Project description:Tocopherols (vitamin E) are lipid-soluble antioxidants produced by all plants and algae, and many cyanobacteria, yet their functions in these photosynthetic organisms are still not fully understood. We have previously reported that the vitamin E deficient 2 (vte2) mutant of Arabidopsis thaliana is sensitive to low temperature (LT) due to impaired transfer cell wall (TCW) development and photoassimilate export, associated with massive callose deposition in transfer cells of the phloem. To further understand the roles of tocopherols in LT induced TCW development we compared the global transcript profiles of vte2 and wild type leaves during LT treatment. Tocopherol deficiency had no significant impact on global gene expression in permissive conditions, but significantly affected expression of 77 genes after 48 hours of LT treatment. In vte2 relative to wild type, genes associated with solute transport were repressed, while those involved in various pathogen responses and cell wall modifications, such as GLUCAN SYNTHASE LIKE genes (GSL4 and GSL11), were induced.
Project description:We collected tissues from bent cotyledon stage zygotic embryos, proliferating tissue at day 7 and day 14 induction of somatic embryogenesis and mature somatic emrbyos in a wild type (Col-0) and vtc2 (SALK_146824) insertion. We used microarrays to identify global patterns of gene activity during somatic embryogenesis in a wild type (Col-0) and vitamin C deficient mutant (vtc2)
Project description:We collected tissues from bent cotyledon stage zygotic embryos, proliferating tissue at day 7 and day 14 induction of somatic embryogenesis and mature somatic emrbyos in a wild type (Col-0) and vtc2 (SALK_146824) insertion. We used microarrays to identify global patterns of gene activity during somatic embryogenesis in a wild type (Col-0) and vitamin C deficient mutant (vtc2) RNA was extracted and amplified from four stages of somatic embryogenesis (bent cotyledon, day 7 induction, day 14 induction, and mature somatic embryos) in a wild type (Col-0) and vitamin C deficient mutant (vtc2) before being hybridized to the Arabidopsis ATH1 GeneChip in duplicate (two biological replicates).
Project description:Keeping imbibed seeds at low temperatures for a certain period, so called seed vernalization (SV) treatment, promotes seed germination and subsequent flowering in various plants. Vernalization-promoting flowering requires GSH. However, the expression patterns analyzed by GeneChip arrays showed that increased GSH biosynthesis partially mimics SV treatment in Arabidopsis thaliana. SV treatment (keeping imbibed seeds at 4°C for 24 h) induced a specific pattern of gene expression and promoted subsequent flowering in wild-type plants. A similar pattern was observed at 22°C in transgenic plants (35S-GSH1 plants) overexpressing the γ-glutamylcysteine synthetase gene GSH1, coding an enzyme limiting GSH biosynthesis, under the control of the cauliflower mosaic virus 35S promoter. This pattern was strengthened at 4°C but flowering was less responsive to SV treatment. There was a difference in the transcript behaviour of the flowering repressor FLC between wild-type and 35S-GSH1 plants. Unlike other genes responsive to SV treatment, SV-dependent decrease in FLC in wild-type plants was reversed in 35S-GSH1 plants. SV treatment increased GSSG level in wild-type seeds, whereas GSSG level was high in 35S-GSH1 plants, even at a non-vernalizing temperature. Taking into consideration that low temperatures stimulate GSH biosynthesis and bring about oxidative stress, GSSG is considered to trigger low temperature response, but enhanced GSH synthesis was not enough for mimicking SV treatment. To complete it, it essentially required the cellular redox retransition from the oxidized to the reduced state that is observed after the seed vernalization treatment.
Project description:Tocopherols (Vitamin E) are lipophilic antioxidants that are synthesized by all plants and are particularly abundant in seeds. Two tocopherol deficient mutant loci were used to examine how tocopherol deficiency impacts global gene expression during the critical peroid of germination and early seedling development when tocopherols are essential. vte1 lacks all tocopherols, but accumulates the tocopherol pathway intermediate DMPBQ,. vte2 which lacks all tocopherols and pathway intermediates. We used microarrays to examine the global gene expression in early seedlings and identify distinct classes of genes whose expression is affected by tocopherol deficient mutants vte1 and vte2. Experiment Overall Design: Arabidopsis seedlings were grown on media containing MS salts at 22C and RNA was extracted from 1 (1D)and 3 (3D)day old seedlings following cold treatment to break dormancy and synchronize germination (5 days at 6C) . We sought to compare the two tocopherol deficient mutants vte1 (VTE1) and vte2 (VTE2) with each other and the corresponding wild-type background Columbia-0 (COL).
Project description:We performed a microarray experiment to assess the global changes in transcription occurring in leaves and roots of the vitamin B6 deficient pdx1.3 knockout mutant in comparison to WT. Vitamin B6 (pyridoxal 5′-phosphate) is an essential cofactor of many metabolic enzymes. Plants biosynthesize the vitamin de novo employing two enzymes, pyridoxine synthase1 (PDX1) and PDX2. In Arabidopsis (Arabidopsis thaliana), there are two catalytically active paralogs of PDX1 (PDX1.1 and PDX1.3) producing the vitamin at comparable rates. Since single mutants are viable but the pdx1.1 pdx1.3 double mutant is lethal, the corresponding enzymes seem redundant. However, the single mutants exhibit substantial phenotypic differences, particularly at the level of root development, with pdx1.3 being more impaired than pdx1.1. Here, we investigate the impact of possible global changes in gene expression in the pdx1.3 mutant compared to WT on the phenotype.