Detection of Antibacterial Activity from the Modified Storage Organs of Carrot (Daucus carota ssp. sativus (Hoffm.) Arcang. cv. Kuroda'), Radish (Raphanus sativus Linn. cv.，Snowy'/ "Long White') and Potato (Solanum tuberosum Linn. cv.，Granola')

Abstract

Plants have long been used as sources of crude antimicrobial compounds. Underground, modified storage organs such as tubers, enlarged taproots, and rhizomes are located in an environment with a high density of microorganisms capable of invasion and decomposition. These plant structures are equipped with numerous defense mechanisms in order to survive. The objective of this study was to detect antibacterial activity from the modified storage organs of S. tuberosum Linn. cv. 'Granola' (Potato), D. carota ssp. sativus (Hoffm.) Arcang. cv. 'Kuroda' (Carrot), and R. sativus Linn. cv. 'Snowy' / 'Long White， (Radish) against Staphyloccocciis aureus, Bacillus subtilis, and Escherichia coli. Pure, undiluted extracts were obtained by pressing grated samples in a presser and sterilized using Sartorius Minisart® NML Syringe Filters with pore sizes of 0.2jim. The sterilized extracts from the peelings and fleshy inner tissues of both freshly harvested and market- purchased potato tubers, carrot and radish roots were tested against S. aureus, B. subtilis, and E. coli via Disk Diffusion Assay. It was found that the medullary tissue extract of the market-purchased potatoes possessed antibacterial activity against S. aureus only. Nine isolates of endophytic bacteria from the market-bought potato were tested and did not show antibiosis against S. aureus. These results suggest that market-purchased potatoes may be a potential source of naturally occurring antibacterial compounds that are probably produced by the plant and not by the endophytic bacteria.