Early induced protein 1 (PrELIP1) and other photosynthetic, stress and epigenetic regulation genes are involved in Pinus radiata D. don UV-B radiation response

The continuous atmospheric and environmental deterioration is likely to increase, among others, the influx of ultraviolet B (UV-B) radiation. The plants have photoprotective responses, which are complex mechanisms involving different physiological responses, to avoid the damages caused by this radiation that may lead to plant death. We have studied the adaptive responses to UV-B in Pinus radiata, given the importance of this species in conifer forests and reforestation programs. We analyzed the photosynthetic activity, pigments content, and gene expression of candidate genes related to photosynthesis, stress and gene regulation in needles exposed to UV-B during a 96 h time course. The results reveal a clear increase of pigments under UV-B stress while photosynthetic activity decreased. The expression levels of the studied genes drastically changed after UV-B exposure, were stress related genes were upregulated while photosynthesis (RBCA and RBCS) and epigenetic regulation were downregulated (MSI1, CSDP2, SHM4). The novel gene PrELIP1, fully sequenced for this work, was upregulated and expressed mainly in the palisade parenchyma of needles. This gene has conserved domains related to the dissipation of the UV-B radiation that give to this protein a key role during photoprotection response of the needles in Pinus radiata.