Transient GUS Expression in Decapitated Lentil Embryos

Lentil (Lens culinaris Medik.) is an important proteinand carbohydrate-rich food for many developing countries and is also popular in developed countries where they are perceived as a healthy component of the diet. Lentil seeds contain about 24.2% high quality protein, 60% carbohydrates and 2.4 4.2% mineral matter (Hulse 1994). Although lentil is one of the oldest cultivated crop plants, its agronomic performance is not better than a semi-domesticated species. The main constraints for lentil breeding and production are poor yield stability and high susceptibility to fungal diseases. Due to the rather narrow genetic base and lack of resistance genes against major fungal diseases in lentil conventional breeding methods cannot be applied for addressing these objectives. In this context the genetic transformation could be used to develop disease resistant plants. The grain legumes have been less amenable to manipulation in vitro (McClean and Grafton 1989), and generally are recalcitrant to transformation (DeKathen and Jacobsen 1990). Lentil is susceptible to tumor induction by Agrobacterium tumefaciens (Warkentin and McHughen 1991). Although lentil transformation using Agrobacterium (Warkentin and McHughen 1992, 1993) and particle gun bombardment have been reported (Öktem et al. 1999) there is no convincing report on an efficient and stable transformation system for this crop. The susceptibility of different lentil explants to various strains of Agrobacterium has been studied through transient GUS expression. Four lentil lines, ILL6994, ILL5883, ILL7201 and ILL7012 were obtained from the International Center for Agricultural Research in the Dry Areas (ICARDA), Aleppo, Syria and used in the present investigation. Seeds were soaked in 70% ethanol for one min and then surface sterilized with 6.0% commercial bleach for 5 min and afterwards washed three four times with sterilized distilled water. The surface sterilized seeds were cultured on water-agar medium and kept in dark at 21 ± 2oC until their germination.