Análise da expressão gênica em bananeira cultivada com silício e inoculada com Fusarium oxysporum f. sp. cubense

Abstract

The banana crop is economically and socially important to Brazil. The low national productivity levels are attributed to factors such as high incidence of pests and diseases and the low level of technology employed in most producing areas. Panama disease, caused by the fungus Fusarium oxysporum f. sp. cubense (Foc) is endemic to all banana producing areas of the world. The control with fungicides is not feasible and the use of resistant cultivars is dependent on the appearance of new races of the pathogen. Control methods to the diseased are being searched and the use of silicon (Si) as an inducer of resistance is among the options because of its activity in multiple crops. The aims of this research were: a) to revise the scientific knowledge on the banana crop, on the Panama disease and the role of silicon in the activation of defense mechanisms; b) to analyze the expression of the genes encoding catalase, Phenylalanin Ammonia Lyase (PAL) and Pr3 (endochitinase) in two banana cultivars, Maçã and Grande Naine cultivated with silicon and inoculated with Foc. Real Time PCR was used with the SYBR Green methodology. The negative control had high levels of expression in both Maçã and Grande Naine cultivars for all the studied genes. The simultaneous use of silicon and inoculation with Foc influenced the expression of catalase in the cultivar Maçã in the first hours after inoculation. In this treatment, the pal and pr3 gens had their expression inhibited. The Si treatment showed a significant effect on the expression of pal in cultivar Maçã. Treatments without Si supplementation and inoculated with Foc presented levels of expression compared to the negative control for catalase and pal in both cultivars. These data will be important in shedding light into the complex metabolic pathways leading to defense responses in banana under the influence of Si.