Project description:The biological functions of circadian clock on growth and development have been well elucidated in model plants, while its regulatory roles in crop species, especially the roles on yield-related traits are poorly understood. Here, we characterize the core clock gene CCA1 homoeologs in wheat and studied their biological functions in seedling growth and spike development. TaCCA1 homoeologs exhibit typical diurnal expression patterns which are positively regulated by rhythmic histone modifications (H3K4me3, H3K9ac and H3k36me3). TaCCA1s are preferentially located in the nucleus and tend to form both homo- and heterodimers. TaCCA1 overexpression (TaCCA1-OE) transgenic wheat plants show disrupted circadian rhythmicity coupling with reduced chlorophyll and starch content, as well as biomass at seedling stage, also decreased spike length, grain number per spike and grain size at the ripening stage. Further studies using DNA affinity purification followed by deep sequencing (DAP-seq) indicates that TaCCA1 preferentially binds to sequences similar to “evening elements” (EE) motif in the wheat genome, particularly genes associated with photosynthesis, carbon utilization and auxin homeostasis, and decreased transcriptional levels of these target genes are observed in TaCCA1-OE transgenic wheat plants. Collectively, our study provides novel insights into a circadian-mediated mechanism of gene regulation to coordinate photo synthetic and metabolic activities in wheat, which is important for optimal plant growth and crop yield formation.
Project description:Our understanding of the mechanisms that govern the cellular process of meiosis is limited in higher plants with polyploid genomes. Bread wheat is an allohexaploid that behaves as a diploid during meiosis. Chromosome pairing is restricted to homologous chromosomes despite the presence of homoeologues in the nucleus. The importance of wheat as a crop and the extensive use of wild wheat relatives in breeding programs has prompted many years of cytogenetic and genetic research to develop an understanding of the control of chromosome pairing and recombination. The rapid advance of biochemical and molecular information on meiosis in model organisms such as yeast provides new opportunities to investigate the molecular basis of chromosome pairing control in wheat. However, building the link between the model and wheat requires points of data contact. We report here a large-scale transcriptomics study using the Affymetrix wheat GeneChip® aimed at providing this link between wheat and model systems and at identifying early meiotic genes. Analysis of the microarray data identified 1,350 transcripts temporally-regulated during the early stages of meiosis. Expression profiles with annotated transcript functions including chromatin condensation, synaptonemal complex formation,recombination and fertility were identified. From the 1,350 transcripts, 30 displayed at least an eight-fold expression change between and including pre-meiosis and telophase II, with more than 50% of these having no similarities to known sequences in NCBI and TIGR databases. This resource is now available to support research into the molecular basis of pairing and recombination control in the complex polyploid, wheat. Experiment Overall Design: The seven stages collected were pre-meiosis (PM), leptotene to pachytene (LP), diplotene to anaphase I (DA), telophase I to telophase II (TT), tetrads (T), immature pollen (IP) and mature anthers (MAN). Immediately after determining the stage, the remaining two anthers from the floret were placed into liquid nitrogen. After collecting at least 25 staged anthers for each time point from several biological samples, anthers from the respective stages were pooled. Leaf material used in this study was collected from glasshouse-grown plants (six weeks) and total RNA isolated using Trizol® (Gibco BRL, Australia) according to the manufacturerâs protocol. Experiment Overall Design: Twenty micrograms of aRNA of from each of the seven samples were fragmented for hybridization to each microarray. In total three technical replicates were conducted for each of the seven stages examined. Affymetrix GeneChip® Wheat Genome Arrays were used for all samples. The arrays were hybridized and processed according to the manufacturerâs specifications. Experiment Overall Design: Normalization of the microarray data was conducted using RMA. The software package Acuity 4 (Molecular Devices, CA, USA) was then used to analyze the microarray data.
Project description:Background: The soil environment is responsible for sustaining most terrestrial plant life on earth, yet we know surprisingly little about the important functions carried out by diverse microbial communities in soil. Soil microbes that inhabit the channels of decaying root systems, the detritusphere, are likely to be essential for plant growth and health, as these channels are the preferred locations of new root growth. Understanding the microbial metagenome of the detritusphere and how it responds to agricultural management such as crop rotations and soil tillage will be vital for improving global food production. Methods: The rhizosphere soils of wheat and chickpea growing under + and - decaying root were collected for metagenomics sequencing. A gene catalogue was established by de novo assembling metagenomic sequencing. Genes abundance was compared between bulk soil and rhizosphere soils under different treatments. Conclusions: The study describes the diversity and functional capacity of a high-quality soil microbial metagenome. The results demonstrate the contribution of the microbiome from decaying root in determining the metagenome of developing root systems, which is fundamental to plant growth, since roots preferentially inhabit previous root channels. Modifications in root microbial function through soil management, can ultimately govern plant health, productivity and food security.
Project description:Wheat panicle development is a coordinated process of proliferation and differentiation with distinctive phase and architecture changes. However, the multiple genes involved networks controlling this process remain enigmatic. Here, we characterized and dissected common wheat panicles in the stages of vegetative stage before elongation, elongation, single ridge, double ridge, glume primodium differentiation and floret differentiation, respectively, followed by RNA-seq and bioinformatics analysis to study genome-wide mRNA transcriptome profiling in wheat early spike development. High gene expression correlations between any two stages (R2>0.97) and only 4000 Differentially Expressed Genes (DEGs) out of 49624 expressed transcripts in all stages indicated that wheat early panicle development is just controlled by an small proportion of important genes. Three subgenomes (A, B and D) contribute equally to this process. K-means clustering analysis revealed the dynamic expression patterns of DEGs and Hierarchical Clustering analysis demonstrated that single bridge stage and double bridge stage are most important for wheat panicle development. Interestingly, 306 transcription factors (TFs) with various functions from different families were identified and the spatial-temporal expression patterns of some were verified by quantitative PCR or in situ hybridization. At early stages, repressing flowering TFs combined with AP2/ERF TFs and cytokinin promote inflorescence meristem development and repress meristem differentiation. At single ridge and double ridge stages, highly expressed stress-response TFs balance the interaction between stress response and development. During reproductive stages, crosstalk between auxin and cytokinin coordinate the meristem proliferation and differentiation, and promoting flowering TFs with polarity establishment TFs and MADS-box TFs promote floral meristem generation and floral organ identity and development. This dataset provided an ideal resource for wheat panicle developmental research. Our study uncovered the regulatory network for coordinated wheat early spike development and would eventually contribute to the improvement of grain number and crop yield.
Project description:To study the expression profiles of hexaploid wheat chromosome 3B genes during the life cycle of a wheat plant and establish a transcriptome atlas for this chromosome, deep transcriptome sequencing was conducted in duplicates in 15 wheat samples corresponding to five different organs (leaf, shoot, root, spike, and grain) at three developmental stages each. Strand-non-specific and strand-specific libraries were used to produce 2.52 billion paired-end reads (232 Gb) and 615.3 single-end reads (62 Gb), respectively.
Project description:Barley contains a much higher content of bioactive substances than wheat. In order to investigate the effect of genome interaction between barley and wheat on phytosterol content, we used a series of barley chromosome addition lines of common wheat. The wheat 38k-microarray was utilized for screening of genes with expression levels specifically increased by an additive effect or synergistic action between wheat and barley chromosomes. We determined the overall expression pattern of genes related to phytosterol biosynthesis in wheat and in each addition line. Together with determining the phytosterol levels of wheat, barley and each addition line, we assess the critical genes in the phytosterol pathway that can be expressed to promote phytosterol levels.
Project description:The economic importance of wheat and its contribution to human and livestock diets has been already demonstrated. However, wheat production is impacted by pests that induce yield reductions. Among these pests, wheat curl mite (WCM, Aceria tosichella Keifer) impacts wheat all around the world. WCM are tiny pests that feed within the whorl of developing leaves and prevent the leaves from unfurling by causing leaves curling. The curling of the leaves provides a protective niche for the WCM. Additionally, WCM are also the vector of serious viruses in wheat. Little is known regarding the impact of the WCM on wheat transcriptome, and to date, only one article has been published describing the wheat transcriptomic changes after 1 day of WCM feeding. To better understand the wheat transcriptome variation after long-term feeding by WCM (10 days post infestation (dpi)), we used an RNA-seq approach. We collected leaves uninfested and infested with WCR from two wheat cultivars: Byrd (WCM resistant) and Settler CL (WCM susceptible) at 10 dpi. Our transcriptomic analysis revealed the common and specific transcriptomic variations in WCM resistant and susceptible wheat cultivars, chromosome specific location of the differentially expressed genes, and also identified the gene functions and pathways involved in WCM resistance. Collectively, our study provides important insights on wheat defense mechanisms against WCM after long-term feeding.