Project description:This was a comparative transcriptome analysis by using high throughput sequencing. To assess the effects of drought stress and NF-Y transcription factors ZmNF-YA1 and ZmNF-YB16 on maize, leaves from wild-type (W22), zmnf-ya1 (m67) mutant, wild-type (B104) and ZmNF-YB16 overexpression (OE) plants grow under well-watered and drought stress conditions were collected and RNAseq was performed. We tracked the gene expression events of inbred maize lines W22 or B104 seedlings in response to drought stress to evaluate how drought stress affects the gene expression program in maize. At the same time, we analyzed the effects of drought stress on gene expression in zmnf-ya1 and ZmNF-YB16 OE plants to investigate whether and how ZmNF-YA1 and ZmNF-YB16 confer drought stress tolerance in maize. Maize plants were grown under well-watered conditions until the V4 stage (zmnf-ya1 and W22) or V9 stage (ZmNF-YB16 OE and B104), and then half of them were exposed to drought stress treatment. Water loss in the soil and the electrolyte leakage from leaf cells were used to assess drought stress in plants. Leaves from 3-4 plants were pooled for each sample, and two replicates were used. RNA was extracted from small strips of leaf lamina excised from the first fully expanded leaf of the plants.
2019-09-21 | GSE137780 | GEO
Project description:High temperature drought stress
Project description:In this work, we performed high throughput sequencing of small RNA libraries in maize (Zea mays ssp. mays) and teosinte (Zea mays ssp. parviglumis) to investigate the response mediated by miRNAs in these plants under control conditions, submergence, drought and alternated drought-submergence or submergence-drought stress. After Illumina sequencing of 8 small RNA libraries, we obtained from 16,139,354 to 46,522,229 raw reads across the libraries. Bioinformatic analysis identified 88 maize miRNAs and 76 miRNAs from other plants differentially expressed in maize and/or in teosinte in response to at least one of the treatments, and revealed that a larger set of miRNAs were regulated in maize than in teosinte in response to submergence and drought stress.
Project description:Plant reproduction is one key biological process very sensitive to heat stress and, as a consequence, enhanced global warming imposes serious threats to sustain food safety worldwide. In this work we have focused on the molecular impact that high temperature conditions impose on gene expression of Arabidopsis pollen germinated in vitro. We have used a high-resolution ribosome profiling technology to provide, for the first time, a comprehensive study of how both the transcriptome and the translatome of germinated pollen respond to the increase in temperature. Although heat shock responses operate properly under high temperature conditions, we have uncovered important alterations under elevated temperature regimes down-regulating essential processes linked to cation/proton exchange and to carbohydrate/cation symport transport. These alterations provide molecular explanations to the dramatic alterations of pollen tube growth under heat stress. Overall a high correlation between transcriptional and translational responses to high temperature was found, but specific regulations at the translational level are also present in pollen subjected to temperature challenging conditions.
Project description:Purpose: Brassica. juncea is vulnerable to abiotic stresses at specific stages in its life cycle. However, till date no attempts have been made to elucidate the genome-wide changes in the transcriptome of B. juncea subjected to either high temperature or drought stress. Hence, to gain global insights into genes, transcription factors and kinases regulated by these stresses and to provide basic information on coding transcripts that are associated with traits of agronomic importance, we utilized a combinatorial approach of next generation sequencing and de novo assembly to discover B. juncea transcriptome associated with high temperature and drought. Results: We constructed and sequenced three transcriptome libraries namely Brassica control (BC), Brassica high temperature stress (BHS) and Brassica drought stress (BDS) from control, high temperature treated and drought treated seedlings of Brassica juncea. More than 180 million purity filtered reads were generated which were processed through quality parameters and high quality reads were assembled de-novo using SOAPde-novo assembler. A total of 77750 unique transcripts were identified out of which 69,245 (89%) were annotated with high confidence. We established a subset of 19110 transcripts, which were differentially regulated by either high temperature and/or drought stress. Furthermore, 886 and 2834 transcripts that code for transcription factors and kinases, respectively, were also identified. Investigation of identified transcription factors revealed that 92 responded to high temperature, 72 exhibited alterations in expression during drought stress, and 60 were commonly associated with both the stresses. Similarly, 217, 259 and 193 kinases were responsive to high temperature, drought or both stresses, respectively. Maximum number of up-regulated transcription factors in high temperature and drought stress belonged to heat shock factors (HSFs) and dehydration responsive element-binding (DREB) families respectively. We also identified 239 metabolic pathways, which were perturbed during high temperature and drought treatments. Analysis of gene ontologies associated with differentially regulated genes forecasted their involvement in diverse biological processes. Conclusions: Our study provides first comprehensive discovery of B. juncea transcriptome under high temperature and drought stress conditions. Transcriptome resources generated in this study will enhance our understanding on the molecular mechanisms involved in defining the response of B. juncea against two important abiotic stresses. Furthermore this information would benefit designing of efficient crop improvement strategies for tolerance against conditions of high temperature regimes and water scarcity.
Project description:Drought is a major abiotic stress that threatens global food security. Circular RNAs (circRNAs) are endogenous RNAs. How these molecules influence plant stress responses remains elusive. Here, a large scale circRNA profiling identified 2174 and 1354 high-confidence circRNAs in maize and Arabidopsis, respectively, and most were differentially expressed in response to drought. A substantial number of drought-associated circRNA hosting genes were involved in conserved or species-specific pathways in drought responses. Comparative analysis revealed that circRNA biogenesis was more complex in maize than in Arabidopsis. In most cases, maize circRNAs were negatively correlated with sRNA accumulation. In 368 maize inbred lines, the circRNA-hosting genes were enriched for SNPs associated with circRNA expression and drought tolerance, implying either important roles of circRNAs in maize drought responses or their potential use as biomarkers for breeding drought-tolerant maize. Additionally, the expression levels of circRNAs derived from drought-responsible genes encoding calcium-dependent protein kinase and cytokinin oxidase/dehydrogenase were significantly associated with drought tolerance of maize seedlings. Specifically, Arabidopsis plants overexpressing circGORK (Guard cell outward-rectifying K+-channel) were hypersensitive to ABA, but insensitive to drought, suggesting a positive role of circGORK in drought tolerance. We report the transcriptomic profiling and transgenic studies of circRNAs in plant drought responses, and provide evidences highlighting the universal molecular mechanisms involved in plant drought tolerance.
Project description:MicroRNAs (miRNAs) are a class of small, non-coding regulatory RNAs that regulate gene expression by guiding target mRNA cleavage or translational inhibition in plants and animals. At present there is relatively little information regarding the role of miRNAs in the response to drought stress in maize. In this study, two small RNA libraries were sequenced, and a total of 11,973,711 and 14,326,010 raw sequences were generated from growing leaves of drought-tolerant and drought-sensitive maize seedlings, respectively. Further analysis identified 192 mature miRNAs, which include 124 known maize (zma) miRNAs and 68 potential novel miRNA candidates. Additionally, 167 target genes (259 transcripts) of known and novel miRNAs were predicted to be differentially expressed between two maize inbred lines. Of these, three novel miRNAs were up-regulated and two were down-regulated under drought stress. The expression of these five miRNAs and nine target genes was confirmed using quantitative reverse transcription PCR. The expression of three of the miRNAs and their putative target genes exhibited an inverse correlation, and expression analysis suggested that all five may play important roles in maize leaves. Finally, GO annotations of the target genes indicated a potential role in photosynthesis, may therefore contribute to the drought stress response. This study describes the identification and characterization of novel miRNAs that are the differentially expressed in drought-tolerant and drought-sensitive inbred maize lines. This provides the foundation for further investigation into the mechanism of miRNA function in response to drought stress in maize.
Project description:ZmDREB2A is a DREB2-type transcription factor cloned from maize, whose transcript was upregulated by drought, high salt, low temperature and heat stresses. The ZmDREB2A gene possesses two kinds of transcription forms by alternative splicing. Only the functional form was studied to be highly induced by stresses. Transgenic plants overexpressing ZmDREB2A (35S:ZmDREB2A) showed dwarfism and enhanced drought stress tolerance. Microarray analysis of two independent transgenic plants revealed that in addition to genes encoding LEA proteins, some genes related to heat shock and detoxification were also upregulated. Experiments on termotolerance tests of these transgenic plants showed overexpressing ZmDREB2A gene also improved plant tolerance to heat stress.
Project description:This was a comparative transcriptome analysis by using high throughput sequencing. To assess the effects of heat stress on maize we used a controlled environment facility called the Enviratron to simulate field conditions. For our experiments, maize plants were subjected to conditions simulating normal diurnal rhythms of light and temperature, with increasing maximal daily temperature (MDT). Maize plants were grown continuously under four different temperature regimes with simulated morning temperatures ramped up over 6 hr to the MDT of 31°C, 33°C, 35°C or 37°C and simulated evening/night time temperatures ramped down over 8 hr to 10°C below the MDT. We tracked the gene expression events of maize W22 seedlings grow under different temperatures (MDT of 31°C, 33°C, 35°C or 37°C) to evaluate how different MDTs affect the program of gene expression in maize. At the same time, we analyzed the effects of temperature on gene expression in bzip60-2 and W22 V4 plants (20 DAG) and V5 plants (27 DAG) in the Enviratron as the temperature reached its MDT to investigate whether and how bZIP60 confers heat stress tolerance in maize. RNA was extracted from small strips of leaf lamina excised from the first fully expanded leaf of V4 and V5 W22 plants (at 20 and 27 DAG, respectively). Plants were sampled in triplicates.
Project description:Results: In this study, the ears at the V9 stage, kernels and ear leaf at the 5DAP (days after pollination) stage of maize were used for morphological, physiological and comparative transcriptomics analysis to understand the different features of “sink” or “source” organs and the effects on kernel yield under drought stress conditions. The ABA-, NAC-mediate signaling pathway, osmotic protective substance synthesis and protein folding response were identified as common drought stress response in the three organs. Tissue-specific drought stress responses and the regulators were identified, they were highly correlated with growth, physiological adaptation and yield loss under drought stress. For ears, drought stress inhibited ear elongation, led to the abnormal differentiation of the paired spikelet, and auxin signaling involved in the regulation of cell division and growth and primordium development changes. In the kernels, reduced kernel size caused by drought stress was observed, and the obvious differences of auxin, BR and cytokine signaling transduction appeared, which indicated the modification in carbohydrate metabolism, cell differentiation and growth retardation. For the ear leaf, dramatically and synergistically reduced the expression of photosynthesis genes were observed when suffered from drought stress, the ABA- and NAC- mediate signaling pathway played important roles in the regulation of photosynthesis. Conclusions: Transcriptomic changes caused by drought were highly correlated with developmental and physiological adaptation, which was closely related to the final yield of maize, and a sketch of tissue- and developmental stage-specific responses to drought stress in maize was drafted.