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:To identify novel miRNA and NAT-siRNAs that are associated with abiotic stresses in maize, we generated small RNA sequences from maize seedlings that grew under control and under dought, salt, and cold stress treatments. Sequencing of small RNAs in maize under control, drought, salt, and cold stress conditions.
Project description:Sequencing of 46 maize leaf whole transcriptome revealed 77 differentially expressed genes (DEGs) between Lancaster and Non-Lancaster maize genetic resources under optimal growing conditions. Cold test of the subset of four Lancaster and four Non-Lancaster lines showed that the first were cold sensitive and the later cold tolerant, with the majority of identified DEGs showing FPKM values above the plate mean in Lancaster, but below the plate mean in Non-Lancaster subset. Cold induced expression analysis for revealed that, among seven tested DEGs, ATP-sulfurylase and photosystem II I encoding genes showed responsiveness to low temperatures in a genetic-background-dependent manner, likely contributing to different cold response/adaptability of Lancaster and Non-Lancaster lines.
Project description:High-throughput sequencing of genomic regions isolated using FAIRE (Formaldehyde-assisted isolation of regulatory elements) from two maize lines of contrasting cold-sensitivity, S68911 (tolerant) and B73 (sensitive) grown in cold and control conditions. Three growth stages were examined: coleoptile (VE), seedling with the tip of the second leaf visible (called here “VE/V1 stage”), first leaf fully developed (V1, ligular region present). Results suggest both efficient metabolism and active defense mechanisms as a basis of S68911 maize cold-tolerance.