VIEW ARTICLE

Physiology and Biochemistry

Hypersensitive Reactivity in Potato: Transition from Inactive to Active State Induced by Infection with an Incompatible Race of Phytophthora infestans. N. Furuichi, Plant Pathology Laboratory, Faculty of Agriculture, Nagoya, Japan; K. Tomiyama(2), and N. Doke(3). (2)(3) Plant Pathology Laboratory, Faculty of Agriculture, Nagoya, Japan. Phytopathology 69:734-736. Accepted for publication 6 February 1979. Copyright 1979 The American Phytopathological Society. DOI: 10.1094/Phyto-69-734.

We reported previously that surface cells of fresh potato tuber disks had low ability to react hypersensitively to infection with an incompatible race of Phytophthora infestans. These cells acquired hypersensitive reactivity gradually and attained almost full ability to react about 16–20 hr after cutting. We now report that when the surface tissue zone (0.2–0.3 mm thick) from aged disks was removed with a razor blade, cells of the freshly cut surface also had high ability to react. This indicates that the low ability of freshly cut disks to react is not caused by wounding but is due to the inherent low ability of intact cells. Treating the cut ends of petioles of unfolding young leaflets with 5 ppm blasticidin S and inoculating the intact epidermis with the incompatible race greatly reduced hypersensitive cell death. These results indicate that an intact potato cell, from tubers as well as from leaves, has very low initial ability to react hypersensitively to infection. The ability is induced by infection with an incompatible race of P. infestans or by wounding. We propose to name these two states “inactive” (state I) and “active” (state II). Transition from state I to state II requires protein synthesis.