Project description:Global expression analysis of transcripts in response to salt treatment was carried out for common wheat using oligo-DNA microarrays. Microarrays have been designed from unique wheat genes classified from a large number of expressed sequence tags (ESTs). Two-week-old seedlings of common wheat were treated with 150 mM NaCl for 1, 6 and 24 hours and their roots and shoots were separately subjected to microarray analyses. Consequently, 5996 genes showed changes in expression of more than two-fold, and were classified into 12 groups according to correlations in gene expression patterns. These salt-responsive genes were assigned functions using Gene Ontology (GO) terms. Genes assigned to transcription factor, transcription-regulator activity and DNA binding functions were preferentially classified into early response groups. On the other hand, those assigned transferase and transporter activity were classified into late response groups. These data on gene expression suggest that multiple signal transduction pathways in response to salt treatment exist in wheat. Salt-responsive transcription factors (TFs), namely AP2/EREBP, MYB, NAC and WRKY, were selected and their expression patterns compared with those of rice. Most showed different expression patterns in wheat and rice in response to salt treatment. Furthermore, comparing the microarray data for wheat and rice, only a small number of genes were up- or down-regulated in common in response to salt treatment. These findings suggest that salt-responsive mechanisms distinct from rice might be present in wheat, and wheat genes can contribute to providing novel gene resources for breeding of salt-tolerant crops. Keywords: time cource, stress response
Project description:The supply of soluble silicon (Si) to plants has been associated with many benefits that remain poorly explained and often contested. In this work, the effect of Si was studied on wheat plants under both control and pathogen stress (Blumeria graminis f.sp. tritici (Bgt)) conditions by conducting an exhaustive transcriptomic analysis (55,000 genes) aimed at comparing the differential response of plants under four treatments. The response to the supply of Si on control (uninfected) plants was limited to 47 genes providing little evidence of regulation of a specific metabolic process. Plants reacted to inoculation with Bgt by an up-regulation of many genes linked to stress and metabolic processes and a down-regulation of genes linked to photosynthesis. Supplying Si to inoculated plants largely prevented disease development, a phenotypic response that translated into a nearly perfect reversal of genes regulated by the effect of Bgt alone. These results suggest that Si plays a limited role on a plant’s metabolism in absence of stress, even in the case of a high-Si accumulating monocot such as wheat. On the other hand, the benefits of Si, in the form of biotic stress alleviation, were remarkably aligned with a counter-response to transcriptomic changes induced by the pathogen Bgt. Keywords: stress type and molecule effect
Project description:Silicon (Si) has long been known to play a major physiological role in certain organisms, including some sponges and many diatoms and higher plants, leading to the recent identification of multiple proteins responsible for silicon transport in a range of algal and plant species. In mammals, despite several convincing studies suggesting that silicon is an important factor in bone development and connective tissue health, there is a critical lack of understanding in biochemical pathways that enable silicon homeostasis. Here we report the identification of a mammalian efflux silicon transporter, namely Slc34a2 (also known as NaPiIIb), which was upregulated in the kidneys of rats following chronic dietary silicon deprivation. When heterologously expressed in Xenopus laevis oocytes, the protein displayed marked silicon transport activity, specifically efflux, comparable to plant OsLsi2 transfected in the same fashion and independent of sodium and/or phosphate influx. This is the first evidence for a specific active transporter protein for silicon in mammals and suggests an important role for silicon in vertebrates.
Project description:Global expression analysis of transcripts in response to salt treatment was carried out for common wheat using oligo-DNA microarrays. Microarrays have been designed from unique wheat genes classified from a large number of expressed sequence tags (ESTs). Two-week-old seedlings of common wheat were treated with 150 mM NaCl for 1, 6 and 24 hours and their roots and shoots were separately subjected to microarray analyses. Consequently, 5996 genes showed changes in expression of more than two-fold, and were classified into 12 groups according to correlations in gene expression patterns. These salt-responsive genes were assigned functions using Gene Ontology (GO) terms. Genes assigned to transcription factor, transcription-regulator activity and DNA binding functions were preferentially classified into early response groups. On the other hand, those assigned transferase and transporter activity were classified into late response groups. These data on gene expression suggest that multiple signal transduction pathways in response to salt treatment exist in wheat. Salt-responsive transcription factors (TFs), namely AP2/EREBP, MYB, NAC and WRKY, were selected and their expression patterns compared with those of rice. Most showed different expression patterns in wheat and rice in response to salt treatment. Furthermore, comparing the microarray data for wheat and rice, only a small number of genes were up- or down-regulated in common in response to salt treatment. These findings suggest that salt-responsive mechanisms distinct from rice might be present in wheat, and wheat genes can contribute to providing novel gene resources for breeding of salt-tolerant crops. Microarray hybridization was performed by a competitive two-color method including color-swap experiments. Chinese Spring wheat was grown for two weeks and treated with 150mM NaCl for 0, 1, 6 and 24 hours. RNA samples were extracted from roots and shoots.