Ultrastructural studies on the development of uromyces phaseoli in bean phaseolus vulgaris cultivar favorit leaves protected by elicitors of phyto alexin accumulation
Ebrahim Nesbat, F.; Hoppe, H.H.; Heitefuss, R.
Phytopathologische Zeitschrift 103(3): 261-271
ISSN/ISBN: 0031-9481 Accession: 006860237
Glucans, which elicit phytoalexin accumulation, were infiltrated into primary leaves of a susceptible bean variety. When leaves were inoculated with uredospores of U. phaseoli, 5 days after elicitor treatment rust development was completely inhibited. Elicitor treatment had no effect on spore germination and appressoria formation of leaf surfaces. Two days after inoculation in treated leaves many substomatal vesicles were destroyed or heavily damaged. Some apparently morphologically normal vesicles were also detected. They allowed scattered intercellular growth of the rust fungus; however, no haustoria could be found in the treated tissue. The absence of haustoria was apparently related to the deposition of electron-opaque material between the plasmalemma and cell wall of plant cells at the sites of contact between host and fungal cells. These deposits were found in the treated tissue 2 days after inoculation in response to contact with disorganized substomatal vesicles and cells of intercellular hyphae. Host cells containing deposits showed sometimes disorganized membranes and cytoplasm. In elicitor treated, non-inoculated tissue and in water-treated, inoculated control tissue no comparable deposition of electron-opaque material was observed.