Qualitative and Quantitative Differences in the Light Harvesting Complexes of Photosystem II (LHC II) between a Chlorophyll-less Barley Mutant «NYB» and Its Wild Type

Abstract

A comparative study on chloroplast ultrastructure and light harvesting complexes of photosystem II (LHCII) was made between a new barley mutant « NYB » and its wild type. As compared with the wild type, NYB chloroplasts possess less thylakoids and grana stacks. Green gel electrophoresis showed that the LHCII of mutant barley decreased markedly, while the levels of other PSII-antenna were almost the same as that of the wild barley. There was a larger decrease in the mutant in the antenna size of PSII than that of PSI. SDS-PAGE analysis showed that the apoproteins of LHCII greatly declined in the mutant. The use of immunoblotting further revealed that the 26 kD component of LHCII was depleted in thylakoid membranes of NYB . Northern blot analysis with a specific cab gene probe showed that there was no appreciable difference in the LHCII mRNA level between the wild and mutant barley, indicating that the decreased LHCII level in mutant barley is not due to a reduced transcription or accumulation of its mRNA. The possible mechanism responsible for the low abundance of LHCII in mutant barley is discussed.