INVOLVEMENT OF POLYAMINES IN RESISTANCE OF WHEAT TO PUCCINIA-RECONDITA

Complete protection of wheat seedlings (Triticum aestivum L., cv. Agra local) against infection by leaf rust fungus Puccinia recondita race 77' has been observed following foliar spray with 0.5 mM difluoromethy lornithine (DFMO), an inhibitor of the polyamine biosynthesis enzyme o rnithine decarboxylase. Increased putrescine and spermidine levels, es pecially conjugate and bound fractions were observed in leaves of both susceptible (Thatcher) and moderately resistant (Tc + Lr 21) near-iso genic lines following infection with P. recondita; no significant chan ges in spermine levels were recorded. By contrast, highly resistant (T c + Lr 32) leaves did not exhibit any significant alterations in polya mine titres. These observations suggest that DFMO can prevent leaf rus t lesion development, and polyamines (putrescine and spermidine), espe cially their conjugates could play a role in the host-pathogen interac tions. Copyright (C) 1996 Elsevier Science Ltd