The Ultrastructure of the Host-parasite Interface in the Needles of Pinus nigra Infected with Lophodermella sulcigena

Abstract

The hyphae of Lophodermella sulcigena are usually surrounded by an electron-opaque matrix when growing in the needles of Corsican pine (Pinus nigra var. maritima). The host-parasite interface is of a type which has been little studied; the intercellular hyphae kill the mesophyll cells of the host ahead of themselves and their walls are separated from those of the host by a matrix. The first signs of injury to the host are disorganized membrane systems, particularly the thylakoid and bounding membranes of the chloroplasts break down. The dead host cells are filled with resin or tannin in which only the starch grains are visible.