Sesame (Sesamum indicum L.) is one of the oldest cultivated oilseed plants. The crop is grown mainly in tropical and subtropical countries in Asia, Africa and South America. Diseases and insect pests pose limits to economic production. Because sesame is only a minor crop in countries with industrialized agriculture, the development of chemical protection has been neglected. For example, no pesticides are currently approved for sesame in the U.S.A.

Natural products of sesame have been attracting the attention of chemists for two reasons. Firstly, since ancient times sesame has been valued as a health food additive, preventing disease and promoting well being, particularly in Asia. Compounds believed to be responsible for these beneficial health effects are antioxidants and lignans. Their potential as nutraceuticals and pharmaceuticals has not been exploited yet. Secondly, sesame oil contains metabolites with methylenedioxyphenyl moiety which dramatically increase the potency of certain insecticides because they inhibit enzymes involved in the detoxification of insecticides by target pests.

Sesame produces a range of other metabolites that may act as resistance factors, not only against insects but also against fungal diseases. For example, sesamol inhibits the growth of several species of fungi and chlorosesamone shows antifungal activity toward Cladosporium fulvum.

 

Objective

The aim of the project is to systematically investigate secondary metabolites in sesame by HPLP-MS/MS, relate these results to the genetic relationship among accessions and cultivars (revealed by genome fingerprinting) and finaly assess the potential of secondary metabolites in sesame as resistance factors against diseases and pests. The project relies on the combination of DNA fingerprinting by AFLP, metabolic analysis by HPLC-MS and bioassays with fungal pathogens and whitefly.

Hernan's results from this project have so far been published in these contributions:

• Laurentin H and Karlovsky P (2007): AFLP fingerprinting of sesame (Sesamum indicum L.) cultivars: identification, genetic relationship and comparison of AFLP informativeness parameters. Genetic Resources and Crop Evolution, in press.
• Laurentin H and Karlovsky P (2006): Genetic relationship and diversity in sesame (Sesamum indicum L.) germplasm collection using amplified fragments length polymorphisms (AFLP). BMC Genetics 7:10
• Laurentin H, Karlovsky P (2006) : Untersuchung der genetischen und metabolischen Diversität in einer Sammlung von Sesam-Akzessionen. 55. Deutsche Pflanzenschutztagung, 25.-28.9.2006. In: Mitteilungen aus der BBA 400:267-268.
• Laurentin H and Karlovsky P (2005): Investigation of genetic variability among twenty sesame (Sesamum Indicum L.) Venezuelan cultivars using amplified fragments length polymorphisms (AFLP). Proceedings of the Deutscher Tropentag, October 11-13, 2005, Hohenheim (Germany).
• H. Laurentin, A. Ratzinger and P. Karlovsky (2005): Relationship between genetic and metabolic diversity in sesame (Sesamum indicum L.) . 2nd International Symposium on Recent Advances in Food Analysis, Prague 2005, Book of Abstracts, Last Minute Posters p. 16.
• U. Hettwer, H Laurentin and P. Karlovsky:DETERMINATION OF ANTIOXIDATIVE FUROFURAN LIGNANS IN SESAME SEEDS BY HPLC-MS. 2nd International Symposium on Recent Advances in Food Analysis, Prague 2005, Book of Abstracts, Last Minute Posters p. 15.

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