Induction of phenylpropanoid metabolism by Pseudomonas fluorescens against tomato spotted wilt virus in tomato.

Pseudomonas fluorescens (two native strains, one collection strain and their strain mixtures in all possible combinations) when applied through seed, seedling dip, soil and on leaf significantly reduced the tomato spotted wilt virus (TSWV) disease. In P. fluorescens-treated plants, the peroxidase and phenylalanine ammonia-lyase activity increased. Accumulation of phenolic compounds and lignin were shown to be increased in the P. fluorescens-treated plants. Isoperoxidase native PAGE indicated that the peroxidase isoforms in tomato plants induced by fluorescent pseudomonads were different from the control plants; this suggests that the general phenylpropanoid pathway is probably stimulated in tomato plants treated which in turn led to significant reduction in TSWV.