Data/hora: 24/09/2024 21:44:13

Biblioteca(s): 	Embrapa Soja.	
Data corrente: 	30/11/2005	
Data da última atualização: 	02/12/2005	
Autoria: 	ALMEIDA, A. M. R.	
Título: 	Stem necrosis in soybean plants: a historical view.	
Ano de publicação: 	2005	
Fonte/Imprenta: 	Virus Reviews & Research, Rio de Janeiro, v. 10, p. 30, Nov. 2005. Supplement.	
Idioma: 	Inglês	
Notas: 	Edição dos Resumos da XVI National Meeting of Virology, nov. 2005.	
Conteúdo: 	Stem necrosis is a plant symptom that was observed in soybeans in several counties of Southwestern Goiás State, in the 2001 growing season. Initially, the disease etiology, which caused total yield loss in several soybean fields, was associated to fungi. In the following years similar symptoms were reported in Bahia, Maranhão, Mato Grosso and Paraná States. Yield loss assessments in those States estimated total losses in 3,000 ha and partial losses (<70%) in in 5,000 ha. Severe mosaic and bacterial bud blight were founds associated to stem necrosis. Initial etiology studies on the pathogen involved mechanical inoculation, electron microscopy (EM), transmission by aphids (Myzus persicae), whiteflies (Bemicia tabaci), soybean seeds and RT-PCR. The results indicated that a carlavirus was associated to the symptoms. EM exams of the infected tissues showed the presence of long particles. The virus was propagated by whiteflies but not by aphids and was also not transmitted by seeds. Amplification of the viral RNA, using primers specific to carlavirus produced a fragment of - 120 pb with 88.4% homology with the Cowpea mild mottle virus. Yield loss assessments in regions where the virus was identified confirmed that it can severely affect the crop in Brazil. Although the virus has a narrow range of hosts, two species can be source of inoculum in Brazil: Arachys repens e Desmodium tortuosum. Preliminary studies confirmed that the genetic resistance is controlled by polygenes and that few genotypes are tolerant to the infection.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Soja (CNPSO)	
Exemplares: 	CNPSO - (25802-1) - UPC - SP - -- - 10500 -  - 10500 - DIS