Role of Plant Growth Regulators in The interaction Between Phytopathogenicity of Sclerotinia Sclerotiorum and Their Host Plants

The effect of synthetic plant growth regulators (PGRs) on Sclerotinia sclerotiorum was investigated in vitro and in vivo, on plants. The results showed that naphthalene acetic acid (NAA) has a potential to inhibit fungus in vitro and in vivo. It reduced white mold disease severity on bean and cucumber plants at concentrations up to 500, u.g/ml active ingredient. Ethephon and gibberellic acid (GA3) promoted both mycelium growth rate and white mold disease severity on plants at concentrations up to 400 /seg/ml. Methyl jasmonate (MeJA), and absiscic acid (ABA) decreased mycelium growth of the fungus in vitro. MeJA decreased bean and cucumber white mold disease at concentrations up to 250 /4,g/ml. ABA increased disease development on bean and cucumber plants at concentrations up to 300 /Lg/Hll. Aminoethoxvinyleglycine (AVG) used as an ethylene-inhibitor agent significantly inhibited white mold lesions development in vivo and decreased white mold disease severity on bean and cucumber plants at concentrations up to 300 /,Lg/ml. Ethylene was produced by the fungus S. sclerotiorum when grown on shaking PDB medium amended with 10 mM methionine at a rate of 400 M1/g/h.