Data/hora: 24/09/2024 00:06:08

Biblioteca(s): 	Embrapa Soja.	
Data corrente: 	06/04/2004	
Data da última atualização: 	27/07/2007	
Autoria: 	ALMEIDA, A. M. R.; MARIN, S. R. R.; BINNECK, E.; PIUGA, F. F.; SARTORI, F.; COSTAMILAN, L. M.; TEIXEIRA, M. R. O.; LOPES.	
Título: 	Pathogenicity, molecular analysis, and cercosporin content of brazilian isolates of Cercospora kikuchii.	
Ano de publicação: 	2004	
Fonte/Imprenta: 	In: WORLD SOYBEAN RESEARCH CONFERENCE, 7.; INTERNATIONAL SOYBEAN PROCESSING AND UTILIZATION CONFERENCE, 4.; CONGRESSO BRASILEIRO DE SOJA, 3., 2004, Foz do Iguassu. Abstracts of contributed papers and posters. Londrina: Embrapa Soybean, 2004.	
Páginas: 	p. 69-70.	
Série: 	(Embrapa Soja. Documentos, 228).	
Idioma: 	Inglês	
Notas: 	Editado por Flávio Moscardi, Clara Beatriz Hoffmann-Campo, Odilon Ferreira Saraiva, Paulo Roberto Galerani, Francisco Carlos Krzyzanowski, Mercedes Concordia Carrão-Panizzi.	
Conteúdo: 	The fungus Cercospora kikuchii is involved in defoliation of soybean plants, and is normally associated with Septoria glycines in late season. No genetic resistance has been described. The screening of resistant genotypes requires previous knowledge of the fungus. This work was undertaken to evaluate pathogenic and genetic diversity among isolates of Cercospora kikuchii from different areas of Brazil. Seventy-two isolates obtained from purple stained seeds showed differences in phenotypic variation. Comments from the literature associated other Cercospora spp. with purple stain, indistinguishable from those produced by C. kikuchii. Moreover, cercosporin content and rate of colony development was higly variable among isolates. A strong correlation was found between cercosporin content and virulence. Genetic differentiation among and within populations was observed based on 86 RAPD loci. RAPD analysis permitted clustering all isolates into 6 groups. No relationship was identified between isolates and geographic origin or cercosporin content. The sequences of the intergenic spacer region (ITS1-5.8S-ITS2) from 14 isolates chosen according to the previous clustering analysis, were determined by the dideoxy chain-termination method and the chromatograms basecalled by PHRED. High quality sequence fragments (PHRED score >20) showed high similarities to the GenBank accession no. AF291708 sequence, proving that all isolates used belong to the species C. kikuchii. It is clear from this work that populations of C. kikuchii are pathogenically, genotypically and geographically variable. Moreover, C. kikuchii has great phenotypic variation and cercosporin could be a good parameter for choosing a good isolate for screening resistant or tolerant cultivars. Considering that this pathogen is easily transmitted by seeds it is not surprise to find the same haplotypes in different regions. Migration could be favoured by infected seeds as demonstrated by the clustering analysis.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Soja (CNPSO)	
Exemplares: 	CNPSO - (23687-1) - UMT - PL - -- - RF 633.34072 - W927a -  - DIS