Early light-inducible protein in pea is stable during light stress but is degraded during recovery at low light intensity

Abstract

The nuclear-encoded, thylakoid-bound early light-inducible protein (ELIP) reported to be related to the initial stages of chloroplast differentiation is synthesized in substantial amounts in leaves of mature plants exposed to light stress conditions (Adamska, I., Ohad, I., and Kloppstech, K. (1992b) Proc. Natl. Acad. Sci. U.S.A. 89, 2610-2613). Increase in ELIP content correlates with the photoinactivation of PSII, degradation of D1 protein, and changes in the level of pigments. Inhibition of phytoene desaturase and/or zeta-carotene desaturase during light stress drastically increases accumulation of the protein. ELIP mRNA is short-lived (t1/2 = 1 h). The thylakoid bound protein is stable in high light exposed leaves and is degraded only during recovery from light stress at low light intensity (40 microE/m2s). The lifetime of the protein during the recovery process increases with the extent of initial light stress condition. We propose that ELIP synthesis and degradation is related to the process of the plant response to light stress and recovery from photoinhibition.