Abstract
Pectobacterium carotovorum is the most common causative organism of bacterial soft rot which gives rise to great economic losses. It is important to implement disease control measures and management strategies on this bacterium in order to prevent further crop loss. Among the various management strategies, using the antibacterial nature of spices offer promising solutions to pesticidal hazards and also to increasing cost of plant protection operations. Although there are many reports on the antibacterial nature of spices on various pathogens, its effect on P. carotovorum is limited. Objectives of this study were to determine the antimicrobial activity of selected spices and then to ascertain the minimum inhibitory concentration (MIC) of aqueous and ethanolic extracts of those spices against P. carotovorum. Among the nine tested spices, four were active against P. caratovorum. As depicted by agar well diffusion assay, the highest inhibitory effect on P. carotovorum was shown by the aqueous and ethanol extracts of Allium sativum while the aqueous and ethanolic extracts of Cinnamomum verum gave the smallest zones of inhibition. Garcinia cowa and Tamarindus indica displayed moderate antibacterial activity. There was no significant difference (p>0.05) in inhibition zones between aqueous and ethanol extract of a particular spice. MIC of the spices, which inhibited the growth of P. carotovorum was 0.5 g/ml within the test range. Positive extracts can be used as a cost effective and eco-friendly preventive strategy to minimize the effects of P. carotovorum. Evaluation of the antibacterial activity of these extracts under field conditions is necessary before a cost-effective formulation is developed.
Highlights
Plant associated diseases are the main constraints in crop cultivation which leads to significant reduction in yield and product quality
Bacterial soft rot caused by Pectobacterium carotovorum
Pathogenicity of P. carotovorum is known to be through secretion of exoenzymes such as pectinases leading to degradation of the fleshy parts of the plants ranging from root of carrots to leafy green vegetables such as lettuce
Summary
Plant associated diseases are the main constraints in crop cultivation which leads to significant reduction in yield and product quality. P. carotovorum is a Gram negative, soil borne opportunistic phytopathogen which macerates plant tissues using its pectolytic ability This bacterium has been classified under the family Enterobacteriaceae (Perombelon 1990) where many phyto and human pathogens are included. The pathogen and disease management is mainly through cultural and chemical strategies (Feldberg et al, 1988; Wright et al, 2005; Paradza et al, 2012) These various management strategies confer innumerable problems such as pesticidal hazards, environmental pollution, pesticide residues in crops and ever growing cost of the plant protection operations. The aroma and flavour, the antimicrobial activity of spices is governed by these phytochemicals that act as phyto-protectants in plants (Joe et al, 2009). Bioactive compounds such as isoflavones, anthocyanins, flavonoids (Chang 1988; Joe et al, 2009) are found in spices
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
