Agrobacterium-mediated transformation of Amaranthus hypochondriacus: light- and tissue-specific expression of a pea chlorophyll a/b-binding protein promoter.

Mature embryos of Amaranthus hypochondriacus (amaranth) were used to develop an in vitro culture system for plant regeneration and genetic transformation. Plants were regenerated from embryo-derived callus cultivated on Murashige and Skoog medium supplemented with 10 µM 2,4-dichlorophenoxyacetic acid or 3,6-dichloro-2-methoxybenzoic acid and 10% coconut liquid endosperm. Transgenic plants were obtained by inoculation of mature embryo explants with a disarmed Agrobacterium strain containing the plasmid pGV2260(pEsc4), which carried the genes encoding neomycin phosphotransferase type II and β-glucuronidase. The presence of transgenes in the genome of transformed amaranth plants and their progeny was demonstrated by Southern blot hybridization. Tissue specific and light-inducible expression directed by a pea chlorophyll a/b-binding protein promoter was observed in transgenic amaranth plants and their progeny.