Involvement of polyamines in resistance of wheat to Puccinia recondita

Abstract

Abstract 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 difluoromethylornithine (DFMO), an inhibitor of the polyamine biosynthesis enzyme ornithine decarboxylase. Increased putrescine and spermidine levels, especially conjugate and bound fractions were observed in leaves of both susceptible (Thatcher) and moderately resistant (Tc + Lr 21) near-isogenic lines following infection with P. recondita ; no significant changes in spermine levels were recorded. By contrast, highly resistant (Tc + Lr 32) leaves did not exhibit any significant alterations in polyamine titres. These observations suggest that DFMO can prevent leaf rust lesion development, and polyamines (putrescine and spermidine), especially their conjugates could play a role in the host-pathogen interactions.