PHOTOMORPHOGENIC MUTANTS OF TOMATO

Photomorphogenesis of tomato is being studied with the aid of mutants which are either modified in their photoreceptor composition or in the ir signal transduction chain(s). Several mutants affecting the phytoch rome family of photoreceptors, some of which appear deficient for spec ific genes encoding phytochrome apoproteins have been isolated. In add ition, other mutants, including transgenic lines overexpressing phytoc hrome A, exhibit exaggerated photomorphogenesis during de-etiolation. Anthocyanin biosynthesis and plastid development are being used as mod el systems for the dissection of the complex interactions among photom orphogenic photoreceptors and to elucidate the nature of their transdu ction chains.