RESUMO
Continuous use of glyphosate in citrus groves in the Gulf of Mexico region has selected for resistant Parthenium hysterophorus L. populations. In this study, the target-site and non-target-site resistance mechanisms were characterized in three putative glyphosate-resistant (GR) P. hysterophorus populations, collected in citrus groves from Acateno, Puebla (GR1 and GR2) and Martínez de la Torre, Veracruz (GR3), and compared with a susceptible population (GS). Based on plant mortality, the GR populations were 9.2-17.3 times more resistant to glyphosate than the GS population. The low shikimate accumulation in the GR population confirmed this resistance. Based on plant mortality and shikimate accumulation, the GR3 population showed intermediate resistance to glyphosate. The GR populations absorbed 15-28% less 14C-glyphosate than the GS population (78.7% absorbed from the applied) and retained 48.7-70.7% of 14C-glyphosate in the treated leaf, while the GS population translocated ~68% of absorbed herbicide to shoots and roots. The GR3 population showed the lowest translocation and absorption rates, but was found to be susceptible at the target site level. The 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene sequence of the GR1 and GR2 populations showed the Pro106-Ser mutation, conferring 19- and 25-times more resistance in comparison to the GS population, respectively. Reduced absorption and impaired translocation conferred glyphosate resistance on the GR3 population, and contributed partially to the resistance of the GR1 and GR2 populations. Additionally, the Pro-106-Ser mutation increased the glyphosate resistance of the last two P. hysterophorus populations.
Assuntos
Glicina/análogos & derivados , Herbicidas/farmacologia , Tanacetum parthenium/efeitos dos fármacos , Tanacetum parthenium/metabolismo , 3-Fosfoshikimato 1-Carboxiviniltransferase , Glicina/farmacologia , Resistência a Herbicidas , Mutação/genética , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Brotos de Planta/efeitos dos fármacos , Brotos de Planta/metabolismo , GlifosatoRESUMO
In a new approach to microbial gallic acid production by Aspergillus fischeri MTCC 150, 40gL-1 oftannic acid was added in two installments during the bioconversion phase of the process (25gL-1 and 15gL-1 at 32 and 44h respectively). The optimum parameters for the bioconversion phase were found to be temperature: 35ºC, pH: slightly acidic (3.3-3.5), aeration: nil and agitation: 250 rpm. A maximum of 71.4 percent conversion was obtained after 71h fermentation with 83.3 percent product recovery. The yield was 7.35 g of gallic acid per g of biomass accumulated and the fermenter productivity was 0.56 g of gallic acid produced per liter of medium per hour.
Em uma nova abordagem para produção de ácido gálico por Aspergillus fischeri MTCC 150, adiciona-se 40 g.L-1 de ácido tânico em dois momentos da fase de bioconversão do processo (25 g.L-1 e 15 g.L-1 a 32h e 44h, respectivamente). Os parâmetros ótimos para a fase de bioconversão foram: temperatura 35ºC, pH levemente ácido (3,3 a 3,5), nenhuma aeração e agitação 250 rpm. Um máximo de 71,4 por cento de conversão foi obtido após 71h de fermentação, com 83,3 por cento de recuperação do produto. O rendimento foi 7,35g de ácido gálico por g de biomassa acumulada e a produtividade do fermentador foi 0,56g de ácido gálico por litro de meio por hora.