ABSTRACT
Cichorium intybus L. (Asteraceae) is a popu lar crop that provides a variety of edible products from both leaves and storage roots. N utritional aspects such as hypocaloric value, h igh fibre, vitam in and m ineral salt content increase the im portance of chicory for the d iet of hum an beings in developed countries. In addition, chicory is interesting from an agronomic po in t of view because of the low term inal in p u t required. Chicory is com m only used as salad and som e varieties are cultivated for their sweet roots which, w hen roasted, become a coffee substitute. The chicory pow der
increases the volume of coffee and improves the flavour. Added to coffee, it counteracts caffeine and helps in digestion. A tea made from chicory is beneficial in curing an upset stomach. In addition, chicory is a potential industrial crop for the production of fructose syrup from its roots. In traditional system of medicine, the plant is used for the treatment of diseases like jaundice, gout and rheumatism. Chicory (Cichorium intybus L.) has been regenerated from primary explants such as storage roots (Margara and Rancillac 1966), green leaves (Toponi 1963), etiolated leaves (Vasseur 1979b), floral stems (Bouriquet and Vasseur 1973), suspension cultures (Yassseen and Splittstoesser 1995), leaf and petiole (Eung et al., 1999), leaf midrib (Mix-Wagner and Eneva T, 1998), leaf (Mix-Wagner and Eneva T, 1996), pollen (Castano and De Proft, 2000) and protoplasts (Varotto et al., 1997; Binding et al., 1981: Crepy et al., 1982; Saski et al., 1986). Plants have also been regenerated from tissue cultures of mature tap roots (Heirwiegh et al., 1985). A regeneration protocol from the leaf explants has earlier been described by Vermeulen et al., (1992) and Genga et al., (1994). Inspite of these regeneration protocols published, there is an urgent need to develop an efficient regeneration protocol of chicory for its genetic transformation since with current protocols, the number and dimension of regenerated shoots generated and their height achieved with earlier protocols were not appropriate for genetic transformation experiments. Hence, this study was conducted to develop an efficient regeneration protocol for in vitro culture of Cichorium intybus L. and an Agrobacterium tumefaciens mediated genetic transformation technique, in order to integrate osmotin gene in the genome of chicory plant, inducing osmotin protein so that it became resistant/tolerant to drought and salt stress. The gene product, osmotin, is a 24 KD protein, and originally isolated from tobacco cells adapted to NaCl stress and desiccation. The stress-induced synthesis and accumulation of the osmotin protein is correlated with osmotic adjustment in tobacco cells. The overexpression of osmotin gene in transgenic tobacco has been reported to impart tolerance against both salinity and drought stress (Barthakur et al., 2001). It is, therefore, expected that chicory plants carrying osmotin gene will also tolerate both salinity and water stress. Hence, these plants can be profitably cultivated in saline and rainfed areas of the country.
