes significant yield losses in rice (Oryza sativa L.). Its sustainable management needs an efficient biocontrol agent. The objective was to screen bacterial isolates as an antagonist to R. solani and identify the most efficient ones as sheath blight suppressors under greenhouse conditions. Two assays (E1 and E2) were performed in a completely randomized design with three replications. E1 tested 21 bacterial isolates antagonists to R. solani in vitro. E2 was conducted under greenhouse conditions, with rice cultivar BRS Pampeira sown in plastic pots (7 kg) containing fertilized soil. Sixty old plants were inoculated with a segment of a toothpick containing fragments of R. solani, followed by spray inoculation of a bacterial suspension (108 CFU/mL). The severity of the disease was determined by calculating the relative lesion size formed on the colm. Isolates BRM32112 (Pseudomonas nitroreducens), BRM65929 (Priestia megaterium), and BRM65919 (Bacillus cereus) reduced R. solani colony radial growth by 92.8, 77.56, and 75.56%, respectively while BRM63523 (Serratia marcescens), BRM65923 and BRM65916 (P. megaterium) and BRM65919 (B. cereus) with 23.45, 23.37, 23.62, and 20.17 cm, respectively were effective at suppressing sheath blight in greenhouse, indicating their potential as a biofungicide for sheath blight suppression.
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Affiliation(s)
- Akintunde Abiodun Ajulo
- Plant Pathology and Agricultural Microbiology Laboratory at Embrapa Rice and Beans, Santo Antônio de Goiás, Goiás state, Brazil
- Graduate Program in Agronomy, Federal University of Goiás, Goiânia, Goiás state, Brazil
| | | | | | | | - Ariany Rosa Gonçalves
- Plant Pathology and Agricultural Microbiology Laboratory at Embrapa Rice and Beans, Santo Antônio de Goiás, Goiás state, Brazil
| | - Marta Cristina Corsi de Filippi
- Plant Pathology and Agricultural Microbiology Laboratory at Embrapa Rice and Beans, Santo Antônio de Goiás, Goiás state, Brazil
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Arriel-Elias MT, Pereira AK, Arriel GCTF, Alexandre G, de Andrade Bezerra G, Fill TP, Severino VGP, de Filippi MCC. Molecular networking as a tool to annotate the metabolites of Bacillus sp. and Serratia marcescens isolates and evaluate their fungicidal effects against Magnapothe oryzae and Bipolaris oryzae. 3 Biotech 2023; 13:148. [PMID: 37128476 PMCID: PMC10147858 DOI: 10.1007/s13205-023-03547-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 03/28/2023] [Indexed: 05/03/2023] Open
Abstract
Rhizobacteria are valuable sources of compounds that can be used for the integrated management of diseases in rice. Here, we aimed to explore the metabolism and organize and annotate the metabolites of Bacillus sp. and Serratia marcescens isolates using molecular networking and evaluate their fungicidal effects against Magnaporthe oryzae and Bipolaris oryzae. We obtained bacterial extracts after 6 and 16-h incubation via liquid-liquid extraction using ethyl acetate as solvent. We performed UHPLC-MS analysis and data processing using molecular networking and conducted biological assays in rice plants. Using the Global Natural Product Social spectral libraries, we annotated the following compounds: austinoneol, Phe-Pro, N-acetyl-l-leucine, Leu-Gly, Ile-Leu, Phe-Pro, 2,5-piperazinedione, 3-(1H-indol-3-methyl)-6-methyl-cyclo(d-Trp-l-Pro), and cholic acid. Results of the biological assays showed that the bacterial extracts reduced the mycelial growth of both pathogens in all treatments compared to the control. In the greenhouse setup, 8 days after the challenge for leaf gray spot and leaf blast, all treatments affected up to 4.4% of the leaf area, with an area under disease progress curve of 13.24, showing significant difference compared to the control, which affected 23% of the leaf area, with an AUDPC of 44.65. Our study provides potential new sources of natural products to be applied in the integrated management of rice. Supplementary Information The online version contains supplementary material available at 10.1007/s13205-023-03547-6.
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Affiliation(s)
| | - Alana Kelyene Pereira
- Department of Organic Chemistry, Institute of Chemistry, Universidade Estadual de Campinas, Campinas, Brazil
| | | | - Gerso Alexandre
- Institute of Chemistry, Universidade Federal de Goiás, Goiânia, Brazil
| | | | - Taícia Pacheco Fill
- Department of Organic Chemistry, Institute of Chemistry, Universidade Estadual de Campinas, Campinas, Brazil
| | | | - Marta Cristina Corsi de Filippi
- Phytopathology Laboratory (Laboratório de Fitopatologia), Brazilian Enterprise for Agricultural Research-Rice and Beans (Embrapa Arroz E Feijão), Goiânia, GO 75375-000 Brazil
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Abstract
Pyricularia oryzae is the etiological agent of rice blast, the most destructive disease in rice crops and chemical control based on fungicide is the main method used in its management. The aim of this study was characterize pathogenicity and identify P. oryzae isolates adapted to tricyclazole. P. oryzae monosporic isolates were collected in the state of Tocantins and inoculated in international differentiating series of rice cultivars for determination of pathotypes. After, the same isolates were inoculated in the rice cultivar IRGA 424 to evaluate resistance to fungicide Bim® 750 BR (Tricyclazole - 250 g/ha) that was applied 24 and 48 hours after pathogen inoculation (hai). Leaf blast severity and infection efficiency were evaluated 9 days after inoculation (dai), latency period (2 dai) and sporulation intensity (7 dai). Nine different pathotypes were identified, predominantly as IA group. The latent period of isolates occurred between from 48 to 120 h. The application of tricyclazole, 24 hai reduced disease severity with the exception of the isolate Py 7.1. The great variability of the pathogen allowed for adaptation to this molecule and can increase its aggressiveness and should be considered to guide the integrated management of the disease.
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Affiliation(s)
| | | | | | - Eduardo Seiti Gomide Mizubuti
- Phytopathogen Population Biology Laboratory - BioPop, Department of Phytopathology, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
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de Sousa TP, Chaibub AA, Cortes MVDCB, Batista TFC, Bezerra GDA, da Silva GB, de Filippi MCC. Molecular identification of Trichoderma sp. isolates and biochemical characterization of antagonistic interaction against rice blast. Arch Microbiol 2021; 203:3257-3268. [PMID: 33837802 DOI: 10.1007/s00203-021-02307-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 03/17/2021] [Accepted: 03/24/2021] [Indexed: 10/21/2022]
Abstract
This study aimed to identify four isolates of Trichoderma sp. (Ufra.T06, Ufra.T09, Ufra.T12, and Ufra.T52) and characterize their interaction with Magnaporthe oryzae in vitro and in vivo conditions. The four isolates of Trichoderma sp. were sequenced, investigated as an antagonist against M. oryzae in five Petri plate assays, and as an inhibitor of conidial germination appressoria formation. Finally, were quantified the lytic activity of chitinase (CHI), glucanase (GLU), and protease (PRO) during co-cultivation of Trichoderma sp. and M. oryzae. In vivo, leaf blast suppression was evaluated in two assays: simultaneous and curative application. Both in vitro and in vivo assays were scanned by electron microscopy (SEM). All isolates were identified as Trichoderma asperellum. All in vitro Petri plates assays reduced M. oryzae colony growth (paired-91.18% by Ufra.T09, volatile metabolites-all isolates equally reduced, non-volatile-68.33% by Ufra.T06, thermostability-99.77% by Ufra.T52 and co-cultivate-64.25% by Ufra.T52). The filtrates and conidia suspensions for T. asperellum isolates inhibited the conidia germination and appressoria formation significantly. In co-cultivate (mycelial or cell wall), all enzymes (GLU, CHI, and PRO) and times (24, 48, and 72 h) showed increased activity. In vivo, reduced leaf blast severity until 94.64% (Ufra.T52cs) in a simultaneous and until 85% (Ufra.T09 24 and 48 hasi) in a curative application. T. asperellum isolates showed efficient control of M. oryzae by mycoparasitism, and antibiosis mechanisms were interfered with by the M. oryzae infection process.
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Affiliation(s)
| | | | | | - Telma Fátima Coelho Batista
- Plant Protection Laboratory, Institute of Agrarian Sciences, Federal Rural University of Amazonia., Campus Belém, Pará, Brazil
| | | | - Gisele Barata da Silva
- Plant Protection Laboratory, Institute of Agrarian Sciences, Federal Rural University of Amazonia., Campus Belém, Pará, Brazil
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Sperandio EM, Alves TM, Vale HMMD, Gonçalves LDA, Silva ECE, Filippi MCCD. Signaling defense responses of upland rice to avirulent and virulent strains of Magnaporthe oryzae. J Plant Physiol 2020; 253:153271. [PMID: 32927133 DOI: 10.1016/j.jplph.2020.153271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 08/24/2020] [Accepted: 08/24/2020] [Indexed: 06/11/2023]
Abstract
Rice blast (Magnaporthe oryzae) can cause large losses in crop yields, especially in upland rice systems. Avirulent strains of M. oryzae can induce resistance to subsequent attacks by virulent strains in plants. This study aimed to investigate the defense responses in upland rice challenged with a virulent strain of M. oryzae after acclimation with an avirulent strain. The avirulent strain decreased rice blast severity in the challenged plants. Induced resistance was characterized by a hypersensitive response and early accumulation of phenolic compounds. Scanning electron microscopy showed that M. oryzae conidia germinate and form appressoria, but do not colonize leaf tissues. The activities of pathogenesis-related proteins, total phenolic compounds, and salicylic acid (SA) were affected by acclimation to the avirulent strain. The activities of β-1,3-glucanase, phenylalanine ammonia-lyase, and peroxidase, as well as the SA levels explained most of the variability in the rice plant responses to M. oryzae. In addition, OsXa13, OsMAPKKK74, OsAOS2, OsACO7, and OsMAS1 expression was modulated depending on the virulence of the M. oryzae strains. This modulation in gene expression is critical for infection and some of these mechanisms are targeted by effectors, resulting in enhanced susceptibility and pathogen infection. These results have practical importance in plant-pathogen interaction studies to identify resistance-relevant mechanisms against M. oryzae in upland rice.
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Affiliation(s)
- Eugenio M Sperandio
- Polo de Inovação, Instituto Federal Goiano, Rodovia Sul Goiana Km 01, Rio Verde, GO, 75901-000, Brazil.
| | - Tavvs Micael Alves
- Polo de Inovação, Instituto Federal Goiano, Rodovia Sul Goiana Km 01, Rio Verde, GO, 75901-000, Brazil.
| | - Helson Mário Martins do Vale
- Departamento de Fitopatologia, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, Distrito Federal, 70910-900, Brazil.
| | - Letícia de Almeida Gonçalves
- Departamento de Botânica, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Av. Esperança s/n, Campus Samambaia, Goiânia, GO, 74690-900, Brazil.
| | - Elienai Candia E Silva
- Programa de Pós-graduação em Botânica, Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Av. Peter Henry Rolfs, s/n - Campus Universitário, Viçosa, MG, 36570-900, Brazil.
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Arriel-Elias MT, de Carvalho Barros Côrtes MV, de Sousa TP, Chaibub AA, de Filippi MCC. Induction of resistance in rice plants using bioproducts produced from Burkholderia pyrrocinia BRM 32113. Environ Sci Pollut Res Int 2019; 26:19705-19718. [PMID: 31089999 DOI: 10.1007/s11356-019-05238-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 04/22/2019] [Indexed: 06/09/2023]
Abstract
Leaf blast is the main rice disease in the world causing significant losses in productivity. Blast integrate management (BIM) requires the use of genetic resistance, cultural practices, and chemical control, although for sustainable BIM, the insertion of biological agents may be the fourth component for. The objective of this work was to test three formulations of Burkholderia pyrrocinia (BRM32113) previously selected and to verify the effectiveness in resistance induction and blast control in rice. Two experiments were carried out, in a completely randomized design with three replications, in the greenhouse (E1 and E2). E1 aimed to select the best treatment for suppressing leaf blast severity and activating plant defense mechanisms. It was composed of 8 treatments: (1) formulated 11+ B. pyrrocina × Magnaporthe oryzae; (2) formulated 17+ B. pyrrocina × M. oryzae; (3) formulated 32+ B. pyrrocina × M. oryzae; (4) formulated 11 × M. oryzae; (5) B. pyrrocinia 17 × M. oryzae; (6) formulated 32 × M. oryzae; (7) B. pyrrocina × M. oryzae; (8) M. oryzae; (9) control (water). E2 aimed to investigate the effect of the best treatments, for the promotion of plant growth and suppression of leaf blast by calculating AUDPC. It was composed of 6 treatments: (1) formulated 11+ B. pyrrocina × M. oryzae; (2) formulated 32+ B. pyrrocina × M. oryzae; (3) formulated 11 × M. oryzae; (4) formulated 32 × M. oryzae; (5) B. pyrrocina × M. oryzae; (6) water. And after, we did two assays aimed to localize this biological agent after application at seed, soil, and rice plant. In E1, formulated 11+ B. pyrrocinia and 32+ formulated and B. pyrrocina were the best, suppressing leaf blast by up to 97% and providing the significant increase of the enzymes β-1,3-glucanase, chitinase, phenylalanine ammonia lyase, lipoxygenase, and salicylic acid at 24 h and 48 h after inoculation with M. oryzae. In E2, treatments formulated 11+ B. pyrrocinia, formulated 32+ B. pyrrocinia, and B. pyrrocina provided more significant increases in growth promotion and reduced area under disease progress curve. B. pyrrocinia was detected in the rice plant for 18 days, predominantly in the root system (internal and external). The use of B. pyrrocinia formulations based on sugarcane molasses and glycerol can be an essential strategy for sustainable management. Although all the benefits come from these sustainable formulations, the adoption by commercial biological segment depends on an established formulation process. It seems that all the results showed here by this research will be readily assimilated by startups of the organic segment.
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Affiliation(s)
| | - Marcio Vinicius de Carvalho Barros Côrtes
- Phytopathology Laboratory (Laboratório de Fitopatologia), Brazilian Enterprise for Agricultural Research-Rice and Beans (Embrapa Arroz e Feijão), Goiânia, GO, 75375-000, Brazil
| | | | | | - Marta Cristina Corsi de Filippi
- Phytopathology Laboratory (Laboratório de Fitopatologia), Brazilian Enterprise for Agricultural Research-Rice and Beans (Embrapa Arroz e Feijão), Goiânia, GO, 75375-000, Brazil.
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de Sousa TP, de Souza ACA, de Filippi MCC, Lanna AC, Cortês MV, Pinheiro HA, da Silva GB. Bioagents and silicon promoting fast early upland rice growth. Environ Sci Pollut Res 2018; 25:3657-3668. [PMID: 0 DOI: 10.1007/s11356-017-0753-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 11/14/2017] [Indexed: 05/26/2023]
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Nascente AS, de Filippi MCC, Lanna AC, de Sousa TP, de Souza ACA, da Silva Lobo VL, da Silva GB. Effects of beneficial microorganisms on lowland rice development. Environ Sci Pollut Res Int 2017; 24:25233-25242. [PMID: 28929284 DOI: 10.1007/s11356-017-0212-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 09/13/2017] [Indexed: 06/07/2023]
Abstract
Microorganisms can promote plant growth by increasing phytomass production, nutrient uptake, photosynthesis rates, and grain yield, which can result in higher profits for farmers. However, there is limited information available about the physiological characteristics of lowland rice after treatment with beneficial microorganisms in the tropical region. This study aimed to determine the effects of different beneficial microorganisms and various application forms on phytomass production, gas exchange, and nutrient contents in the lowland rice cultivar 'BRS Catiana' in a tropical region. The experiment was performed under greenhouse conditions utilizing a completely randomized design and a 7 × 3 + 1 factorial scheme with four replications. The treatments consisted of seven microorganisms, including the rhizobacterial isolates BRM 32113, BRM 32111, BRM 32114, BRM 32112, BRM 32109, and BRM 32110 and Trichoderma asperellum pooled isolates UFRA-06, UFRA-09, UFRA-12, and UFRA-52, which were applied using three different methods (microbiolized seed, microbiolized seed + soil drenched with a microorganism suspension at 7 and 15 days after sowing (DAS), and microbiolized seed + plant spraying with a microorganism suspension at 7 and 15 DAS) with a control (water). The use of microorganisms can provide numerous benefits for rice in terms of crop growth and development. The microorganism types and methods of application positively and differentially affected the physiological characteristics evaluated in the experimental lowland rice plants. Notably, the plants treated with the bioagent BRM 32109 on the seeds and on seeds + soil produced plants with the highest dry matter biomass, gas exchange rate, and N, P, Fe, and Mg uptake. Therefore, our findings indicate strong potential for the use of microorganisms in lowland rice cultivation systems in tropical regions. Currently, an additional field experiment is in its second year to validate the beneficial result reported here and the novel input sustainability.
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Affiliation(s)
- Adriano Stephan Nascente
- Embrapa Arroz e Feijão, Rodovia GO-462, Km 12, Fazenda Capivara, Zona Rural, Caixa Postal: 179, Santo Antônio de Goiás, Goiás, CEP 75375-000, Brazil.
| | - Marta Cristina Corsi de Filippi
- Embrapa Arroz e Feijão, Rodovia GO-462, Km 12, Fazenda Capivara, Zona Rural, Caixa Postal: 179, Santo Antônio de Goiás, Goiás, CEP 75375-000, Brazil
| | - Anna Cristina Lanna
- Embrapa Arroz e Feijão, Rodovia GO-462, Km 12, Fazenda Capivara, Zona Rural, Caixa Postal: 179, Santo Antônio de Goiás, Goiás, CEP 75375-000, Brazil
| | | | - Alan Carlos Alves de Souza
- Lavras Federal University, Avenida Doutor Sylvio Menicucci, 1001, Lavras, Minas Gerais, CEP 37200-000, Brazil
| | - Valácia Lemes da Silva Lobo
- Embrapa Arroz e Feijão, Rodovia GO-462, Km 12, Fazenda Capivara, Zona Rural, Caixa Postal: 179, Santo Antônio de Goiás, Goiás, CEP 75375-000, Brazil
| | - Gisele Barata da Silva
- Plant Protection Laboratory, Institute of Agrarian Sciences, Federal Rural University of Amazon, Belém, Pará, Brazil
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Nascente AS, de Filippi MCC, Lanna AC, de Souza ACA, da Silva Lobo VL, da Silva GB. Biomass, gas exchange, and nutrient contents in upland rice plants affected by application forms of microorganism growth promoters. Environ Sci Pollut Res Int 2017; 24:2956-2965. [PMID: 27844322 DOI: 10.1007/s11356-016-8013-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 10/28/2016] [Indexed: 06/06/2023]
Abstract
Microorganisms are considered a genetic resource with great potential for achieving sustainable development of agricultural areas. The objective of this research was to determine the effect of microorganism application forms on the production of biomass, gas exchange, and nutrient content in upland rice. The experiment was conducted under greenhouse conditions in a completely randomized design in a factorial 7 × 3 + 1, with four replications. The treatments consisted of combining seven microorganisms with three application forms (microbiolized seed; microbiolized seed + soil drenched with a microorganism suspension at 7 and 15 days after sowing (DAS); and microbiolized seed + plant sprayed with a microorganism suspension at 7 and 15 DAS) and a control (water). Treatments with Serratia sp. (BRM32114), Bacillus sp. (BRM32110 and BRM32109), and Trichoderma asperellum pool provided, on average, the highest photosynthetic rate values and dry matter biomass of rice shoots. Plants treated with Burkolderia sp. (BRM32113), Serratia sp. (BRM32114), and Pseudomonas sp. (BRM32111 and BRM32112) led to the greatest nutrient uptake by rice shoots. Serratia sp. (BRM 32114) was the most effective for promoting an increase in the photosynthetic rate, and for the greatest accumulation of nutrients and dry matter at 84 DAS, in rice shoots, which differed from the control treatment. The use of microorganisms can bring numerous benefits of rice, such as improving physiological characteristics, nutrient uptake, biomass production, and grain yield.
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Affiliation(s)
- Adriano Stephan Nascente
- Embrapa Arroz e Feijão, Rodovia GO-462, Km 12, PO Box 179, Santo Antônio de Goiás, GO, CEP 75375-000, Brazil.
| | | | - Anna Cristina Lanna
- Embrapa Arroz e Feijão, Rodovia GO-462, Km 12, PO Box 179, Santo Antônio de Goiás, GO, CEP 75375-000, Brazil
| | - Alan Carlos Alves de Souza
- Embrapa Arroz e Feijão, Rodovia GO-462, Km 12, PO Box 179, Santo Antônio de Goiás, GO, CEP 75375-000, Brazil
| | - Valácia Lemes da Silva Lobo
- Embrapa Arroz e Feijão, Rodovia GO-462, Km 12, PO Box 179, Santo Antônio de Goiás, GO, CEP 75375-000, Brazil
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Chaibub AA, de Carvalho JCB, de Sousa Silva C, Collevatti RG, Gonçalves FJ, de Carvalho Barros Côrtes MV, de Filippi MCC, de Faria FP, Lopes DCB, de Araújo LG. Defence responses in rice plants in prior and simultaneous applications of Cladosporium sp. during leaf blast suppression. Environ Sci Pollut Res Int 2016; 23:21554-21564. [PMID: 27515526 DOI: 10.1007/s11356-016-7379-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 08/02/2016] [Indexed: 06/06/2023]
Abstract
An alternative method to control rice blast (Magnaporthe oryzae) is to include biological agent in the disease management strategy. The objective of this study was to assess the leaf blast-suppressing effects of rice phylloplane fungi. One Cladosporium sp. phylloplane fungus was shown to possess biocontrolling traits based on its morphological characteristics and an analysis of its 18S ribosomal DNA. Experiments aimed at determining the optimal time to apply the bioagent and the mechanisms involved in its rice blast-suppressing activities were performed under controlled greenhouse conditions. We used foliar spraying to apply the Cladosporium sp. 48 h prior to applying the pathogen, and we found that this increased the enzymatic activity. Furthermore, in vitro tests performed using isolate C24 showed that it possessed the ability to secrete endoxylanases and endoglucanases. When Cladosporium sp. was applied either prior to or simultaneous with the pathogen, we observed a significant increase in defence enzyme activity, and rice blast was suppressed by 84.0 and 78.6 %, respectively. However, some enzymes showed higher activity at 24 h while others did so at 48 h after the challenge inoculation. Cladosporium sp. is a biological agent that is capable of suppressing rice leaf blast by activating biochemical defence mechanisms in rice plants. It is highly adapted to natural field conditions and should be included in further studies aimed at developing strategies to support ecologically sustainable disease management and reduce environmental pollution by the judicious use of fungicidal sprays.
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Affiliation(s)
- Amanda Abdallah Chaibub
- Genetics of Microorganism Laboratory, Federal University of Goiás, Rodovia Goiânia/Nova Veneza, km 0. Goiânia, Goiás, 74001-970, Brazil
| | | | - Carlos de Sousa Silva
- Genetics of Microorganism Laboratory, Federal University of Goiás, Rodovia Goiânia/Nova Veneza, km 0. Goiânia, Goiás, 74001-970, Brazil
| | - Rosane Garcia Collevatti
- Genetics and Biodiversity Laboratory, Federal University of Goiás, Rodovia Goiânia/Nova Veneza, Km 0. Goiânia, Goiás, 74001-970, Brazil
| | - Fábio José Gonçalves
- Plant Pathology and Microbiology Laboratory at Embrapa Rice and Beans, Rodovia GO-462, km 12 Zona Rural C.P. 179, Cep, Santo Antônio de Goiás, GO, 75375-000, Brazil
| | - Márcio Vinícius de Carvalho Barros Côrtes
- Plant Pathology and Microbiology Laboratory at Embrapa Rice and Beans, Rodovia GO-462, km 12 Zona Rural C.P. 179, Cep, Santo Antônio de Goiás, GO, 75375-000, Brazil
| | - Marta Cristina Corsi de Filippi
- Plant Pathology and Microbiology Laboratory at Embrapa Rice and Beans, Rodovia GO-462, km 12 Zona Rural C.P. 179, Cep, Santo Antônio de Goiás, GO, 75375-000, Brazil.
| | - Fabrícia Paula de Faria
- Fungi Biotechnology Laboratory, Rodovia Goiânia / Nova Veneza, Km 0. Goiânia, Goiás, 74001-970, Brazil
| | | | - Leila Garcês de Araújo
- Genetics of Microorganism Laboratory, Federal University of Goiás, Rodovia Goiânia/Nova Veneza, km 0. Goiânia, Goiás, 74001-970, Brazil
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