This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Web of Science (8) Citing Articles via Google Scholar Google Scholar Articles by Chia, C. P. Articles by Arntzen, C. J. Search for Related Content PubMed PubMed Citation Articles by Chia, C. P. Articles by Arntzen, C. J. Agricola Articles by Chia, C. P. Articles by Arntzen, C. J.

Articles

Developmental Loss of Photosystem II Activity and Structure in a Chloroplast-Encoded Tobacco Mutant, Lutescens-1¹

MSU/DOE Plant Research Laboratory, Michigan State University, E. Lansing, Michigan 48824-1312, E. I. du Pont de Nemours, Central Research and Development, Wilmington, Delaware 19898

Lutescens-1, a tobacco mutant with a maternally inherited dysfunction, displayed an unusual developmental phenotype. In vivo measurement of chlorophyll fluorescence revealed deterioration in photosystem II (PSII) function as leaves expanded. Analysis of thylakoid membrane proteins by polyacrylamide gel electrophoresis indicated the physical loss of nuclear- and chloroplast-encoded polypeptides comprising the PSII core complex concomitant with loss of activity. Freeze fracture electron micrographs of mutant thylakoids showed a reduced density, compared to wild type, of the EF_s particles which have been shown previously to be the structural entity containing PSII core complexes and associated pigment-proteins. The selective loss of PSII cores from thylakoids resulted in a higher ratio of antenna chlorophyll to reaction centers and an altered 77 K chlorophyll fluorescence emission spectra; these data are interpreted to indicate functional isolation of light-harvesting chlorophyll a/b complexes in the absence of PSII centers. Examination of PSII reaction centers (which were present at lower levels in mutant membranes) by monitoring the light-dependent phosphorylation of PSII polypeptides and flash-induced O₂ evolution patterns demonstrated that the PSII cores which were assembled in mutant thylakoids were functionally identical to those of wild type. We conclude that the lutescens-1 mutation affected the correct stoichiometry of PSII centers, in relation to other membrane constituents, by disrupting the proper assembly and maintenance of PSII complexes in lutescens-1 thylakoid membranes.

³ Current address: Biotechnology Research, CIBA-GEIGY Corp., P. O. Box 12257, Research Triangle Park, NC 27709-2257.

¹ Supported, in part, by Department of Energy Contract No. DE-AC02-76ERO-1338 to Michigan State University and a grant from E. I. du Pont de Nemours, Inc. C. P. C. received partial support from a United States Office of Education Graduate and Professionals Opportunities Program Fellowship.