Cuticle Layer as a Determining Factor for the Formation of Mature Appressoria of Erysiphe graminis on Wheat and Barley

Two sides of a leaf blade: Blumeria graminis needs chemical cues in cuticular waxes of Lolium perenne for germination and differentiation

“…This is reXected by decreased contact angles after the adhesive treatment. Altered physical leaf surface structures determined by sizes and shapes of epicuticular wax crystals were suggested to be important for the initiation and execution of B. graminis pre-penetration processes (Ellingboe 1972;Yang and Ellingboe 1972;Rubiales et al 2001). However, studies on barley and other cereals Zabka et al 2008) showed that stripping away epicuticular wax crystals did not aVect fungal pre-penetration properties, particularly epi-and intracuticular waxes of barley were demonstrated to share the same chemical composition .…”

Extracellular Materials of Fungal Structures: Their Significance at Prepenetration Stages of Infection

“…Similarly, germlings of P. coronata were bound to the leaf apparently by a combination offungal secretions and dissolved host wax [74] similar to the situation for Z.jamaicensis [47][48][49]. Yang and Ellingboe [75] suggested that appressorium formation by E. graminis on cereals was stimulated by the physical structure of epicuticular wax crystals. However, it is possible that if wax crystals and other cuticle components cannot be dissolved, close contact of the appressorium with the surface is impossible and penetration is prevented, a view supported by Nicholson [50].…”

Mechanisms by Which Genetically Controlled Resistance and Virulence Influence Host Colonization by Fungal and Bacterial Parasites

“…Firstly, some resistance mechanisms appear to operate at a number of stages of parasite development both before and after host penetration (Masri & Ellingboe, 1966;Ellingboe, 1972;Heath, 1974). At first sight this categorization has its merits, but it will not be adopted here for three reasons.…”

“…The best evidence comes from the study of appressorium formation by Erysiphe graminis on eceriform mutants of barley (Yang & Ellingboe, 1972).…”

“…The speed with which HR occurs, the colouration of necrotic cells, the extent of necrosis in invaded and non-invaded cells and the extent of parasite development beyond the necrotic area all vary (Heath, 1974;Littlefield & Aronson, 1969;Littlefield, 1973;Skipp & Deverall, 1972;Coffey & Allen, 1983;Coffey, 1976;Ellingboe, 1972;Maclean & Tommerup, 1979). The speed with which HR occurs, the colouration of necrotic cells, the extent of necrosis in invaded and non-invaded cells and the extent of parasite development beyond the necrotic area all vary (Heath, 1974;Littlefield & Aronson, 1969;Littlefield, 1973;Skipp & Deverall, 1972;Coffey & Allen, 1983;Coffey, 1976;Ellingboe, 1972;Maclean & Tommerup, 1979).…”