Ocorrência e caracterização do complexo de espécies causadoras da mancha bacteriana do tomateiro no Alto Vale do Rio do Peixe, SC

Abstract

RESUMOO objetivo deste trabalho foi identificar isolados de Xanthomonas causadores da mancha bacteriana do tomateiro para consumo in natura, provenientes da região do Alto Vale do Rio do Peixe, SC, Brasil, bem como caracterizá-los quanto à sensibilidade in vitro ao cobre. As espécies foram determinadas por similaridades de perfis genômicos gerados por BOX-PCR e a sensibilidade ao cobre foi estabelecida utilizando-se o meio CYE suplementado com sulfato de cobre nas concentrações de 50, 100 e 200 μg/mL. Do total de 44 isolados, 80% foram identificados como X. gardneri, 11% como X. perforans e 9% como X. vesicatoria. De acordo com a reação ao cobre, os isolados foram agrupados em quatro classes (S, sensíveis; MS, moderadamente sensíveis; MI, moderadamente insensíveis; I, insensíveis). Quanto à sensibilidade ao cobre, 98% de todos os isolados foram sensíveis a 200 μg/mL, sugerindo que aparentemente, a dosagem recomendada de produtos à base de cobre em campo, 10 vezes maior que a dosagem limítrofe utilizada nos testes in vitro, ainda é eficiente para as diferentes espécies da bactéria. Palavras-chave: Xanthomonas euvesicatoria, X. gardneri, X. perforans, X. vesicatoria, BOX-PCR, cobre, controle químico. ABSTRACT Occurrence and characterization of the species complex causing tomato bacterial spot in "Alto Vale do Rio do Peixe", SC, BrazilThe aim of this study was to identify at the species level Xanthomonas strains causing tomato bacterial spot in the region of "Alto Vale do Rio do Peixe", state of Santa Catarina, Brazil, as well as to determine their in vitro sensitivity to copper. Species were determined by similarity analysis of genomic profiles generated by BOX-PCR and sensitivity to copper was established using the CYE medium supplemented with copper sulfate at concentrations of 50, 100 and 200 μg/mL. Of the 44 isolates, 80% were identified as X. gardneri, 11% as X. perforans and 9% as X. vesicatoria. According to the response to copper, the isolates were divided into four classes (S, sensitive; MS, moderately sensitive; MI, moderately insensitive; I, insensitive). Regarding the sensitivity to copper, 98% of all isolates were sensitive at 200 μg/mL, suggesting that the recommended dosage of copper-based products registered for the crop may still provide effective control of the different bacterial species.

Widespread distribution of Xanthomonas perforans and limited presence of X. gardneri in Brazil

“…gardneri might be evidence of a horizontal gene transfer between these two species. In fact, despite differing in optimum temperature for disease development (Araújo et al ., ), these two species can coexist in the same field (Costa et al ., ). Seed introduction and volunteer plants as inoculum sources are possible explanations for the simultaneous presence of X .…”

“…BOX‐PCR markers are more robust for identification of strains belonging to the genus Xanthomonas than REP and ERIC markers (Rademaker et al ., ), and have been efficient for characterization and identification of the causal agents of the tomato bacterial spot complex (Bouzar et al ., ; Costa et al ., ). In addition, X .…”

Xanthomonas perforans and X. gardneri associated with bacterial leaf spot on weeds in Brazilian tomato fields

“…PCR with specific primers (Koenraadt et al 2009) was made following the protocol adjusted by Pereira et al (2011). BOX-PCR (Versalovic et al 1991) was then carried out according to the protocol established by Costa et al (2012). A dendrogram was generated by GelCompar II version 6.5 program (Applied Maths) using Dice coefficient and UPGMA method.…”

Residual polysaccharides from fungi reduce the bacterial spot in tomato plants

“…The strains were characterized using pulsed-field gel electrophoresis (PFGE). In the tomato-producing region of Alto Vale do Rio do Peixe, Santa Catarina state, Brazil, the BOX-PCR technique was employed to analyze the causative agents of the bacterial spot, and almost 80% of the isolates associated were identified as Xanthomonas gardneri, 11% as Xanthomonas perforans and 9% as Xanthomonas vesicatoria (Costa et al 2012).…”