Lignification and early abortive fungal colonies as indicators of partial resistance to rust in pea

Abstract

Ten recombinant inbred lines (RILs) of pea were selected, on the basis of rust (Uromyces fabae) reaction under screenhouse conditions and molecular makers associated with rust resistance, to study the association of lignification and early abortive fungal colonies in response to attack of U. fabae. The present investigation indicated that partial resistance to rust in pea, as measured by the area under disease progress curve (AUDPC), is negatively influenced by lignification (r = −0.48). Histological studies indicated a higher number of early abortive fungal colonies and delayed development of colonies in resistant RILs than susceptible ones. Furthermore, investigations into the association of phenylalanine ammonia lyase activity and total phenolics during the partial resistance reaction to U. fabae in pea revealed a very low correlation with AUDPC in the RILs. This study infers that lignification plays a major role and is the best indicator of partial resistance towards U. fabae in pea, by influencing colony size and the number of early abortive colonies. © 2016, Sociedade Brasileira de Fitopatologia.