Assessment of the efficiency of various gene promoters via biolistics in leaf and regenerating seed callus of millets, Eleusine coracana and Echinochloa crusgalli

Abstract

A simple regeneration protocol has been developed for two millets, Eleusine coracana and Echinochloa crusgalli. The plantlet regeneration in both the millets is via somatic embryogenesis as evidenced by histological studies. In the case of E. coracana, up to 340 plants could be regenerated per 100 seed calli while up to 2266 plants could be regenerated per 100 seed calli of E. crusgalli. Subsequently, the regenerating seed callus as well as leaf segments from these two millets have been used as explants for assessing the suitability of five gene promoter constructs for transformation via biolistic means. Transient GUS histochemical as well as spectrofluorometric assays reveal the high efficiency of Ubiquitin I gene promoter from maize in terms of bringing about maximum GUS activity in both the millets. The activity of Ubiquitin I promoter from maize was highest in leaf lamina followed by leaf sheath and seed callus. Other four promoters were found to be much less efficient for both millets.