Project description:A heat and drought tolerant rice cultivar (N22) was grown in the field under control and drought conditions during the dry season in 2013. Drought was applied during early grain filling and resulted in simultaneous heat stress, leading to reduced grain yield and quality. Total RNA was extracted from developing seeds under stress and control (fully flooded) conditions and RNA-seq analysis was performed. These samples are a part of a bigger experiment analysing the responses of three contrasting rice cultivars (N22, Dular, Anjali) to combined heat and drought stress including different organs (developing seeds, flag leaves, flowering spikelets) and developmental stages (early grain filling, flowering) at the transcriptomic level.
Project description:Rice is susceptible to both heat and drought stress, in particular during flowering and grain filling, when both grain yield and quality may be severely compromised. However, under field conditions, these two stresses rarely occur separately. Under well-watered conditions, plants avoid heat stress by transpirational cooling, while this is not possible under drought conditions. Although investigating combined heat and drought stress is clearly more agronomically relevant than analyzing the effects of the single stresses, only a few studies of this stress combination, in particular under field conditions, have been published. Furthermore, little is known about how plants respond during recovery from drought stress, which also determines plant survival. To address these knowledge gaps, three rice cultivars differing in heat and drought tolerance were grown in the field under control and drought conditions in three consecutive years. Drought was applied either during flowering or during early grain filling, resulting in simultaneous heat stress, leading to reduced grain yield and quality. Analysis by gas chromatography-mass spectrometry (GC-MS) showed distinct metabolic profiles for the three investigated organs (flag leaves, flowering spikelets, developing seeds). The metabolic responses of the plants also strongly differed between cultivars and organs, and between stress and rewatering conditions. Correlation analysis identified potential metabolic markers for grain yield and quality under combined heat and drought stress from stress- and rewatering-regulated metabolites and from metabolites with constitutive differences between the cultivars. These results show that GC-MS can resolve metabolic responses to combined heat and drought stress and subsequent rewatering in different organs of field-grown rice. The metabolite profiles can be used to identify potential marker metabolites for yield stability and grain quality that are expected to improve breeding efforts towards climate change resilient rice.
Project description:Floral organs are extremely sensitive to stress during anthesis and lead to severe yield loss. Rice anthers and pollinated pistils of two cultivars with contrasting tolerance to heat and drought stress under variable conditions, including control, heat, combined heat and drought stress, were used to explore gene expression pattern in male and female reproductive organs during anthesis under control and stress conditions. More gene regulation was induced by combined drought and heat stress than heat in anthers of both cultivars. N22 showed less regulation under combined stress than Moroberekan. The overlap of regulated genes between two cultivars was rather low, indicated the distinct molecular stress responses. We used whole genome microarrays to explore gene expression pattern and molecular mechanisms in male and female reproductive organs during anthesis under control and stress conditions in two rice cultivars, sought to identify the key transcripts that play roles in inducing heat and drought tolerance during reproduction in rice.
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:Sorghum is an important crop often subjected to simultaneous high temperatures and drought in the field. We examined the gene expression response to heat and drought stress both individually, and in combination, with the aim of identifying important stress tolerance mechanisms. Plants were subjected to 4 different conditions (control, heat shock, drought stress and combined heat and drought stress). 3 replicates were carried out for each treatment type giving a total of 12 samples
Project description:One of the eminent opportunities afforded by modern genomic technologies is the potential to provide a mechanistic understanding of the processes by which genetic change translates to phenotypic variation and the resultant appearance of distinct physiological traits. Indeed much progress has been made in this area, particularly in biomedicine where functional genomic information can be used to determine the physiological state (e.g., diagnosis) and predict phenotypic outcome (e.g., patient survival). Until now, ecology has lacked an analogous approach where genomic information can be used to diagnose the presence of a given physiological state (e.g., stress response) and then predict likely phenotypic outcomes (e.g., stress tolerance, fitness). We demonstrate that a compendium of genomic signatures can be used to classify the plant abiotic stress phenotype in Arabidopsis according to the architecture of the transcriptome, and then be linked with gene coexpression network analysis to determine the underlying signaling pathways and ultimately the genes governing the phenotypic response. Here, we release microarray data from an expression profiling study where plants were exposed to heat and drought alone, and in combination with each other. A direct loop design with 6 biological replicates for control, heat, drought, and combined heat and drought was performed. A schematic describing the design is provide as supplementary information.
Project description:One of the eminent opportunities afforded by modern genomic technologies is the potential to provide a mechanistic understanding of the processes by which genetic change translates to phenotypic variation and the resultant appearance of distinct physiological traits. Indeed much progress has been made in this area, particularly in biomedicine where functional genomic information can be used to determine the physiological state (e.g., diagnosis) and predict phenotypic outcome (e.g., patient survival). Until now, ecology has lacked an analogous approach where genomic information can be used to diagnose the presence of a given physiological state (e.g., stress response) and then predict likely phenotypic outcomes (e.g., stress tolerance, fitness). We demonstrate that a compendium of genomic signatures can be used to classify the plant abiotic stress phenotype in Arabidopsis according to the architecture of the transcriptome, and then be linked with gene coexpression network analysis to determine the underlying signaling pathways and ultimately the genes governing the phenotypic response. Here, we release microarray data from an expression profiling study where plants were exposed to heat and drought alone, and in combination with each other. Keywords: Stress response, heat, drought, combined stress
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:Plants of a “Hana-type” landrace (B1) were taller, flowered earlier and produced heavier, larger and more vigorous seeds that resisted ageing longer compared to a semi-dwarf breeding line (B2). Drought significantly reduced seed yield in both genotypes, and elevated temperature reduced seed size. Genotype B2 showed partial thermodormancy that was alleviated by drought and elevated temperature, in line with lower abundance of the TF ABI5, a key regulator of seed dormancy and vigour. Metabolite profiling revealed clear differences between the embryos of B1 and B2. Drought, but not elevated temperature, affected the metabolism of amino acids, organic acids, osmolytes and nitrogen assimilation, in the seeds of both genotypes.
Project description:Durum wheat is an important cereal crop grown mainly in semi-arid environments (e.g. Mediterranean regions) characterized by water scarcity and high temperatures often occurring at the same time. This work reports on a transcriptomic analysis carried out on two durum wheat cultivars (Cappelli and Ofanto) characterized by different water use efficiency (WUE), grown to booting stage and subjected to a combination of drought and heat stresses, a situation similar to the experience of a crop grown in Mediterranean environments and exposed to a terminal heat/drought stress. ****[PLEXdb(http://www.plexdb.org) has submitted this series at GEO on behalf of the original contributor, alessio. The equivalent experiment is TA47 at PLEXdb.]