Microscopic observations of a compatible host/pathogen interaction between a potential biocontrol agent (Uromyces pencanus) and its target weed (Nassella neesiana)

Uromyces pencanus is a prospective biocontrol agent for Nassella neesiana in Australia and New Zealand. The infection process of U. pencanus urediniospores in leaves of its susceptible host N. neesiana was found to be similar to that of most other rust species. A pattern against which to compare nonhost reactions in host range experiments was achieved using a modification of Bruzzese and Hasan's whole leaf clearing and staining technique. The staining of microtome leaf sections provided supplemental information about this pathosystem.