Abstract
The sessile nature of plants has made them rely upon their surrounding environment, such as light, gravity, temperature, and moisture. Among those environment factor, light is one of the most important element. Plants orientate their growth with respect to the direction of light (phototropism) or gravity (gravitropism). It has widely recognized that phototropism of Arabidopsis seedlings is subject to blue-light. We isolated an Arabidopsis mutant, which represents bended hypocotyls under red-light condition. The mutant, designated as flabby, showed normal phototropism by blue-light, and gravitropism, suggesting that there is dependent deviation control by red light. Fine mapping was used to identify flabby gene, and revealed that FLABBY encodes one of the gene family of ABC transporter, AtMDR1. AtMDR1, a homolog of multi-drug resistance gene of animals regulates auxin transport in Arabidopsis as previously reported. We discussed about the function of FLABBY on hypocotyl bending under red light.
