Freqüência de biovares de ralstonia solanacearum em diferentes cultivares e épocas de cultivo de batata no rio grande do sul

Abstract

RESUMOA presença das biovares I e/ou II de Ralstonia solanacearum em uma lavoura de batatas (Solanum tuberosum) tem influência direta no sucesso das medidas adotadas para controlar a murcha bacteriana. As biovares diferem entre si em relação à agressividade, latência e sobrevivência. Assim, um experimento de campo foi conduzido em uma área naturalmente infestada em duas épocas de cultivo com os objetivos de verificar (1) a incidência de biovares I e/ou II, (2) a relação entre biovar e época de plantio e (3) a relação entre biovar e cultivar de batata. Os isolados obtidos de plantas das cultivares Achat, Baronesa, Elvira, Macaca, Monte Bonito e Trapeira foram identificados como biovar I ou II através da PCR, utilizando os oligonucleotídeos iniciadores T3A e T5A. Ambas as biovares foram encontradas na área naturalmente infestada. De 73 isolados de R. solanacearum, 94,5% foram identificados como biovar II e 5,5% como biovar I. A biovar II foi isolada dos cultivos de primavera e de outono, independente da cultivar, mas a I apenas do cultivo de primavera e de plantas assintomáticas das cultivares Achat e Macaca. A maior população da biovar I nestas duas cultivares pode ser uma evidência da possível relação entre biovar e cultivar.Palavras-chave adicionais: Murcha bacteriana, Solanum tuberosum, PCR ABSTRACT Frequency of biovars of Ralstonia solanacearum on different cultivars and potato planting seasons in Rio Grande do SulThe occurrence of biovars I and/or II of Ralstonia solanacearum in a potato (Solanum tuberosum) field has direct consequences for the success of the measures adopted to control bacterial wilt. Biovars differ regarding aggressiveness, latency and survival. An experiment was conducted in a naturally infested potato field in two seasons to find (1) the incidence of biovars I and II, (2) the relationship between biovar and planting season, and (3) the relationship between biovar and potato cultivar. Bacterial isolates from potato cultivars Achat, Baronesa, Elvira, Macaca, Monte Bonito, and Trapeira were identified as biovar I or II through PCR, using T3A and T5A primers. Both biovars I and II were found in the naturally infested field. Among 73 strains, 5.5 and 94.5 % were identified as biovar I and II, respectively. Biovar II was found in the spring and in the fall, regardless of the cultivar, but biovar I only in the spring season and on symptomless plants of Achat and Macaca cultivars. The highest population of biovar I on these two cultivars may be evidence for a possible relationship between biovar and cultivar. INTRODUÇÃOA ocorrência da bactéria Ralstonia solanacearum (Smith) Yabuuchi et al. , agente causal da murcha bacteriana (MB), é um dos fatores mais limitantes da cultura da batata (Solanum tuberosum L.) no Brasil. De acordo com recomendações para o manejo integrado da doença, o uso de cultivares resistentes, plantio de batata semente livre do patógeno e a rotação de culturas são algumas das medidas mais importantes a serem consideradas (Takatsu & Lopes, 1997). No entanto, o sucesso do manejo...

Occurrence and diversity of Ralstonia solanacearum populations in Brazil

“…Trials done in Rio Grande do Sul (RS), for instance, between 1997 and 1999, characterized 94% and 6% of R. solanacearum isolates as R3Bv2 and R1Bv1, respectively, in different potato cultivars and planting seasons (MACIEL et al, 2001;MORAES, 2002). High frequency of R3Bv2 was expected and confirms the hypothesis of prevalence of this biovar in that State, probably due to milder temperatures (14 to 22 o C) during the major growing season.…”

“…Subsequently, its occurrence was reported in potato in South of Brazil, although in lower frequency than R3Bv2 (LOPES; NAZARENO;FURIATTI, 1993;MACIEL et al, 2001;MORAES, 2002;SILVEIRA et al, 2005). Moreover, under special conditions of moisture and temperature, it has caused significant losses in commercial eucalypt nurseries in the States of Espírito Santo, Santa Catarina, Maranhão, Minas Gerais, Bahia, Pará, and Goiás (ALFENAS et al, 2006;AUER;.…”

“…It is most commonly found, with no exclusivity, in crops in the South and Southeast, where most of the potato is grown in country (FRENCH et al, 1993;NAZARENO;FURIATTI, 1993;MACIEL et al, 2001;MORAES, 2002). Besides affecting potato crops, this race was found associated to geranium (Pelargonium zonale) in the State of São Paulo (ALMEIDA et al, 2003).…”

Caracterização in vitro e in planta de uma proteína quimérica com atividade antimicrobiana à Ralstonia solanacearum

“…Biovars 4 and 5 have not been reported in the country (Table 1). Lopes et al, 1993;French et al, 1993;Maciel et al, 2001Maciel et al, , 2004Silveira et al, 2002Silveira et al, , 2005Santana et al, Coelho Netto et al, 2003Silveira et al, 2006;Costa et al, 2007;Lima Neto et al, 2009;Lima et al, Sudo et al, 1983;Dianese and Takatsu, 1985;Dristig et al, 1988;Robbs et al, 1988;Alfenas et al, 2006;Auer;Santos;Rodrigues Neto, 2008;Mafia et al, 2012;Marques et al, 2012;Fonseca et Martins et al, 1988;Mariano et al, 1988Mariano et al, , 1989Coelho Netto et al, 2004;Malavolta Júnior et al, 2008;Garcia et Race 1, including biovars 1 and 3, is frequently found in the Northern region, which reinforces indications that R. solanacearum has its center of origin in the Amazon . However, this race has affected many tomato, potato, bell pepper, gilo, and tobacco crops in all Brazilian regions (MARTINS et al, 1988;COELHO NETTO et al, 2003;DUARTE et al, 2003;MALAVOLTA JÚNIOR et al, 2008;LIMA NETO et al, 2009;LIMA et al, 2010).…”

“…R1Bv1 (Race 1, Biovar 1) was reported in solanaceae in the Midwestern region of Brazil by Takatsu et al in 1984. Subsequently, its occurrence was reported in potato in South, although in lower frequency than R3Bv2 (LOPES et al, 1993;MACIEL et al, 2001;SILVEIRA et al, 2002;. Moreover, under special conditions of moisture and temperature, it has caused significant losses in commercial eucalypt nurseries in the States of Espírito Santo, Santa Catarina, Maranhão, Minas Gerais, Bahia, Pará, and Goiás (ALFENAS et al, 2006;AUER;SANTOS;RODRIGUES NETO, 2008).…”