Qualitative and quantitative differences in the light harvesting complexesof photosystem II (LHCII) between a chlorophyll-less barley mutant "NYB" and its wild type

A comparative study on chloroplast ultrastructure and light harvesting comp lexes of photosystem II (LHCII) was made between a new barley mutant <<NYB> > and its wild type. As compared with the wild type, NYB chloroplasts posse ss less thylakoids and grana stacks. Green gel electrophoresis showed that the LHCII of mutant barley decreased markedly, while the levels of other PS II-antenna were almost the same as that of the wild barley. There was a lar ger decrease in the mutant in the antenna size of PSII than that of PSI. SD S-PAGE analysis showed that the apoproteins of LHCII greatly declined in th e mutant. The use of immunoblotting further revealed that the 26kD componen t of LHCII was depleted in thylakoid membranes of NYB. Northern blot analys is with a specific cab gene probe showed that there was no appreciable diff erence in the LHCII mRNA level between the wild and mutant barley, indicati ng that the decreased LHCII level in mutant barley is not due to a reduced transcription or accumulation of its mRNA. The possible mechanism responsib le for the low abundance of LHCII in mutant barley is discussed.