Aims: The aim of the study was to evaluate the in vitro antibacterial effects of
glucosinolate hydrolysis products (GHP) against plant pathogenic micro-organisms
namely Agrobacterium tumefaciens, Erwinia chrysanthemi, Pseudomonas
cichorii, Pseudomonas tomato, Xanthomonas campestris and Xanthomonas
juglandis.
Methods and Results: Using a disc diffusion assay, seven different doses of 10
GHP were tested against each bacteria. The results showed that the isothiocyanates
were potent antibacterials, whilst the other GHP were much less efficient.
Moreover, the antibacterial effects were dose-dependent, increasing with the
dose applied; 2-phenylethylisothiocyanate and sulforaphane showed the strongest
inhibitory effects. The overall results show a great potential for using the
isothiocyanates as an alternative tool to control undesired bacterial growth in
plants.
Conclusions: Glucosinolate hydrolysis products and more specifically the
isothiocyanates: benzylisothiocyanate, 2-phenylethylisothiocyanate, the isothiocyanate
Mix and sulforaphane, were effective phytochemicals against the in vitro
growth of the phytopathogenic bacteria. The antibacterial activity exhibited by
these phytochemicals reinforces their potential as alternatives to the traditional
chemical control of phytopathogenic bacteria.
Significance and Impact of the Study: This current in vitro study is the first
providing comparative data on GHP as potential control agents for plant
pathogenic bacteria. However, more studies are needed to determine their
possible allelopathic impacts e.g. inhibition of plant growth and negative effects
on beneficial soil bacteria and fungi (mycorrhizae
