Natural variation in Arabidopsis seedling photomorphogenesis reveals a likely role for TED1 in phytochrome signalling

Abstract

Natural genetic variation present among accessions of Arabidopsis thaliana (L.) Heynh. (commonly referred to as 'ecotypes') is a valuable, yet under-exploited genetic resource for the study of plant developmental, physiological, and evolutionary responses to the environment. Seedling photomorphogenic responses were surveyed in a set of 11 Arabidopsis accessions collected from a variety of edaphic habitats and geographic locations. We observed substantial variation in light-dependent hypocotyl growth responses in a variety of light conditions (white, red, blue, far-red enriched light). The genetic basis for differences in hypocotyl growth responses to light between the Columbia (Col-0) and Bensheim (Be-0) accessions was examined in an F2 population. Quantitative genetic and quantitative trait locus (QTL) analyses were consistent with a model in which differences in light responses were conditioned by a single major gene with semi-dominant effect, located on chromosome 4. Further experiments suggested that the genetic difference governing hypocotyl variation in this cross may be allelic to ted1, an extragenic suppressor of the de-etiolated mutant det1, that was identified as an ethylmethane sulphonate-induced mutation. This finding supports a role for ted1 in photomorphogenic signalling.