Mechanismen der pflanzlichen Entwicklung: Die Rolle der Steroide in der Embryogenese von Arabidopsis

• Applicant: Professorin Dr. Kathrin Schrick
• Subject Area: Plant Cell and Developmental Biology
• Term: from 2002 to 2005
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5384267

Embryogenesis in Arabidopsis is a stereotyped developmental process that is orchestrated through the functions of specific genes. Three mutants, cephalopod (cph), fackel (fk) and hydral (hydl), lack normal cell morphology and show defects in pattern formation during embryonic development. The corresponding genes encode sterol biosynthesis enzymes: CPH, a C-24 methyltransferase; FK, a C-14 reductase; and HYD1, a C-8,7 isomerase. These findings suggest that steroid molecules play critical roles in early plant development. In animal cells, cholesterol is important for the integrity of the cell membranes and in addition serves as a percursor for steroid hormones required in embryogenesis. The only plant steroid hormones identified thus far are the brassinosteroids (BRs), which are needed for postembryonic cell expansion, but have not been shown to be required for cell morphogenesis in embryonic development. The projects described in this proposal probe the role of steroid biosynthesis in plants via protein localization studies of CPH, FK and HYD1. Further, the function of START, a candidate domain for sterol-binding found in a subclass of plant homeodomain-leucine zipper transcription factors, will be examined for a putative role in sterol signal transduction.

• DFG Programme: Research Grants