Factors Influencing GUS Expression in Cucumber (Cucumis sativus Linn.)

The transformation efticiency of two strains of Agrobacteril/lIl tlllllejaciells, EHA 105 and LBA 4404 with three cucumber cultivars, viz. Endeavor, Green Long and Poinsett 76 have been investigated. Factors such as age of explants, co-cultivation period, efticiency of strains, acetosyringone treatment, use of Kanamycin and Basta as selection agents were assessed. GUS histochemical assay was performed to assess transformation efticiency. 5-day-old cotyledons and 3-day co-cultivation period for Endeavor and Green Long and 2-day co-cultivation period for Poinsett 76 were suitable for ellicient transformation. EHA 105 was more virulent and the transformation elliciency was two to three folds higher than LBA 4404. Among the three cultivars, Endeavor was found to be more responsive to transformation as evidenced by GUS expression followed by Green Long and Poinsett 76. Acetosyringone (20 iJ.M50 iJ.M) enhanced the efticiency of transformation in all the three cultivars. Basta at 10 mgll was more efficient selection agent than Kanamycin at 100 mg/1. Shoot regeneration occurred within 6 weeks after co-cultivation.