Contributions to the study of infection of Pinus pinaster Ait. by the pathogenic fungi Botrytis cinerea

Abstract

Maritime pine (Pinus pinaster Ait.) is one of the three main European pine species and the most important conifer in the Portuguese territory, assuming a preponderant ecological role and vital economical importance. However, the declining P. pinaster population in Portugal is constantly afflicted by the pathogenic agent Botrytis cinerea, a necrotrophic fungi infecting mostly seedlings and causing deficient self-regeneration of pine forests, coupled with the devastation of pine nurseries. We developed an array of tools for P. pinaster research, which have been recently put to use in understanding the underlying mechanisms of infection by B. cinerea. These include optimization of gDNA and RNA extraction protocols, construction of a cDNA library from leaf tissue of P. pinaster and isolation of genes of interest (oxidative stress, primary and secondary metabolism, pathogenesis related genes), as well as the establishment of suspension cell cultures to function as a working model for infection. Thereon, research has focused mainly on four areas of host resistance to biotic stress, namely: a) hypersensitive response (HR) and the oxidative burst of reactive oxygen species (ROS) production; b) secondary metabolism response and cell wall lignification; c) primary metabolism of sugars and the glucose transport system in infected cells; d) transduction of the defence signal. Results indicate a concerted response of P. pinaster suspension cells to infection, which suggest the likely recognition of the pathogenic agent at a molecular level.