The Moniliophthora perniciosa - Cacao pod pathosystem: Structural and activated defense strategies against disease establishment

The infection process of Moniliophthora perniciosa on cacao pods of different resistance sources to witches' broom disease of cacao; i.e., TSH1188 (resistant) and Catongo (susceptible), was evaluated at the histological and enzymatic levels. Cacao pods were inoculated with a basidiospore suspension and were assessed weekly for witches' broom symptoms. Histological evaluations revealed differences between genotypes in the pre and post penetration events of M. perniciosa. Compared with catongo, the onset and development of fungal colonization were delayed and less intense in pods of TSH1188. Also, peroxidase activities were higher during the early stages of the infection (0-48 HAI) in the incompatible interaction. These results suggested that TSH1188 cacao pods have structural and biochemical mechanisms which may hinder/delay the infection of M. perniciosa.