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Biomedical subjects

Siobhan M Brady

Publications and source records attributed to Siobhan M Brady.

4 recordsLinked to original sources
PubMed2025

Decoding nitrogen uptake efficiency in maize and sorghum: insights from comparative gene regulatory networks.

Nitrogen (N) is an essential macronutrient for plant growth and yield, yet optimizing nitrogen use efficiency remains a challenge in agriculture. To better understand the regulatory basis of plant responses to N availability, we constructed a maize-specific nitrogen uptake efficiency gene regulatory network (mNUEGRN) comprising 1625 protein-DNA interactions (PDI) between 70 promoters and 301 transcription factors using enhanced yeast one-hybrid assays. We also projected a sorghum NUE GRN (spNUEGRN) based on maize orthologs and analyzed N-responsive subnetworks in both species using transcriptome profiling under N stress of early deprivation and recovery. Cross-species comparison with an existing Arabidopsis GRN revealed about 18% conserved interaction, corresponding to 11% of the mNUEGRN, particularly within the nitrate assimilation pathways. Notably, bZIP18 and bZIP30 emerged as central regulators in mNUEGRN, forming highly connected feed-forward loops (FFLs). From our time series data, we identified 19 236 and 23 864 differentially expressed genes in maize and sorghum, respectively. Gini correlation analysis uncovered 764 and 638 FFLs in mNUEGRN and spNUEGRN, respectively, of which 22 FFLs in maize and 35 in sorghum were identified in both leaf and root for each species. These FFLs may represent candidate regulatory motifs that contribute to modulating transcriptional responses under fluctuating N conditions, but their potential roles require further investigation. Together, our findings reveal evolutionarily conserved and species-specific regulatory strategies that mediate early N responsiveness, offering a foundation for engineering crops with improved NUE.

Sorghum↗
PubMed2006

Combining expression and comparative evolutionary analysis. The COBRA gene family.

Plant cell shape is achieved through a combination of oriented cell division and cell expansion and is defined by the cell wall. One of the genes identified to influence cell expansion in the Arabidopsis (Arabidopsis thaliana) root is the COBRA (COB) gene that belongs to a multigene family. Three members of the AtCOB gene family have been shown to play a role in specific types of cell expansion or cell wall biosynthesis. Functional orthologs of one of these genes have been identified in maize (Zea mays) and rice (Oryza sativa; Schindelman et al., 2001; Li et al., 2003; Brown et al., 2005; Persson et al., 2005; Ching et al., 2006; Jones et al., 2006). We present the maize counterpart of the COB gene family and the COB gene superfamily phylogeny. Most of the genes belong to a family with two main clades as previously identified by analysis of the Arabidopsis family alone. Within these clades, however, clear differences between monocot and eudicot family members exist, and these are analyzed in the context of Type I and Type II cell walls in eudicots and monocots. In addition to changes at the sequence level, gene regulation of this family in a eudicot, Arabidopsis, and a monocot, maize, is also characterized. Gene expression is analyzed in a multivariate approach, using data from a number of sources, including massively parallel signature sequencing libraries, transcriptional reporter fusions, and microarray data. This analysis has revealed that the expression of Arabidopsis and maize COB gene family members is highly developmentally and spatially regulated at the tissue and cell type-specific level, that gene superfamily members show overlapping and unique expression patterns, and that only a subset of gene superfamily members act in response to environmental stimuli. Regulation of expression of the Arabidopsis COB gene family members has highly diversified in comparison to that of the maize COB gene superfamily members. We also identify BRITTLE STALK 2-LIKE 3 as a putative ortholog of AtCOB.

Amino Acid Sequence↗
PubMed2005

The Botany Array Resource: e-Northerns, Expression Angling, and promoter analyses.

The Botany Array Resource provides the means for obtaining and archiving microarray data for Arabidopsis thaliana as well as biologist-friendly tools for viewing and mining both our own and other's data, for example, from the AtGenExpress Consortium. All the data produced are publicly available through the web interface of the database at http://bbc.botany.utoronto.ca. The database has been designed in accordance with the Minimum Information About a Microarray Experiment convention -- all expression data are associated with the corresponding experimental details. The database is searchable and it also provides a set of useful and easy-to-use web-based data-mining tools for researchers with sophisticated yet understandable output graphics. These include Expression Browser for performing 'electronic Northerns', Expression Angler for identifying genes that are co-regulated with a gene of interest, and Promomer for identifying potential cis-elements in the promoters of individual or co-regulated genes.

Arabidopsis↗