Disease development and β-1,3-glucanase expression following leaf rust infection in resistant and susceptible near-isogenic wheat seedlings

Abstract To determine the association of pathogenesis-related (PR) proteins with resistance conferred by the genes Lr29 and Lr34 to leaf rust, three near-isogenic wheat lines [Palmiet (Pa), Pa/ Lr29 (Pa*4/RL6080[ Lr29 ]) and Pa/ Lr34 (Pa*4/RL6058 [ Lr34 ])] were infected with the fungus Puccinia recondita f. sp. tritici . Activity levels and an immunological profile of the PR protein, β-1,3-glucanase, were recorded in relation to fungal structure development. Compared with the susceptible control, Palmiet, infection and colonization of leaf tissue were inhibited in lines containing either Lr29 or Lr34 . Induction of β-1,3-glucanase activity was observed in all lines, including Palmiet, concurrent with the formation of substomatal vesicles and subsequent differentiation of the pathogen. Following leaf rust infection, four major β-1,3-glucanases were revealed with Western blot analysis. Higher levels of activity were detected in infected than in non-infected plants. The hypothesis that resistance in lines carrying Lr29 or Lr34 is related to higher levels of β-1,3-glucanase expression was not confirmed.