Dr Enrique Lopez-Juez Lecturer in Plant Molecular Biology School of Biological Sciences Royal Holloway, University of London Egham, Surrey, TW20 0EX United Kingdom Tel: 01784-443951 Fax: 01784-470756 E-mail: e.lopez@rhul.ac.uk Laboratory web site (details, images and further links) BBSRC (research sponsor) BS2020 (resources for 2nd year Plant Life... course) Light and the control of chloroplast development in Arabidopsis Plants require light as their energy source for growth, and therefore need to optimise light capture. They do so by sensing their light environment and modifying their development, particularly chloroplast development, accordingly. Chloroplasts do not develop in the dark in flowering plants. A primary controller of chloroplast biogenesis is the phytochrome photoreceptor family, and takes place at the level of expression of nuclear (and plastidic) genes which encode chloroplast proteins. We are studying how phytochrome controls the expression of photosynthetic genes. We are using for this a combined genetic and molecular approach in the model plant species Arabidopsis, whose genome is fully sequenced. The plastids also need to be functional for photosynthetic nuclear genes to be expressed. This implies the existence of a "plastid signal" which carries information from plastids to the nucleus. And this "plastid-functionality signal" is not the only other regulator of photosynthetic gene expression. Signals generated by the quantity of light that the leaf experiences also have effects on chloroplast (in indeed leaf) development. This light quantity sensor may be related to chloroplast metabolism (be a photosynthetic signal) or be a separate photoreceptor. Our evidence indicates both types of fluence rate sensor actually occur. We are trying to understand how each of these signals leads to chloroplast biogenesis, and how they interact. For further details please visit our laboratory web page G. VINTI, A. HILLS, S. CAMPBELL, J.R. BOWYER, N. MOCHIZUKI, J. CHORY AND E. LOPEZ-JUEZ (2000). Interactions between hy1 and gun mutants of Arabidopsis, and their implications for plastid/nuclear signalling. Plant J. 24: 883-894. [View abstract] E. WESTON, K. THOROGOOD, G. VINTI AND E. LOPEZ-JUEZ (2000). Light quantity controls leaf-cell and chloroplast development in Arabidopsis thaliana wild type and blue light-perception mutants. Planta 211: 807-815. [View abstract] K. PYKE and E. LOPEZ-JUEZ (1999). Cellular differentiation and leaf morphogenesis in Arabidopsis. CRC Critical Reviews in Plant Science 18: 527-546. [View abstract] E. LOPEZ-JUEZ, C.E. BAYNTON, A.M. PAGE, K.A. PYKE, S. ROBERTSON, G. VINTI (1999) Multiple light and plastid signals control chloroplast development in Arabidopsis. In Photosynthesis: Mechanisms and Effects (G. Garab, ed.) Kluwer, Dordrecht, pp 2805-2808 E. LOPEZ-JUEZ, R.P. JARVIS, A. TAKEUCHI, A. PAGE AND J. CHORY (1998). New Arabidopsis CAB-underexpressed (cue) mutants suggest a role for plastids in the regulation of nuclear gene expression by light. Plant Physiol. 118: 803-815. [View abstract] E. Lopez-Juez, S. Streatfield and J. Chory (1996). Light signals and autoregulated chloroplast development. In Light regulation of Plant Development (W.R. Briggs, R.L. Heath and E.M. Tobin) ASPP Symposium Series. p. 144-152 E. Lopez-Juez, M. Kobayashi, A. Sakurai, Y. Kamiya and R.E. Kendrick (1995). Phytochrome, gibberellins and hypocotyl growth: a study using the cucumber long hypocotyl mutant. Plant Physiology 107, 131-140 E. Lopez-Juez and M. Hughes (1995) Effect of blue light and red light on the control of chloroplast acclimation of light-grown pea leaves to increased fluence rates. Photochem. Photobiol. 61: 106-111 ©RHUL -