Project description:Like protein coding genes, loci that produce microRNAs (miRNAs) are generally considered to be under purifying selection, consistent with miRNA polymorphisms being able to cause disease. Nevertheless, it has been hypothesized that variation in miRNA genes may contribute to phenotypic diversity. Here we demonstrate that a naturally occurring polymorphism in the MIR164A gene interacts epistatically with an unlinked locus to affect leaf shape and shoot architecture in Arabidopsis thaliana. A single-base pair substitution in the miRNA complementary sequence alters the stability of the miRNA:miRNA* duplex. It thereby interferes with processing of the precursor and greatly reduces miRNA accumulation. We demonstrate that this is not a rare exception, but that natural strains of Arabidopsis thaliana harbor dozens of similar polymorphisms that affect processing of a wide range of miRNA precursors. Our results suggest that natural variation in miRNA processability due to cis mutations is a common contributor to phenotypic variation in plants.
Project description:Like protein coding genes, loci that produce microRNAs (miRNAs) are generally considered to be under purifying selection, consistent with miRNA polymorphisms being able to cause disease. Nevertheless, it has been hypothesized that variation in miRNA genes may contribute to phenotypic diversity. Here we demonstrate that a naturally occurring polymorphism in the MIR164A gene interacts epistatically with an unlinked locus to affect leaf shape and shoot architecture in Arabidopsis thaliana. A single-base pair substitution in the miRNA complementary sequence alters the stability of the miRNA:miRNA* duplex. It thereby interferes with processing of the precursor and greatly reduces miRNA accumulation. We demonstrate that this is not a rare exception, but that natural strains of Arabidopsis thaliana harbor dozens of similar polymorphisms that affect processing of a wide range of miRNA precursors. Our results suggest that natural variation in miRNA processability due to cis mutations is a common contributor to phenotypic variation in plants. sRNA sequencing transgenic A. thaliana
Project description:Shoot apical meristem (SAM) of higher plant composed of a few distinct cell types. All the cells in a mature plant’s SAM derived from 30~35 stem cells reservoir which are located at the tip of the apex. Plants ability to give rise diverse cell types from a pool of pluripotent stem cells requires orchestrated gene network that controls the cell fate commitment during the meristem development. To understand, how gene regulatory networks control cell identities switches during cell differentiation requires resolution in recording their gene expression pattern at single cell resolution. An earlier expression map involving three-cell population of stem cell niche revealed complex expression pattern among the cell types1. We developed this approach further and report here a gene expression map using cell-sorting methods for fluorescent protein marked cells in Arabidopsis shoot. The map covered 10 cell populations. This gene expression map represents data from 10 different cell types from Arabidopsis SAM. It will be first step in defining the function of many unknown genes in model plant Arabidopsis.
Project description:Plant roots located in the upper soil layers are prone to experience high temperatures. To gain insight into the effect of high temperature on root development and functioning, we exposed five-day-old Arabidopsis thaliana seedlings grown on agar plates to 30 °C for 48 hours, and compared the gene expression profile in the root tip with that from seedlings that remained at 22 °C.
Project description:To gain further insights into a larger number of processes potentially altered by high nickel (Ni), we performed a transcriptional profiling of whole roots of Arabidopsis thaliana accession Columbia-0 (Col-0) exposed to 100 µM nickel, a concentration that induces slight chlorosis and intermediate inhibition of root and shoot growth.
Project description:Injured plant somatic tissues regenerate themselves by establishing the shoot or root meristems. In Arabidopsis (Arabidopsis thaliana) a two-step culture system ensures regeneration by first promoting the acquisition of pluripotency and subsequently specifying the fate of new meristems. Although previous studies have reported the importance of phytohormones auxin and cytokinin in determining the fate of new meristems, it remains elusive whether and how the environmental factors influence this process. In this study, we investigated the impact of light signals on shoot regeneration using Arabidopsis hypocotyl as explants. We found that light signals promote shoot regeneration while inhibiting root formation. ELONGATED HYPOCOTYL 5 (HY5), the pivotal transcriptional factor in light signaling, plays a central role in this process by mediating the expression of key genes controlling the fate of new meristems. Specifically, HY5 directly represses root development genes and activates shoot meristem genes, leading to the establishment of shoot progenitor from pluripotent callus. We further demonstrated that the early activation of photosynthesis is critical for shoot initiation, and this is transcriptionally regulated downstream of the HY5-dependent pathways. In conclusion, we uncovered the intricate molecular mechanisms by which light signals control the establishment of new meristem through the regulatory network governed by HY5, thus, highlighting the influence of light signals on plant developmental plasticity.