Project description:Transcriptional profiling of 4 maize varieties comparing genetic root response under control temperature conditions with genetic root response under low temperature conditions
Project description:Development of crop varieties with high nitrogen use efficiency (NUE) is crucial for minimizing N loss, reducing environmental pollution and decreasing input cost. Maize is one of the most important crops cultivated worldwide and its productivity is closely linked to the amount of fertilizer used. A survey of the transcriptomes of shoot and root tissues of a maize hybrid line and its two parental inbred lines grown under sufficient and limiting N conditions by mRNA-Seq has been conducted to have a better understanding of how different maize genotypes respond to N limitation.
Project description:Investigation of whole genome gene expression level changes in maize plants (standard maize line B73) in controlled conditions under continuous light. Tissues of the leaf elongation zone were sampled from plants well watered every 12 hours before and after lights on.
Project description:Nitrate (NO3-) is crucial for optimal plant growth and development and often limits crop productivity at the low availability. In comparison with model plant Arabidopsis, the molecular mechanisms underlying NO3- acquisition and utilization remain largely unclear in maize. In particular, only a few genes have been exploited to improve nitrogen use efficiency (NUE). Here, we demonstrated that NO3--inducible ZmNRT1.1B (ZmNPF6.6) positively regulated NO3--dependent growth and NUE in maize. We showed that the tandem duplicated proteoform ZmNRT1.1C is irrelevant to maize seedling growth under nitrate supply, however, loss-of-function of ZmNRT1.1B significantly weakened plant growth under adequate NO3- supply in both hydroponic and field conditions. 15N-labeled NO3- absorption assay indicated that ZmNRT1.1B mediated high-affinity NO3--transport and root-to-shoot NO3- translocation. Furthermore, upon NO3- supply, ZmNRT1.1B promotes cytoplasmic-to-nuclear shuttling of ZmNLP3.1 (ZmNLP8), which co-regulates the expression of genes involved in NO3- response, cytokinin biosynthesis and carbon metabolism. Remarkably, overexpression of ZmNRT1.1B in modern maize hybrids improved grain yield under nitrogen (N) limiting fields. Taken together, our study revealed a crucial role of ZmNRT1.1B in high-affinity NO3- transport and signaling and offers valuable genetic resource for breeding nitrogen use efficient high-yield cultivars.
Project description:In this study a transcriptomic approach (RNA-sequencing) was utilized to elucidate molecular responses of maize (Zea mays L.) primary roots of the inbred line B73 to water deficit to gain a better understanding of the mechanisms underlying drought tolerance. Kernels of the maize inbred line B73 were germinated in paper rolls soaked with distilled water until seedlings had a primary root length of 2 to 4 cm. For mild and severe water deficit conditions, seedlings were transferred to PEG8000 solution with water potentials of -0.2 MPa and -0.8 MPa, respectively. Water deficit treatment was applied for 6 h and 24 h. Each treatment was performed in four biological replicates each consisting of 10 roots.
Project description:The basidiomycete fungus Ustilago maydis causes smut disease in maize and has become an important model for elucidating the strategies used for host colonization by biotrophic fungi. In this study, we performed an in-depth transcriptional profiling of the plant-associated development of a cross between U. maydis FB1 and FB2 wildtype strains. The analysis of eight different stages, including the development on the leaf surface, early colonization, tumor induction and spore maturation, offers an unprecedented view of the changes in the fungal transcriptome associated with the passage through the entirely biotrophic life cycle. In our analysis, we focus on fungal metabolism, nutritional strategies, secreted effectors and regulatory networks. Secreted proteins were enriched in three distinct expression modules corresponding to the plant surface, establishment of biotrophy and tumor formation, respectively. These modules are likely the key determinants for U. maydis virulence. With respect to nutrient utilization, we observed that expression of several nutrient transporters was tied to these virulence modules rather than being controlled by nutrient availability. We show that oligopeptide transporters likely involved in nitrogen supply during infection are important virulence determinants. By measuring the intramodular connectivity of transcription factors, we identified potential drivers for the virulence modules. While known components of the b-cascade served as inducers for the plant surface and biotrophy module, we identified a set of yet uncharacterized transcription factors as likely responsible for expression of the tumor module. We demonstrate a crucial role in effector gene expression and tumor formation for one of these transcription factors.
Project description:Maize transgenic event MON810, grown and commercialised worldwide, is the only cultivated GM event in EU. Maize MON810, variety DKC6575, and the corresponding near-isogenic Tietar were studied in different growing conditions, to assess their behaviour in response to drought. Profiling gene expression in water deficit regimes and in generalised water stress showed an up-regulation of different stress- responsive genes. A greater number of differentially expressed genes was observed in Tietar rather than in DKC6575, with genes belonging to transcription factor families and genes encoding HSPs, LEAs and detoxification enzymes. Since these genes have been from literature, indicated as typical of stress responses, their activation in Tietar rather than in DKC6575 may be reminiscent of a more efficient water stress response. DKC6575 was also analysed for the expression of the transgene CryIAb (encoding for the delta-endotoxin insecticidal protein) in water limiting conditions. In all the experiments the CryIAb transcript was not influenced by water stress, but expressed at a constant level. This suggests that though a different pattern of sensitivity to stress, the transgenic variety maintains the same expression level for the transgene.