Project description:To better understand the regulatory mechanisms of water stress response in wheat, the transcript profiles in roots of two wheat genotypes, namely, drought tolerant 'Luohan No.2' (LH) and drought susceptible 'Chinese Spring' (CS) under water-stress were comparatively analyzed by using the Affymetrix wheat GeneChip®. A total of 3831 transcripts displayed 2-fold or more expression changes, 1593 transcripts were induced compared with 2238 transcripts were repressed, in LH under water-stress; Relatively fewer transcripts were drought responsive in CS, 1404 transcripts were induced and 1493 were repressed. Comparatively, 569 transcripts were commonly induced and 424 transcripts commonly repressed in LH and CS under water-stress. 689 transcripts (757 probe sets) identified from LH and 537 transcripts (575 probe sets) from CS were annotated and classified into 10 functional categories, and 74 transcripts derived from 80 probe sets displayed the change ratios no less than 16 in LH or CS. Several kinds of candidate genes were differentially expressed between the LH and CS, which could be responsible for the difference in drought tolerance of the two genotypes.
Project description:To better undersand the effects of drought stress on wheat developing seeds, the transcription profile of early developing wheat seeds under control and drought stress conditions were comparatively analyzed by using the Affymetrix wheat geneChip. Drought stress is a major yield-limiting factor for wheat. Wheat yields are particularly sensitive to drought stress during reproductive development. Early seed development stage is an important determinant of seed size, one of the yield components. We specifically examined the impact of drought stress imposed during postzygotic early seed development in wheat. We imposed a short-term drought stress on plants with day-old seeds and observed that even a short-duration drought stress significantly reduced the size of developing seeds as well as mature seeds. Drought stress delayed the developmental transition from syncytial to cellularized stage of endosperm. Coincident with reduced seed size and delayed endosperm development, a subset of genes associated with cytoskeleton organization was misregulated in developing seeds under drought-stressed. Several genes linked to hormone pathways were also differentially regulated in response to drought stress in early seeds. Notably, drought stress strongly repressed the expression of wheat storage protein genes such as gliadins, glutenins and avenins as early as 3 days after pollination. Our results provide new insights on how some of the early seed developmental events are impacted by water stress, and the underlying molecular pathways that can possibly impact both grain size and quality in wheat.
Project description:To better understand the regulatory mechanisms of water stress response in wheat, the transcript profiles in roots of two wheat genotypes, namely, drought tolerant 'Luohan No.2' (LH) and drought susceptible 'Chinese Spring' (CS) under water-stress were comparatively analyzed by using the Affymetrix wheat GeneChip®. A total of 3831 transcripts displayed 2-fold or more expression changes, 1593 transcripts were induced compared with 2238 transcripts were repressed, in LH under water-stress; Relatively fewer transcripts were drought responsive in CS, 1404 transcripts were induced and 1493 were repressed. Comparatively, 569 transcripts were commonly induced and 424 transcripts commonly repressed in LH and CS under water-stress. 689 transcripts (757 probe sets) identified from LH and 537 transcripts (575 probe sets) from CS were annotated and classified into 10 functional categories, and 74 transcripts derived from 80 probe sets displayed the change ratios no less than 16 in LH or CS. Several kinds of candidate genes were differentially expressed between the LH and CS, which could be responsible for the difference in drought tolerance of the two genotypes. Two common wheat (Triticum aestivum L.) cultivars, Luohan No.2 (LH) and Chinese Spring (CS), were used for this study. Seedlings at the two leaf stage were stressed by cultured in PEG solutions for 6h, and some other seedlings were cultured in tap water as control. Root samples of LH and CS at 6h after the stress treatment and untreated control were prepared for microarray analysis.
Project description:To better undersand the effects of drought stress on wheat developing seeds, the transcription profile of early developing wheat seeds under control and drought stress conditions were comparatively analyzed by using the Affymetrix wheat geneChip. Drought stress is a major yield-limiting factor for wheat. Wheat yields are particularly sensitive to drought stress during reproductive development. Early seed development stage is an important determinant of seed size, one of the yield components. We specifically examined the impact of drought stress imposed during postzygotic early seed development in wheat. We imposed a short-term drought stress on plants with day-old seeds and observed that even a short-duration drought stress significantly reduced the size of developing seeds as well as mature seeds. Drought stress delayed the developmental transition from syncytial to cellularized stage of endosperm. Coincident with reduced seed size and delayed endosperm development, a subset of genes associated with cytoskeleton organization was misregulated in developing seeds under drought-stressed. Several genes linked to hormone pathways were also differentially regulated in response to drought stress in early seeds. Notably, drought stress strongly repressed the expression of wheat storage protein genes such as gliadins, glutenins and avenins as early as 3 days after pollination. Our results provide new insights on how some of the early seed developmental events are impacted by water stress, and the underlying molecular pathways that can possibly impact both grain size and quality in wheat. Winter wheat cultivar Redland, PI 502907 (Triticum aestivum L.) was used for this study. Seedlings were vernalized at 4°C for 6 weeks and then transplanted to a one gallon pot of soil-sand mixture (3:1, v/v) and grown in a growth chamber under the following conditions: relative humidity, 50–70%; 16-h light/8-h dark photoperiod; 21°C daytime temperature and 18°C nights. Plants were watered regularly twice daily at the rate of 100ml/ per pot. Because, wheat has an asynchronous fertilization pattern for ovlues in the inflorescence, each floret needs to be specifically marked for timing the fertilization and stress induction. After spikes developed, unfertilized ovules were monitored and observed for the fertilization process. Closed wheat spikes with anthers outside were marked as fertilized. Drought stress was imposed 24h after the fertilization (HAF). Drought stress treatment was initiated by discontinuing watering on the drought treatment plants while control plants were regularly watered twice daily. Stress treatment was applied at 48 HAF and relieved at 96 HAF. The microarray study focuses on 24 HAF to 72 HAF in control and drought stress conditions. We started to impose drought stress 24HAF.
Project description:Based on EST-based in silico gene expression analysis a 15k oligonucleotid microarray has been developped in order to monitor environmental stress-dependent gene expression changes in the wheat caryopsis. Using this array, the effect of water withdrawal, with and and without additional heat stress, during the first five days of grain development (0-5 DAA) has been investigated on two wheat cultivars differing in their drought sensitivity. The combined effect of heat and drought (DH) on gene expression was much significant (8-10% of the investigated genes changed >2-fold) in contrast to drought alone (1.5%). Drought and heat stress resulted in the co-ordinated change of the expression of storage proteins, some enzymes involved in sugar/starch metabolism, cell division-related and histone proteins, certain transcription factors, heat shock proteins, proteases and aquaporins. The potential link between the observed gene expression changes and the parallel histological observations indicating the accelerated development of the stressed grains is discussed.
Project description:Based on EST-based in silico gene expression analysis a 15k oligonucleotid microarray has been developped in order to monitor environmental stress-dependent gene expression changes in the wheat caryopsis. Using this array, the effect of water withdrawal, with and and without additional heat stress, during the first five days of grain development (0-5 DAA) has been investigated on two wheat cultivars differing in their drought sensitivity. The combined effect of heat and drought (DH) on gene expression was much significant (8-10% of the investigated genes changed >2-fold) in contrast to drought alone (1.5%). Drought and heat stress resulted in the co-ordinated change of the expression of storage proteins, some enzymes involved in sugar/starch metabolism, cell division-related and histone proteins, certain transcription factors, heat shock proteins, proteases and aquaporins. The potential link between the observed gene expression changes and the parallel histological observations indicating the accelerated development of the stressed grains is discussed. 8 samples with 2 biological replicate using dye swap
Project description:Purpose: To identify abiotic stress responsive and tissue specific miRNAs at genome wide level in wheat (Triticum aestivum) Results: Small RNA libraries were constructed from four tissues (root, shoot, mature leaf and spikelets) and three stress treatments of wheat seedlings (control, high temperature, salinity and water-deficit). A total of 59.5 million reads were obtained by high throughput sequencing of eight wheat libraries, of which 32.5 million reads were found to be unique. Using UEA sRNA workbench we identified 47 conserved miRNAs belonging to 20 families, 1030 candidate novel and 51 true novel miRNAs. Several of these miRNAs displayed tissue specific expression whereas few were found to be responsive to abiotic stress treatments. Target genes were predicted for miRNAs identified in this study and their grouping into functional categories revealed that the putative targets were involved in diverse biological processes. RLM-RACE of predicted targets of three conserved miRNAs (miR156, miR160 and miR164) confirmed their mRNA cleavage, thus indicating their regulation at post-transcriptional level by corresponding miRNAs. Expression profiling of confirmed target genes of these miRNAs was also performed. Conclusions: This is the first comprehensive study on profiling of miRNAs in a variety of tissues and in response to several abiotic stresses in wheat. Our findings provide valuable resource for better understanding on the role of miRNAs in stress tolerance as well as plant development. Additionally, this information could be utilized for designing wheat plants for enhanced abiotic stress tolerance and higher productivity. Total eight (three stress, one control and four tissue specific small RNA libraries were pepared and sequenced independently [wheat control (WC), wheat high temperature stressed (WHTS), wheat salinity stressed (WSS) and wheat drought stressed (WDS), wheat shoot(WSH), wheat leaf (WLF), wheat flower(WFL), wheat root(WRT)] on Illumina GAIIx
Project description:The study was conducted in order to find out the differential change in the transcript of tolerant and susceptible wheat cultivar under heat stress and to decipher the mechanism of thermotolerance in wheat by identifying novel genes and transcription factors involved in the pathways. Wheat cultivar HD2985 (thermotolerant) and HD2329 (thermosusceptible) were exposed to heat stress of 42 degree for 4h at pollination stage and samples were collected from both control and heat shock treated plants for further characterization.