Induction of Systemic Resistance in Persea bombycina Against Pestalotiopsis disseminata Using Bioinoculants

Among eight different morphotypes (S1-S8) of Persea bombycina, locally known as som plant, screened for resistance against Pestalotiopsis disseminata causing grey blight disease, S5morphotype was found to be highly susceptible under field conditions.Immunodetection of P. disseminata in leaf tissue using Polyclonal antibody raised against the pathogen has been demonstrated following various immunological formats such as immunodiffusion, dot immunobinding assay, plate trapped antigen (PTA) coated enzyme linked immunosorbent assay (ELISA) and indirect immunofluorescence.Immunogold localization of grey blight pathogen (P.disseminata) in som leaf tissue using transmission electron microscopy has been demonstrated for the first time for this host-pathogen system .Strategies for induction of immunity in som plants (S5 morphotype) against P. disseminata using bioinoculants such as PGPF (Trichoderma asperellum), AMF (Rhizophagus fasciculatus) and PGPR (Bacillus pumilus) alone or in combinations have been developed.Plant growth promotion and reduction in disease severity were evident following application of bioinoculants.Significant increase in defense enzymes such as chitinase (CHT), β-1,3 glucanase (GLU), phenylalanine ammonia-lyase (PAL) and peroxidase (POX) were observed in both roots and leaves following the application of bioinoculants.Cellular localization of chitinase and glucanase in leaf and root tissue following induced immunity against grey blight pathogen using PAbs of chitinase and glucanase have been demonstrated by indirect immunofluorescence and immunogold labelling.It is clearly evident that the applications of bioinoculants greatly improved the health status of som plants (S5) and also induced systemic resistance in the plant against grey blight pathogen.