The expression of early light-inducible proteins (ELIPs) under high-light stress as defense marker in Northern- and Southern European cultivars of barley (Hordeum vulgare)

Clones coding for the two small early light-inducible proteins (ELIP)-gene families of 13.5 and 17 kDa have been used as markers to study the effect of high-light intensities on gene expression in cultivars of barley which were bred for growth in Southern and Northern Europe, The mRNA levels of the light-harvesting chlorophyll alb protein (LHC-IT) and the small subunit of ribulose-1,5-bisphosphate carhoxylase (SSU) were determined in addition. These data were correlated to the decay of PSII activity during high-light stress and its recovery, In all cultivars, the induction of ELIP mRNAs by high light was accompanied by a correspondent reduction of the LHC-II mRNA level, Furthermore, the LHC-II mRNA levels observed under low-light conditions used for the growth of the plants, were in all cases found to be inversely related to the amount of the FLIP which could be induced by a high-light treatment. In contrast, the amount of the SSU mRNA was reduced only at the highest investigated light intensity of 2000 pmol m(-2) s(-1). During recovery from light-stress, the activity of PSII was quickly restored in all European cultivars, Of these cultivars, however, the cv. Otis which expressed the highest ELIP levels recovered considerably faster than the cultivar p4266N which accumulated the lowest amounts of FLIP under high light, Thus, it appears likely that ELIPs contribute to the restoration of PSII activity during and after photoinhibition,