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Physiology and Biochemistry

Inhibition of Cronartium fusiforme by Loblolly Pine Callus. W. R. Jacobi, Graduate research assistant, Department of Plant Pathology, North Carolina State University, Raleigh 27650, Current address: Department of Botany and Plant Pathology, Colorado State University, Fort Collins 80523; Phytopathology 72:143-146. Accepted for publication 1 April 1981. Copyright 1982 The American Phytopathological Society. DOI: 10.1094/Phyto-72-143.

Loblolly pine callus grown in vitro inhibited mycelial growth of Cronartium fusiforme derived from both basidiospores and urediospores. Phosphate buffer washes of loblolly and slash pine callus inhibited growth of C. fusiforme in culture. Colonization of susceptible loblolly seedlings by C. fusiforme was restricted by growing seedlings in the callus washes, or on existing callus, and by inducing callus formation in the seedlings. The inhibitory factor from pine callus was heat labile, of high molecular weight, and water soluble.