The anthracnose, caused by the fungus Colletotrichum lindemuthianum, is one of the most destructive diseases affecting bean crop. With the objective to find alternative to the control this disease, this study investigated, at the microscopic level, the effect of silicon (Si) on bean resistance to infection by C. lindemuthianum. Bean plants (cv. 'Pérola') were grown in nutrient solution containing 0 (-Si) or 2 mM (+ Si) of Si and inoculated in the V4 growth stage with a suspension of conidia of C. lindemuthianum. The disease severity decreased by 52% in the leaves of plants supplied with Si (4.4%) in relation to the leaves of non supplied plants (8.5%). Observations of bean leaves of plants not supplied with Si by scanning electron microscopy revealed morphological changes in the veins in contrast with the leaves of plants supplied with Si. By using the X-ray microanalysis, it was found higher concentrations of the minerals sulfur, potassium and Si in the leaves of plants supplied with Si. In conclusion, the supply of Si in bean plants was important to reduce the symptoms of anthracnose.
Colletotrichum lindemuthianum; Phaseolus vulgaris L.; scanning electron microscopy; X-ray microanalysis; mineral nutrition
