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DYNAMIC EXPERIMENTAL EVIDENCE FOR THE PLASMA MEMBRANE ATPase DOMAIN HYPOTHESIS OF HAUSTORIAL TRANSPORT AND FOR IONIC COUPLING OF THE HAUSTORIUM OF ERYSIPHE GRAMINIS TO THE HOST CELL (HORDEUM VULGARE)
Author(s) -
GAY JOHN L.,
SALZBERG A.,
WOODS A. M.
Publication year - 1987
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1987.tb02925.x
Subject(s) - haustorium , cytoplasm , fusicoccin , biology , coleoptile , hordeum vulgare , biophysics , fluorescein , atpase , botany , microbiology and biotechnology , fluorescence , host (biology) , biochemistry , poaceae , ecology , physics , enzyme , quantum mechanics
S ummary Barley coleoptile epidermes, prepared in special mounts for microscopic examination, were infected with Erysiphe graminis D.C. ex Merat (powdery mildew) and, after 2 d, used for experiments in which reagents were introduced to the exposed underside. Fluorescein, introduced by means of fluorescein diacetate, fluoresced for periods of over 45 min in the epidermal cytoplasm and for longer in the Haustoria which had developed. Cytoplasmic streaming in the epidermal cells continued for over 24 h. The duration of fluorescence was reduced by FCCP, but fusicoccin increased both the duration and intensity. In similar experiments in which the upper surfaces of infected leaves were detached so that the epidermal cells were disrupted and the extrahaustorial membranes were in direct contact with the experimental solutions, the duration of haustorial fluorescence was shorter than as described above in controls and with FCCP. Fusicoccin had no effect. The fluorescence, interpreted as an indicator of intracellular pH, confirms the ATPase domain hypothesis of haustorial transport and indicates that each haustorium is ionically coupled to the cytoplasm of its host cell.