STEADY-STATE LEVELS OF D1 PROTEIN AND PSBA TRANSCRIPT DURING UV-B INACTIVATION OF PHOTOSYSTEM-II IN WHEAT

UV-B induced alterations in the pigment composition and photosystem II (PS II) electron transport activity was studied in laboratory grown s eedlings of wheat cv. RR21. Subsequent to UV-B exposure, the chlorophy ll, carotenoids, anthocyanin and flavonoids, showed an increase in the ir levels. A time dependent decrease in the photosystem II electron tr ansport activity was evident in the UV-B treated plants. Reduction in the steady state levels of transcript of the psbA gene and its transla tion product the D1 protein was concurrent with the loss of PS II acti vity in the wheat plants exposed to UV-B.