Long-term depletion of the stratospheric ozone layer contributes to an increase in terrestrial solar ultraviolet-B radiation. When exposed to elevated ultraviolet-B radiation (280-315 nm), plants display a wide variety of physiological and morphological responses. In this work, starting from previous microarray dataset used to assess transcriptome changes in Populus alba L. under UV-B radiation, we analysed the differential response of 5 poplar genotypes selected along a latitudinal and altitudinal gradient. Three years old rooted plants were acclimated in two identical phytotrons, except the presence of aUVBlamp array in just one of them. Inorder to simulate an environmental condition, plants were treated for 16 hours with an UVBbe (UVB biologically effective radiation) supplementary dose of 6 KJ/m2/day and allowed to recover during the night (8 hours). After plants were first adapted for 30 min in total darkness, chlorophyll fluorescence of PSII was measured. The ecophysiological data showed a decrease of the maximum efficiency of the PSII in the stressed plants, in particular for 3 clones, during the hours of the UVB treatment. We studied also, the association between polymorphism data (SNP) and expression level on genes (such as chs, comt, rbcl, and photolyase) putatively related to UV-B response. The leaf tissue of the 5 genotypes were sampled after treatment for 3, 6, 12 and 36 hours with UVB, and were analyzed using qRTPCR. Chs gene show high expression levels after 12 (3 genotypes) and 36 hours (1 genotype) of treatment, while comt gene show high levels of expression after 12 hours (4 genotypes) of treatment. Instead, photolyase gene show high levels of transcription just after 3 hours (1 genotype) of treatment and later his expression levels decreases. The qRT-PCR data show that there is not a significant difference of expression patterns for rbcL among the genotypes with a decrease that is consistent with the eco-physiological results. The results showed a different pattern of expression, with a dissimilar response among the clones analyzed towards the stress. Must still be clarified the association between the ecophysiological and expression data, with the sequences polymorphism analysis because of the absence of missense mutations.
Different gene expression pattern of Populus alba L. genotypes under elevated UV-B radiation
Ilaria Spanu;GiovanniEmiliani;Cristina Vettori
2010
Abstract
Long-term depletion of the stratospheric ozone layer contributes to an increase in terrestrial solar ultraviolet-B radiation. When exposed to elevated ultraviolet-B radiation (280-315 nm), plants display a wide variety of physiological and morphological responses. In this work, starting from previous microarray dataset used to assess transcriptome changes in Populus alba L. under UV-B radiation, we analysed the differential response of 5 poplar genotypes selected along a latitudinal and altitudinal gradient. Three years old rooted plants were acclimated in two identical phytotrons, except the presence of aUVBlamp array in just one of them. Inorder to simulate an environmental condition, plants were treated for 16 hours with an UVBbe (UVB biologically effective radiation) supplementary dose of 6 KJ/m2/day and allowed to recover during the night (8 hours). After plants were first adapted for 30 min in total darkness, chlorophyll fluorescence of PSII was measured. The ecophysiological data showed a decrease of the maximum efficiency of the PSII in the stressed plants, in particular for 3 clones, during the hours of the UVB treatment. We studied also, the association between polymorphism data (SNP) and expression level on genes (such as chs, comt, rbcl, and photolyase) putatively related to UV-B response. The leaf tissue of the 5 genotypes were sampled after treatment for 3, 6, 12 and 36 hours with UVB, and were analyzed using qRTPCR. Chs gene show high expression levels after 12 (3 genotypes) and 36 hours (1 genotype) of treatment, while comt gene show high levels of expression after 12 hours (4 genotypes) of treatment. Instead, photolyase gene show high levels of transcription just after 3 hours (1 genotype) of treatment and later his expression levels decreases. The qRT-PCR data show that there is not a significant difference of expression patterns for rbcL among the genotypes with a decrease that is consistent with the eco-physiological results. The results showed a different pattern of expression, with a dissimilar response among the clones analyzed towards the stress. Must still be clarified the association between the ecophysiological and expression data, with the sequences polymorphism analysis because of the absence of missense mutations.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
