Lic1, a new mutant affecting light signalling and clock function in Arabidopsis

SABRINA SANCHEZ; PAULA TONDI; PABLO CERDÁN; MARCELO YANOVSKY

Rosario, Argentina

Congreso; XLII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2006

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

  Circadian clocks allow plants to adjust multiple physiological and developmental processes in anticipation of daily and seasonal changes in the environment. A feedback loop composed of cycling gene products that control their own synthesis has been suggested as the central oscillatory mechanism. The clock is synchronized on a daily basis by light cycles perceived by phytochromes and cryptochromes, but the signalling pathway connecting these photoreceptors to the clock is largely ignored. We have conducted a high-throughput screening using Arabidopsis thaliana as a model system to identify novel components of the circadian signalling network. Here we report the identification of a novel mutant, lic1 (Light Input to the Clock 1), in which the circadian period of the rhythm of leaf movement is lengthened compared to the wild type. The lic1 mutant is also defective in light dependent responses across multiple wavelengths, suggesting that it may encode a component that integrates light signalling perceived through multiple photoreceptors into the clock. The regulation of flowering time is also disrupted in the lic1mutant, which flowers later than the wild-type. The pattern of expression of clock associated and flowering time genes in lic1 will be presented. Molecular mechanisms underlying the circadian and flowering time phenotypes will be discussed.