Project description:<p>Cold stress negatively affects maize (<em>Zea mays</em> L.) growth, development and yield. Metabolic adjustments contribute to the adaptation of maize under cold stress. We show here that the transcription factor INDUCER OF CBF EXPRESSION 1 (ZmICE1) plays a prominent role in reprogramming amino acid metabolome and <em>COLD-RESPONSIVE</em> (<em>COR</em>) genes during cold stress in maize. Derivatives of amino acids glutamate/asparagine (Glu/Asn) induce a burst of mitochondrial reactive oxygen species, which suppress the cold-mediated induction of <em>DEHYDRATION RESPONSE ELEMENT-BINDING PROTEIN 1</em> (<em>ZmDREB1</em>) genes and impair cold tolerance. ZmICE1 blocks this negative regulation of cold tolerance by directly repressing the expression of the key Glu/Asn biosynthesis genes, <em>ASPARAGINE SYNTHETASEs</em>. Moreover, ZmICE1 directly regulates the expression of <em>DREB1s</em>. Natural variation at the <em>ZmICE1</em> promoter determines the binding affinity of the transcriptional activator ZmMYB39, a positive regulator of cold tolerance in maize, resulting in different degrees of <em>ZmICE1</em> transcription and cold tolerance across inbred lines. This study thus unravels a mechanism of cold tolerance in maize and provides potential targets for engineering cold-tolerant varieties.</p>
Project description:We report the application of single-molecule-based sequencing technology for high-throughput profiling of transcriptome in mazie plants. The ZmPIS gene coding PtdIns synthase from maize with a maize ubiquitin promoter was transferred into maize. The transgenic ZmPIS maize showed enhanced drought tolerance compared to non-transgenic maize. The differentially expressed genes between wide-type maize and transgenic ZmPIS maize were detected by the assay of digital gene expression profile and real time RT-PCR datas. The results displayed that the overexpression of ZmPIS resulted in the expression levels changes of a large number of genes including genes involved in the phosphatidylinositol (PI) metabolic pathway, photosynthesis metabolism, carbohydrate metabolism, aminoacid metabolism and genes coding transcription factors.
Project description:Maize is highly sensitive to short term flooding and submergence. We aimed to discover genetic variation for submergence tolerance in maize and elucidate the genetic basis of submergence tolerance through transcriptional profiling of contrasting genotypes. A diverse set of maize nested association mapping (NAM) founder lines were screened, and two highly tolerant (Mo18W and M162W) and sensitive (B97 and B73) genotypes were identified. Transcriptome analysis was performed on these inbreds to provide genome level insights into the molecular responses to submergence.
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:To investigate the role of melatonin in salt tolerance of maize, we determine the seed germinated rate of maize under CK, NaCl and NaCl+melatonin. We then performed miRNA profiling analysis using data obtained from miRNA-seq of the seeds of three different treatments.
Project description:To investigate the role of melatonin in salt tolerance of maize, we determine the seed germinated rate of maize under CK, NaCl and NaCl+melatonin. We then performed gene expression profiling analysis using data obtained from RNA-seq of the seeds of three different treatments.
Project description:We report the application of single-molecule-based sequencing technology for high-throughput profiling of transcriptome in mazie plants. The ZmPIS gene coding PtdIns synthase from maize with a maize ubiquitin promoter was transferred into maize. The transgenic ZmPIS maize showed enhanced drought tolerance compared to non-transgenic maize. The differentially expressed genes between wide-type maize and transgenic ZmPIS maize were detected by the assay of digital gene expression profile and real time RT-PCR datas. The results displayed that the overexpression of ZmPIS resulted in the expression levels changes of a large number of genes including genes involved in the phosphatidylinositol (PI) metabolic pathway, photosynthesis metabolism, carbohydrate metabolism, aminoacid metabolism and genes coding transcription factors. Examination of The differences of the transcriptional profile between wide-type maize and transgenic ZmPIS maize and analysis of the network regulated by the ZmPIS gene
Project description:Maize is highly sensitive to short term flooding and submergence. We aimed to discover genetic variation for submergence tolerance in maize and elucidate the genetic basis of submergence tolerance through transcriptional profiling of contrasting genotypes. A diverse set of maize nested association mapping (NAM) founder lines were screened, and two highly tolerant (Mo18W and M162W) and sensitive (B97 and B73) genotypes were identified. Transcriptome analysis was performed on these inbreds to provide genome level insights into the molecular responses to submergence. RNA deep sequencing of shoot tissue from four inbreds (B73, B97, Mo18W and M162W) in three conditions 24h control (non-submerged), 24h submerged and 72h submerged.
Project description:BACKGROUND: Climate change will lead in the future to an occurrence of heat waves with a higher frequency and duration than observed today, which has the potential to cause severe damage to seedlings of temperate maize genotypes. In this study, we aimed to (I) assess phenotypic variation for heat tolerance of temperate European Flint and Dent maize inbred lines, (II) investigate the transcriptomic response of temperate maize to linearly increasing heat levels and, (III) identify genes associated with heat tolerance in a set of genotypes with contrasting heat tolerance behaviour. RESULTS: Strong phenotypic differences with respect to heat tolerance were observed between the examined maize inbred lines on a multi-trait level. We identified 607 heat responsive genes as well as 39 heat tolerance genes. CONCLUSION: Our findings indicate that individual inbred lines developed different genetic mechanisms in response to heat stress. We applied a novel statistical approach enabling the integration of multiple genotypes and stress levels in the analysis of abiotic stress expression studies.
Project description:Drought represents a major constraint on maize production worldwide. Understanding the genetic basis for natural variation in drought tolerance of maize may facilitate efforts to improve this trait in cultivated germplasm. Here, using a genome-wide association study, we show that a miniature inverted-repeat transposable element (MITE) inserted in the promoter of a NAC gene (ZmNAC111) is significantly associated with natural variation in maize drought tolerance. For maize RNA-seq analysis, pooled tissues from three, eight-day-old maize seedlings were collected from transgenic and wild-type plants, prior to or after 2-hour dehydration, to conduct the RNA-seq analysis.