Differences in in vitro plant regeneration ability among four Arabidopsis thaliana ecotypes

Abstract

The Arabidopsis ecotypes Columbia (Col), Landsberg erecta (Ler), Cape Verde Island (Cvi) and Wassilewskija (WS) have been tested for their regeneration response in vitro. A characteristic morphology of leaf-derived calluses has been found for each ecotype. Differences in regeneration ability have been detected depending on the plant strain. the explant source and on the culture medium composition. In CIR/SIR media, which contain 0.5 mg l−1 (2.26 μM) of 2,4-dichlorophenoxyacetic acid (2,4-D) and glucose, root explants from the four ecotypes are able to reach a considerable regeneration level, while leaf explants do not regenerate beyond a basal level (5% approximately). In CIH/SIH media, which contain 2.2 mg l−1 (9.95 μM) of 2,4-D and suerose, leaf explants from all the ecotypes, with the exception of Col, are able to regenerate, but they do it at variable levels (Ler 5.75%, WS 75.09%, and Cvi 27.53% as regeneration rates). With these media all root explants are able to regenerate, but again the four ecotypes show different rates (Col 27.7%, Ler 57.25%, WS 98.54%, and Cvi 42.25%). The variation of the different medium components affects differentially the regeneration ability of the four ecotypes depending also on the kind of explant. Thus, when the 2,4-D concentration is raised WS duplicates its regeneration rate in both leaf and root explants. Changing glucose for sucrose in CIR/SIR media diminishes to the basal level the regeneration of Cvi root explants, while the CIH/SIH salts and vitamin concentration permit the regeneration of leaf explants from all the ecotypes except Col. The genes responsible for those observed differences in regeneration ability could be identified and mapped by analyzing the in vitro regeneration behavior of the recombinant inbred lines (RILs) obtained by crossing these ecotypes.