ELICITATION OF THIOPHENE PRODUCTION BY HAIRY ROOTS OF TAGETES-PATULA

Various biotic and abiotic elicitors were assayed for their effects on thiophene production by hairy roots of Tagetes patula. The biotic elicitors tested were extracts of the fungi Aspergillus niger, Fusarium oxysporum, Penicillium expansum, and Phytophthora megasperma, of the bacteria Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus, and yeast extract. The abiotic stress factors were the addition of calcium ions to the medium. Ethephon (a precursor of ethene), and a high pH. In general, the biotic elicitors were effective, although the extent to which elicitation occurred differed from elicitor to elicitor. The highest production increase was attained with the extract of Aspergillus niger, an increase of 85% compared to the control. Only yeast extract had no positive effect on thiophene production. The abiotic elicitors tested had only small effects on thiophene production: the calcium ions induced a slight increase, the Ethephon only had a negative effect on production, and the high pH yielded a temporarily high concentration but the roots were no longer viable after this treatment.