A MOLECULAR CHARACTERIZATION OF THE CHLOROPLAST GENOME OF THE BRYOPHYTE PHYSCOMITRELLA PATENS (HEDW.) BSG (MOSS, GENE-MAPPING)

A restriction endonuclease cleavage site map for the enzymes Cla I and Bgl II has been constructed, by filter hybridizations using purified Cla I restriction fragments as hybridization probes, for the chloroplast genome of a bryophyte, the moss Physcomitrella patens (Hedw.) BSG. The plastid chromosome contains approximately 122 kb organized into a small (17 kb) and a large (81 kb) single copy region separated by two copies of a repeat sequence (12 kb) oriented in an inverted arrangement. The following genes have been mapped using heterologous probes from corn, spinach, pea, and petunia: the 16S and 23S rRNA genes; the ribosomal protein genes rpl 2 and rps 19; the ATP synthase subunit genes atp A, B, E, H, and F; the Photosystem I P700 chlorophyll apoprotein genes psa Al and psa A2; the cytochrome f (pet A), cytochrome b6 (pet B), and subunit 4 of the cytochrome b/f complex (pet D) genes; the gene encoding the large subunit of ribulose-1, 5-bisphosphate carboxylase/oxygenase (rbc L); and the genes for the Photosystem II 32 kD herbicide binding protein (psb A), the 51 kD and the 44 kD herbicide binding proteins (psb A), the 51 kD and the 44 kD chlorophyll a binding proteins (psb B and psb C), the "D-2" protein (psb D), and cytochrome f (psb E). With the exception of a 20 kb inversion bordered internally by psb A and atp H, the general order and arrangement of the moss chloroplast genes are very similar to the consensus angiosperm chloroplast genome typified by that of spinach. In the moss chloroplast genome, as in the majority of the angiosperm chloroplast genomes, there is a correlation between the presence of an inverted repeat structure and a highly conserved gene order.