Sobrevivência de Xanthomonas campestris pv. viticola em tecido infectado de videira

Abstract

RESUMO -Tecidos de plantas infectados constituem uma importante fonte de inóculo primário para fitobacterioses. O objetivo deste trabalho foi investigar a sobrevivência de Xanthomonas campestris pv. viticola (Xcv), agente do cancro bacteriano da videira, em tecidos infectados na superfície do solo e durante a compostagem de restos de poda. Mudas de videira 'Festival' foram inoculadas com mutante resistente à rifampicina Xcv2Rif e mantidas em casa de vegetação até apresentarem alta severidade da doença. No primeiro experimento, ramos fragmentados e folhas inteiras destas plantas foram acondicionados em bolsas de malha plástica e colocados na superfície de microparcelas. No segundo experimento, ramos e folhas fragmentados foram acondicionados em bolsas plásticas e depositados no interior de pilhas de compostagem de restos de poda de videira. A sobrevivência de Xcv2Rif em tecidos infectados foi monitorada a intervalos de 8 e 10 dias a partir do início do primeiro e segundo experimentos, respectivamente. No primeiro experimento, foi também avaliada a decomposição de tecidos, e no segundo, as curvas de temperatura das pilhas, conteúdo de fenóis e microbiota antagonista a Xcv2 Rif. O patógeno sobreviveu em altas populações até 80 dias em tecidos infectados na superfície do solo. A compostagem eliminou Xcv2Rif de restos culturais em 10 dias, devido às altas temperaturas, liberação de compostos fenólicos e antagonismo microbiano. Concluindo, em tecidos infectados de videira Xcv sobrevive na superfície do solo por, pelo menos, 80 dias mas é eliminada pela compostagem em 10 dias. Termos para Indexação: Cancro bacteriano da videira, restos de cultura, epidemiologia, Xanthomonas campestris pv. viticola, erradicação. SURVIVAL OF Xanthomonas campestris pv. viticola IN INFECTED TISSUES OF GRAPEVINEABSTRACT -Infected plant tissues are an important primary inoculum sources for plant bacterial diseases. This study investigated the survival of Xanthomonas campestris pv. viticola (Xcv), the agent of bacterial canker of grapevine in infected tissues on soil surface and during composting process of pruning residues. Grapevine plants cv. Festival were inoculated with a mutant resistant to rifampicin Xcv2 Rif and maintained under greenhouse conditions until presenting high disease severity. In the first experiment, fragmented shoots and entire leaves from these plants, were placed into mesh bags and located on the surface of microplots. In the second experiment fragmented shoots and leaves were also placed into mesh bags and located inside composting piles of grapevine pruning residues. The survival of Xcv2Rif in infected tissue was monitored at 8 and 10 days intervals from 1 and 2 experiment setting, respectively. In the experiment 1 tissue decomposition was also evaluated and in the experiment 2, pile temperature curves, phenolyc content, and antagonism against Xcv2Rif were analyzed. The pathogen survived in high populations for at least 80 days in grapevine-infected tissues on soil surface. The composting process eliminated Xcv2Rif ...

Altitude and management affect soil fertility, leaf nutrient status and Xanthomonas wilt prevalence in enset gardens

“…Considering standards in banana crops, our results were comparable for N, Mn and Fe, above optimum for P and K, and deficient for Ca, Mg and micronutrients such as Cu and Zn. Our results suggest a potential additional drawback of over-fertilization, as low Ca and Mg could be linked to a reduced absorption caused by high K levels (Baker and Pilbeam, 2007;Hiltunen and White, 2002;Lahav and Turner, 1989), and deficiency in micronutrients may be induced by excessive rates of P (Huang et al, 2000;Singh et al, 1988;Soltangheisi et al, 2013). A comparison to reported enset leaf nutrients in the literature confirms the high K and low Ca levels in our study area (Table 7).…”

“…From our observations, two potential mechanisms on how nutrient levels may influence Xanthomonas susceptibility are in line with the data. First, excessive rates of P may interfere with micronutrient uptake (Huang et al, 2000;Singh et al, 1988;Soltangheisi et al, 2013), and micronutrient deficiencies have been shown to increase susceptibility to Fusarium wilt in banana crops (Hecht-Buchholz et al, 1998). In our study area, a significantly higher P av was observed in the soils of symptomatic farms, while an imbalance in micronutrients is likely based on the leaf analysis reported (Tables 3 and 7; Fig.…”

Risk assessment of Xanthomonas citri pv. viticola for the EU

“…Disease progression can be slowed down to some extent by implementing strong sanitation pruning, thereby reducing yields but avoiding the death of plants. Nonetheless, the pathogen was reported to survive for at least 80 days in grapevine‐infected tissues on the soil surface (Silva et al., 2012 ).…”

Efeito do tratamento de bacelos de videira 'Red Globe' no controle do cancro bacteriano causado por Xanthomonas campestris pv. viticola

“…O patógeno sobrevive em videira e outras hospedeiras infectadas, com ou sem sintomas (NASCIMENTO; MARIANO, 2004;PEIXOTO et al, 2007) e em restos culturais (SILVA et al, 2012). Destas fontes de inóculo, Xcv é disseminada durante os tratos culturais por respingos de água de chuva e irrigação, pulverizações, ferramentas de cultivo não desinfestadas, roupas e veículos (NASCIMENTO; MARIANO, 2004).…”