UV light stress induces the synthesis of the early light-inducible protein and prevents its degradation.

ELIP is a nuclear-encoded protein localized in the thylakoid membranes. The protein is specifically induced by blue light in mature, light-grown plants (Adamska, I., Ohad, I., and Kloppstech, K. (1992) Proc. Natl. Acad. Sci. U. S. A. 89, 2610-2613), as well as in plants developed in the light in which pigment synthesis and plastid development were inhibited by the bleaching herbicide norflurazon. ELIP transcription and protein accumulation are induced also by UVA but not by UVB light. However, UVB light allows ELIP synthesis induced by superimposed white light. The protein is stable under light stress including UVA and UVB light, but it is rapidly degraded upon cessation of the light stress conditions. ELIP synthesis and integration into the chloroplast membranes is related neither to chloroplast translation activity nor to photosynthetic electron flow. Inhibition of carotenoid synthesis by fluridone, a bleaching herbicide which causes extensive damage to the photosynthetic apparatus, does not affect induction of ELIP transcription during light stress but greatly enhances ELIP accumulation. Based on these results it is proposed that ELIP turnover is related to the light stress and recovery process in plants.