9305037 Maliga The proposed research is on the general area of nucleocytoplasmic interactions: The objective is to identify nuclear genes that control the expression of single Arabidopsis thaliana plastid genes. Specific objectives of the research are: (i) Clone and sequence the plastid rbcL and psbA regions from Arabidopsis. (ii) Test expression of reporter genes encoding B- glucuronidase and luciferase under control of psbA regulatory sequences. (iii) Arabidopsis seed mutagenesis and screening of M2 seedlings for nuclear mutants with altered reporter gene (uidA, luc) expression. (iv) Established complementation groups, determine map position of mutations. *** Through the project, methods will be developed for the manipulation of the Arabidopsis plastid genome so that plastid molecular biology and genetics can also benefit from this model system. %%%