Cytologicai responses in the hypersensitive reaction in cotyledon and stem tissues of Brassica napus after infection by Leptosphaeria maculans

摘要

A hypersensitive response (HR) occurs after infection of cotyledon, leaf and stem of Brassica napus cv. Surpass 400 by an avirulent strain of Leptosphaeria maculans. The cotyledon or the sixth true-leaf stages of plants were inoculated with pycnidiospores of L. maculans (strain UWA Pll). For the first time in this specific pathosystem and its HR, we report condensation of cytoplasm, shrinkage in cell size and nuclear DNA fragmentation in cotyledon tissues, and in stem tissues, shrinkage and condensation of the cytoplasm, chromatin fragmentation and lobing of the nucleus.