Fitopatologia - Artigos
URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11741
Navegar
7 resultados
Resultados da Pesquisa
Item Efeito da aplicação foliar de silício na resistência à ferrugem e na potencialização da atividade de enzimas de defesa em cafeeiro(Tropical Plant Pathology, 2009-07) Rodrigues, Fabrício A.; Carré-Missio, Vivian; Oliveira, Maria Goreti A.; Pereira, Sandra C.; Zambolim, LaércioA principal medida de controle da ferrugem do cafeeiro, causada por Hemileia vastatrix, é o uso de fungicidas. O fornecimento de silício (Si) às plantas é uma estratégia de controle interessante considerando o potencial desse elemento em aumentar a resistência de várias espécies de plantas à patógenos. Este trabalho avaliou o efeito da aplicação foliar do Si na redução da severidade da ferrugem e na possível potencialização da atividade de seis enzimas relacionadas com a resistência de plantas à patógenos. Mudas de café (cultivar Catuaí Vermelho 44) foram pulverizadas com água destilada, solução de silicato de potássio (KSi) (35 g/L, pH 10,5), KSi (35 g/L, pH 5,5) e solução de acibenzolar-S-metil (ASM) (200 µg/L) 24 horas antes da inoculação. Não houve diferença significativa entre os tratamentos para os teores foliares de Si e potássio. A severidade foi significativamente maior em mudas pulverizadas com água em relação aos demais tratamentos. O ASM reduziu significativamente a severidade em 70% em relação à aplicação de água. A aplicação de soluções de KSi, independente do pH, também reduziu a severidade. O ASM foi eficiente em aumentar a atividade de quitinases e β-1,3-glucanases, porém a aplicação de KSi, independente do pH da solução, foi ineficiente em potencializar a atividade das seis enzimas estudadas, embora tenha reduzido a severidade.Item Herança da resistência do Híbrido de Timor UFV 443-03 à ferrugem- do- cafeeiro(Pesquisa Agropecuária Brasileira, 2009-03) Capucho, Alexandre Sandri; Caixeta, Eveline Teixeira; Zambolim, Eunize Maciel; Zambolim, LaércioO objetivo deste trabalho foi caracterizar a herança da resistência do Híbrido de Timor UFV 443-03 à ferrugem-do-cafeeiro (Hemileia vastatrix). Para isso, a raça II e o patótipo 001 de ferrugem foram inoculados em 246 plantas da população F2, 115 plantas do retrocruzamento suscetível (RCS) e 87 plantas do retrocruzamento resistente (RCR), originadas do cruzamento entre o genótipo suscetível cv. Catuaí Amarelo IAC 64 e a fonte de resistência Híbrido de Timor UFV 443-03. Para ambos os inóculos, a cv. Catuaí Amarelo IAC 64 foi suscetível, enquanto o Híbrido de Timor UFV 443-03, a planta representante da geração F1 e as plantas do RCR foram resistentes. As plantas F2, quando inoculadas com a raça II, apresentaram dois padrões de segregação significativos: 15:1 e 61:3. A herança da resistência foi confirmada pela inoculação das plantas do RCS, que segregaram na proporção de 3:1, padrão esperado para herança condicionada por dois genes. A hipótese de segregação 7:1 para três genes foi rejeitada. Resultados semelhantes foram obtidos para o patótipo 001. Dois genes dominantes e independentes conferem a resistência genética do Híbrido de Timor UFV 443-03 à raça II e ao patótipo 001 de H. vastatrix.Item DMI and QoI fungicides for the control of coffee leaf rust(Australasian Plant Pathology, 2015-09) Zambolim, Laércio; Lopes, Uilton do Nascimento; Lopes, Ueder Pedro; Honorato Jr., Jaime; Duarte, Henrique da Silva SilveiraThis study investigated the ability of different triazole and strobilurin fungicides either alone or combination when applied to the leaves and triazole to the soil for control of Coffee Leaf Rust (CLR). The experiments were performed in a greenhouse using three month-old coffee seedlings, and in the field with five years old plants using the susceptible variety ‘Catuai vermelho’, at elevation of 750 m, from 2010 to 2012, in Viçosa, Minas Gerais State, Brazil. The effects of triazole (triadimenol, cyproconazole and epoxiconazole) and strobilurin (azoxystrobin, trifloxystrobin, pyraclostrobin) was first studied in a greenhouse to evaluate the translaminar effect on CLR control. Based on the results obtained in the greenhouse, a field experiment was performed to evaluate the effect of triazole applied to the soil and triazole + strobilurin sprayed on CLR control and the effect on coffee berry yield of the plants. The different fungicides applied in the greenhouse reduced CLR severity by 8.9 % (trifloxystrobin), 79.4 % (azoxystrobin), 82.0 % (triadimenol), 93.2 % (cyproconazole), 96.6 % (epoxiconazole) and 98.5 % (pyraclostrobin) compared to that in the control plants. In the field experiment triazole + strobilurin fungicides provided effective CLR control. The co-application of epoxiconazole and pyraclostrobin or azoxystrobin sprayed twice resulted in the most effective CLR control and maintained the highest coffee berry yield. The incidence of CLR was 83.5, 54.0 and 78.5 % for the control treatments, whereas the incidence did not exceeded 24.4, 37.0 and 39.0 % on the sprayed plants. The average coffee berry yield increased by 33.9 % (lowest value) when applying triadimenol to the soil in November followed by cyproconazole + trifloxystrobin sprayed in December and February, and increased by 99.1 % (highest value) in the treatment with epoxiconazol + pyraclostrobin sprayed in December and March compared with plants that did not receive any fungicide application. The control treatment and that of triadimenol applied to the soil in November followed by cyproconazole + trifloxystrobin sprayed in December and February yielded less than 1800 (1320 to 1800) kg/ha of processed coffee, whereas the other treatments more than 2100 (2142 to 2676) kg/ha. Treatments with cyproconazole applied to the soil in November followed by cyproconazole + azoxystrobin sprayed on the leaves in December and February, epoxiconazol + pyraclostrobin sprayed on the leaves in December and March, and cyproconazole + azoxystrobin sprayed on leaves in December, February and April yielded more than 2340 (2340 to 2676) kg/ha of processed coffee. This is the first report indicating that a triazole fungicide applied to the soil and triazole + strobilurin fungicide sprayed on the leaves, efficiently controlled CLR and significantly increased coffee berry yield for three seasons.Item Biological control of coffee rust by antagonistic bacteria under field conditions in Brazil(Biological Control, 2009-02-13) Haddad, Fernando; Maffia, Luiz A.; Mizubuti, Eduardo S. G.; Teixeira, HudsonRust (Hemileia vastatrix) is the most important coffee disease in Brazil. Organic coffee production has increased in the country and a research program aimed to develop alternatives to chemicals for disease control was required. Seven bacterial isolates, isolated from organic coffee plantings and selected in greenhouse tests, were evaluated under commercial organic crop conditions in 2005 (Experiment 1) and 2005/2006 (Experiment 2), in Machado, MG, Brazil. Ten treatments consisting of the seven bacterial isolates, copper hydroxide, calcium silicate and water were applied as three or four monthly sprays in Experiment 1 or 2, respectively. Rust severity and incidence were evaluated monthly. In Experiment 1, the sprays started in January when rust incidence was 23.8%, and none of the treatments reduced rust progress significantly. In Experiment 2, the sprays began in November 2005, when rust incidence was approximately 7.5%. There were significant differences (P < 0.0001) between treatments regarding maximum incidence and severity (as assessed in June, 2006), the rate of increase of the incidence between November 2005 and June 2006 and for the areas under disease progress curves for both rust incidence and severity. Lower values for these treatments were obtained in the plots treated with copper hydroxide or Bacillus sp. isolate B157, and intermediate values with the Pseudomonas sp. isolate P286. In a third experiment conducted in 2007 in Ervália, MG, isolates B157 and P286 were also evaluated; isolate B157 reduced rust intensity as effectively as copper hydroxide. Isolate B157 is considered a potential biocontrol agent for coffee rust for organic crop systems in Brazil.Item Marker-assisted selection provides arabica coffee with genes from other Coffea species targeting on multiple resistance to rust and coffee berry disease(Molecular Breeding, 2017-01-04) Alkimim, Emilly Ruas; Caixeta, Eveline Teixeira; Sousa, Tiago Vieira; Pereira, Antônio Alves; Oliveira, Antonio Carlos Baião de; Zambolim, Laércio; Sakiyama, Ney SussumuSelecting superior genotypes is facilitated by marker-assisted selection (MAS), which is particularly suitable for transferring disease resistance alleles because it nullifies environmental effects and allows selection of resistant individuals in the absence of the pathogen or race, enabling preventive breeding. Molecular markers linked to two major genes (SH3 and SH?), conferring resistance to coffee rust, and those linked to the Ck-1 gene, conferring resistance to coffee berry disease (CBD), have previously been identified. These markers were validated and used in a progeny of crosses between Indian selections with Coffea arabica cultivars. Eleven resistant individuals homozygous for SH3 were identified by MAS. Of these, seven carry SH? from Híbrido de Timor and the gene introduced from Coffea liberica (SH3). SH? was characterized as derived from Coffea canephora. Thus, it was possible to identify C. arabica genotypes carrying important genes for rust resistance introgressed from other coffee species. MAS also allowed identification of sources of CBD resistance for use in preventive breeding for resistance to this serious disease. Using two validated molecular markers, two coffee plants carrying Ck-1 were identified: the UFV 328-60 genotype (F2) was resistant and homozygous based on both molecular markers but exhibited no markers related to SH3 and SH?, and the UFV 317-12 genotype (F1) was resistant and homozygous but resistant and heterozygous based on CBD-Sat207 and CBD-Sat235, respectively. Along with possessing Ck-1, the latter carries SH?. Overall, plants carrying different genes for resistance to rust and CBD were identified. These plants are important sources for gene pyramiding in breeding programs aimed at multiple and durable resistance.Item The Hemileia vastatrix effector HvEC‐016 suppresses bacterial blight symptoms in coffee genotypes with the SH1 rust resistance gene(New Phytologist, 2016-12-05) Maia, Thiago; Badel, Jorge L.; Marin‐Ramirez, Gustavo; Rocha, Cynthia de M.; Fernandes, Michelle B.; Silva, José C. F. da; Azevedo‐Junior, Gilson M. de; Brommonschenkel, Sérgio H.A number of genes that confer resistance to coffee leaf rust (SH1–SH9) have been identified within the genus Coffea, but despite many years of research on this pathosystem, the complementary avirulence genes of Hemileia vastatrix have not been reported. After identification of H. vastatrix effector candidate genes (HvECs) expressed at different stages of its lifecycle, we established an assay to characterize HvEC proteins by delivering them into coffee cells via the type‐three secretion system (T3SS) of Pseudomonas syringae pv. Garcae (Psgc). Employing a calmodulin‐dependent adenylate cyclase assay, we demonstrate thatPsgc recognizes a heterologous P. syringae T3SS secretion signal which enables us to translocate HvECs into the cytoplasm of coffee cells. Using this Psgc‐adapted effector detector vector (EDV) system, we found that HvEC‐016 suppresses the growth of Psgcon coffee genotypes with the SH1 resistance gene. Suppression of bacterial blight symptoms in SH1 plants was associated with reduced bacterial multiplication. By contrast, HvEC‐016 enhanced bacterial multiplication in SH1‐lacking plants. Our findings suggest that HvEC‐016 may be recognized by the plant immune system in a SH1‐dependent manner. Thus, our experimental approach is an effective tool for the characterization of effector/avirulence proteins of this important pathogen.Item The Hemileia vastatrix effector HvEC-016 suppresses bacterial blight symptoms in coffee genotypes with the S H 1 rust resistance gene(New Phytologist, 2016-10-16) Maia, Thiago; Badel, Jorge L.; Marin-Ramirez, Gustavo; Rocha, Cynthia de M.; Fernandes, Michelle B.; Silva, José C. F. da; Azevedo-Junior, Gilson M. de; Brommonschenkel, Sérgio H.A number of genes that confer resistance to coffee leaf rust (S H 1–S H 9) have been identified within the genus Coffea, but despite many years of research on this pathosystem, the complementary avirulence genes of Hemileia vastatrix have not been reported. After identification of H. vastatrix effector candidate genes (HvECs) expressed at different stages of its lifecycle, we established an assay to characterize HvEC proteins by delivering them into coffee cells via the type-three secretion system (T3SS) of Pseudomonas syringae pv. garcae (Psgc). Employing a calmodulin-dependent adenylate cyclase assay, we demonstrate that Psgc recognizes a heterologous P. syringae T3SS secretion signal which enables us to translocate HvECs into the cytoplasm of coffee cells. Using this Psgc-adapted effector detector vector (EDV) system, we found that HvEC-016 suppresses the growth of Psgc on coffee genotypes with the S H 1 resistance gene. Suppression of bacterial blight symptoms in S H 1 plants was associated with reduced bacterial multiplication. By contrast, HvEC-016 enhanced bacterial multiplication in S H 1-lacking plants. Our findings suggest that HvEC-016 may be recognized by the plant immune system in a S H 1-dependent manner. Thus, our experimental approach is an effective tool for the characterization of effector/avirulence proteins of this important pathogen.