Transcription profiling by array of Saccharin latissima sporophytes following exposure to combinations of radiation at 3 different temperatures
ABSTRACT: Sporophytes of Saccharina latissima were exposed for two weeks to 12 different combinations of photosynthetically active radiation and UVR at three different temperatures (2,7,12 C). Maximum quantum yield of photosystem II was determined twice a week during the experimental duration for observing the extent of photoinhibition. For investigating molecular mechanisms of acclimation to high photosynthetically radiation, and UVR gene expression profiles were assessed through microarray hybridizations.
Project description:To explore possible interactive effects of UV-radiation, temperature and growth conditions, cultivated and field sporophytes of Saccharina latissima were exposed for 24h to UV-radiation at three different temperatures (2,7 & 12°C). Gene expression profiles under UV-radiation at different temperatures were assessed through microarray hybridizations, afterwards comparisons of gene expression profiles in field and culture sporophytes were carried out.
Project description:Effect of PAR and temperature stress on the gene expression Saccharina latissima. Total RNA of stress treatments (low PAR 2° and 17°C, high PAR 2° and 17°C) was hybridized against the control treatment (low PAR 12°C); hybridizations were carried out in 4 replicates.
Project description:In the present study we have used a new custom made Affymetrix GrapeGen GeneChip to investigate gene expression responses of grapevine cultivar Malbec to one dose of biologically effective UV-B radiation (4.75 kJ m-2 d-1), administered at two different intensities (16 h, to 8.25 µW cm-2 or 4 h, to 33 µW cm2 UV-B).
Project description:Recently, we found a dioecious plant Populus cathayana males possess a greater tolerance to enhanced UV-B radiation than do females. To carry this work forward, comparative transcriptome analyses were carried out. Similar to previous studies, a set of conserved functions and pathways related to UV-B stress were detected in males and females, regardless of the sex. In addition, sex-specific responses via transcriptome remodeling were also detected as shown in the changes of sex-related gene expression occurred in some pathways. For example, a lot of differentially expressed genes (DEGs) involved in amino acid metabolism were mainly up-regulated in males, but down-regulated in females. Moreover, we found some DEGs expressed predominantly or exclusively in one sex, which may directly contribute to sex-related physiological responses. 4 samples examined: (i) males exposure to decreased solar UV-B radiation (MC); (ii) females exposure to decreased solar UV-B radiation (FC); (iii) males exposure to ambient solar UV-B radiation (MU); and (iv) females exposure to ambient solar UV-B radiation (FU). Nine plants of each sex were exposed to each treatment, and RNA samples from the 9 individuals were pooled with equal proportion.
Project description:In dense plant stands, the ratio between red and far-red (R:FR) light declines and shade intolerant species will respond to this cue for future shade by inducing the shade avoidance syndrome (SAS), enabling them to outgrow their neighbours. Shade tolerant species from the forest understory are unable to outgrow neighbouring trees and will suppress SAS. Although the molecular mechanisms underlying SAS are well studied in various species, mechanisms of SAS-suppression in shade tolerant species have rarely been studied. We applied RNA sequencing on Geranium pyrenaicum and G. robertianum, two wild species with contrasting growth responses to low R:FR light. G. pyrenaicum strongly induces petiole elongation when exposed to low R:FR light, at any time of the photoperiod. Contrastingly, G. robertianum only induces this response early in the day, and suppresses petiole growth in low R:FR light at the end of the photoperiod, which results after 24 hours in a net difference with control treatments of zero. We compared expression patterns in the most apical (most responsive) part of the second petioles, in two-week-old Geranium plants (two leaf stage) after 2 and 11.5 hours of far-red light enrichment. This way, we identified a number of novel candidate regulators of shade avoidance, and differential phytochrome control of plant immunity genes in the two species. For de-novo assembly of the reference transcriptomes, we pooled petiole- and leaf lamina tissue exposed to normal white light (180 mol m-2 s-1 PAR, R:FR 1.8, ± 60 mol m-2 s-1 blue light), low R:FR light (0.2), blue-depleted light (± 4 mol m-2 s-1 blue) and green shade (50 mol m-2 s-1 PAR, R:FR 0.45, ± 13 mol m-2 s-1 blue) for 2, 11.5 and 24 hours. Libraries of these samples were normalized, Illumina sequenced, and together with sequences of non-normalized petiole samples of the expression analysis constructed into a reference transcriptome for each species, using the Trinity protocol. Transcripts were clustered into orthologue clusters using the ortho-MCL clustering technique. Non-normalized libraries of samples (control vs. low R:FR light, 2 and 11.5 hours after start of the treatment) were sequenced and aligned to the newly assembled transcriptomes. Read counts were summed per orthologue cluster before statistical analysis was proceeded.
Project description:To identify components involved in the signal transduction and activation of the singlet oxygen-mediated response, a mutant selection was performed. This led to the isolation of the singlet oxygen resistant 1 (sor1) mutant, which is more tolerant to singlet oxygen-producing chemicals and shows a constitutively higher expression of GPXH and GSTS1. Map-based cloning revealed that the SOR1 gene encodes a novel bZIP transcription factor, which seems to control its own expression as well as that of a large number of oxidative stress response and detoxification genes. In the promoter region of many of these genes a highly conserved 8-bp palindromic sequence element was found to be enriched. This element was shown to be essential for GSTS1 overexpression in sor1 and for induction by increased levels of lipophilic reactive electrophile species (RES) suggesting that it functions as an electrophile response element (ERE). RES can be formed after singlet oxygen-induced lipid peroxidation, indicating that a RES-stimulated and SOR1-mediated response of detoxification genes is part of the singlet oxygen-induced acclimation process in C. reinhardtii. The sor1 mutant isolated in a screen for singlet oxygen resistant mutants and the corresponding wild-type strain 4A+ were grown in a 12 h light dark cycle for several days before total RNA was extracted 6 h after the light came on.
Project description:Urocanic acid (UCA) is a major epidermal chromophore that undergoes trans to cis photoisomerisation following exposure to solar ultraviolet radiation (UVR). Although there is considerable evidence that cis-UCA suppresses cell-mediated immune response in mouse skin, the molecular events are not fully understood. In this study, we examined involvement of gene transcription in the immunomodulatory effects of cis-UCA on primary human keratinocytes. The results showed that about 400 genes were induced by UVR, 16 of which also up-regulated by cis-UCA. In contrast, trans-UCA had no effect on gene expression. The genes up-regulated by both cis-UCA and UVR were associated with apoptosis, cell growth arrest, cytokines and oxidative stress. Experiment Overall Design: RNA was extracted from primary human keratinocytes treated with trans-, cis-UCA (10ug/ml) or solar simulated UVR (12J/cm2 ~ 2-3 minimal erythema doses for fair skin), or untreated. At 24hr, the transcriptional profiles were assessed by Affymetrix HG-U133A microarray.