Associação de Rhizoctonia solani Grupo de Anastomose 4 (AG-4 HGI e HGIII) à espécies de plantas invasoras de área de cultivo de batata
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Data
2010-06-01
Autores
Silva-Barreto, Fátima Aparecida da [UNESP]
Pereira, Wagner Vicente [UNESP]
Ciampi, Maisa Boff [UNESP]
Câmara, Marcos Paz Saraiva
Ceresini, Paulo Cezar [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Grupo Paulista de Fitopatologia
Resumo
Os grupos 3 e 4 de anastomose (AG-3 e AG-4) do fungo Rhizoctonia solani são importantes grupos associados à batata no mundo. No Brasil, o AG-3 é relatado afetando principalmente batata e fumo. Já o AG-4 causa perdas consideráveis em culturas de importância econômica, como a soja, o feijão e o amendoim, podendo ocorrer também em hortaliças como o espinafre, o pimentão, o brócolis, o tomate, a batata e frutíferas como o melão. Recentemente foi constatada, em Brasília-DF, a associação de R. solani a plantas invasoras em áreas de cultivo de batata. Entretanto, não há informação a respeito da etiologia do patógeno bem como do papel de espécies invasoras como outras hospedeiras no ciclo do patógeno. Objetivou-se com esse estudo caracterizar isolados de R. solani obtidos de batata e de outras três espécies de plantas invasoras associadas a áreas de cultivo da cultura: juá-de-capote [Nicandra physaloides (L.) Pers., Solanaceae], beldroega (Portulaca oleracea L., Portulacaceae), e caruru (Amaranthus deflexus L., Amaranthaceae). Foi confirmada a hipótese de que os isolados obtidos de R. solani de beldroega, caruru e juá-de-capote pertencem ao grupo 4 de anastomose e são patogênicos à batata, exceto o isolado de beldroega. Estes isolados apresentaram patogenicidade cruzada às três espécies e também patogênicos à maria-pretinha (Solanum americanum Mill.), uma outra espécie de Solanaceae invasora. A classificação dos isolados no grupo AG-4 HGI ou no grupo AG-4 HGIII (isolado de caruru) foi confirmada através de características culturais e moleculares (seqüenciamento da região ITS-5.8S do rDNA). Os resultados deste trabalho trazem implicações importantes para o manejo das podridões radiculares de Rhizoctonia em batata.
The anastomosis groups 3 and 4 (AG-3 and AG-4) of the fungus Rhizoctonia solani are important groups associated with potatoes worldwide. In Brazil, the AG-3 is reported affecting mainly potatoes and tobacco. The AG-4 cause considerable losses in crops of economic importance, such as soybean, beans and peanuts and may also occur in vegetables such as spinach, pepper, broccoli, tomatoes, potatoes and fruit such as melons. The association of R. solani with invasive plants was recently established in potato production areas from Brasília, DF. However, there is no information about the etiology of the pathogen as well as the role of invasive species as alternative hosts in the life cycle of the pathogen. The objective of this study was to characterize isolates of R. solani obtained from potatoes and three other invasive plant species associated with areas of potato production: Shoo-fly plant [Nicandra physaloides (L.) Pers., Solanaceae], pigweed (Portulaca oleracea L., Portulacaceae), and low-amaranth (Amaranthus deflexus L., Amaranthaceae). It was confirmed the hypothesis that the R. solani isolates obtained from pigweed, low-amaranth and Shoo-fly plant belong to the anastomosis group 4 and, except for the isolate from pigweed, are pathogenic to potatoes. These isolates were cross pathogencic to all the three weed species tested and also to American nightshade (Solanum americanum Mill.), another Solanaceae invasive of potato fields. The placement of the isolates in the group AG-4 HGI or in the group AG-4 HGIII (isolate from caruru) was confirmed by cultural and molecular characteristics (sequencing of the ITS-5.8S region of rDNA). The results of this study provide important implications for the management of the Rhizoctonia root rot in potatoes.
The anastomosis groups 3 and 4 (AG-3 and AG-4) of the fungus Rhizoctonia solani are important groups associated with potatoes worldwide. In Brazil, the AG-3 is reported affecting mainly potatoes and tobacco. The AG-4 cause considerable losses in crops of economic importance, such as soybean, beans and peanuts and may also occur in vegetables such as spinach, pepper, broccoli, tomatoes, potatoes and fruit such as melons. The association of R. solani with invasive plants was recently established in potato production areas from Brasília, DF. However, there is no information about the etiology of the pathogen as well as the role of invasive species as alternative hosts in the life cycle of the pathogen. The objective of this study was to characterize isolates of R. solani obtained from potatoes and three other invasive plant species associated with areas of potato production: Shoo-fly plant [Nicandra physaloides (L.) Pers., Solanaceae], pigweed (Portulaca oleracea L., Portulacaceae), and low-amaranth (Amaranthus deflexus L., Amaranthaceae). It was confirmed the hypothesis that the R. solani isolates obtained from pigweed, low-amaranth and Shoo-fly plant belong to the anastomosis group 4 and, except for the isolate from pigweed, are pathogenic to potatoes. These isolates were cross pathogencic to all the three weed species tested and also to American nightshade (Solanum americanum Mill.), another Solanaceae invasive of potato fields. The placement of the isolates in the group AG-4 HGI or in the group AG-4 HGIII (isolate from caruru) was confirmed by cultural and molecular characteristics (sequencing of the ITS-5.8S region of rDNA). The results of this study provide important implications for the management of the Rhizoctonia root rot in potatoes.
Descrição
Palavras-chave
beldroega, caruru, juá-de-capote, maria-pretinha, patogenicidade cruzada, pigweed, low-amaranth, Shoo-fly plant, American nightshade, cross pathogenicity
Como citar
Summa Phytopathologica. Grupo Paulista de Fitopatologia, v. 36, n. 2, p. 145-154, 2010.