97 research outputs found
Plant Single Cell Type Systems Biology
Get PDFThe phenotype of a plant in response to a stress condition is the reflection of the molecular responses in different cell-types composing the plant. The multicellular complexity represents a challenge when accessing specific responses of each cell or cell type composing the plant. To overcome this difficulty and allow the clear characterization of the plant cell molecular mechanisms, the research community is now focusing on studying a single cell and single cell-types. The isolation of plant single cells is limited by the cell wall that confers the rigidity of the plant and its overall structure. Various methods have been developed for isolating plant cells (e.g. laser capture microdissection; cell sorting of Green Fluorescent Protein (GFP)-tagged protoplasts, differential protoplastization of cells such as guard cells, isolation of easily accessible cell types such as cotton fiber, pollen cells, trichomes and root hair cells). The development of these innovative approaches to isolate single plant cells or cell-types combined with the application of sensitive and high-throughput technologies allows a better analysis of the developmental processes and response to environmental stresses. Ultimately, single plant cell and cell-type biology will lead to establishment of more reliable and accurate -molecular regulatory networks at the resolution of basic life unit. The goal of this Research Topic is to cover new technological and biological advances in the study of plant single cell, cell-type and systems biology
Transcriptional Reprogramming of Legume Genomes: Perspective and Challenges Associated With Single-Cell and Single Cell-Type Approaches During Nodule Development
Get PDFTranscriptomic approaches revealed thousands of genes differentially or specifically expressed during nodulation, a biological process resulting from the symbiosis between leguminous plant roots and rhizobia, atmospheric nitrogen-fixing symbiotic bacteria. Ultimately, nodulation will lead to the development of a new root organ, the nodule. Through functional genomic studies, plant transcriptomes have been used by scientists to reveal plant genes potentially controlling nodulation. However, it is important to acknowledge that the physiology, transcriptomic programs, and biochemical properties of the plant cells involved in nodulation are continuously regulated. They also differ between the different cell-types composing the nodules. To generate a more accurate picture of the transcriptome, epigenome, proteome, and metabolome of the cells infected by rhizobia and cells composing the nodule, there is a need to implement plant single-cell and single cell-types strategies and methods. Accessing such information would allow a better understanding of the infection of plant cells by rhizobia and will help understanding the complex interactions existing between rhizobia and the plant cells. In this mini-review, we are reporting the current knowledge on legume nodulation gained by plant scientists at the level of single cell-types, and provide perspectives on single cell/single cell-type approaches when applied to legume nodulation
New Insights into Mechanisms of Epigenetic Modifiers in Plant Growth and Development
No full textThis eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contac
Transcriptional Reprogramming of Legume Genomes: Perspective and Challenges Associated With Single-Cell and Single Cell-Type Approaches During Nodule Development
Get PDFTranscriptomic approaches revealed thousands of genes differentially or specifically expressed during nodulation, a biological process resulting from the symbiosis between leguminous plant roots and rhizobia, atmospheric nitrogen-fixing symbiotic bacteria. Ultimately, nodulation will lead to the development of a new root organ, the nodule. Through functional genomic studies, plant transcriptomes have been used by scientists to reveal plant genes potentially controlling nodulation. However, it is important to acknowledge that the physiology, transcriptomic programs, and biochemical properties of the plant cells involved in nodulation are continuously regulated. They also differ between the different cell-types composing the nodules. To generate a more accurate picture of the transcriptome, epigenome, proteome, and metabolome of the cells infected by rhizobia and cells composing the nodule, there is a need to implement plant single-cell and single cell-types strategies and methods. Accessing such information would allow a better understanding of the infection of plant cells by rhizobia and will help understanding the complex interactions existing between rhizobia and the plant cells. In this mini-review, we are reporting the current knowledge on legume nodulation gained by plant scientists at the level of single cell-types, and provide perspectives on single cell/single cell-type approaches when applied to legume nodulation
The Carbon-Nitrogen Balance of the Nodule and Its Regulation under Elevated Carbon Dioxide Concentration
Get PDFLegumes have developed a unique way to interact with bacteria: in addition to preventing infection from pathogenic bacteria like any other plant, legumes also developed a mutualistic symbiotic relationship with one gender of soil bacteria: rhizobium. This interaction leads to the development of a new root organ, the nodule, where the differentiated bacteria fix for the plant the atmospheric dinitrogen (atmN2). In exchange, the symbiont will benefit from a permanent source of carbon compounds, products of the photosynthesis. The substantial amounts of fixed carbon dioxide dedicated to the symbiont imposed to the plant a tight regulation of the nodulation process to balance carbon and nitrogen incomes and outcomes. Climate change including the increase of the concentration of the atmospheric carbon dioxide is going to modify the rates of plant photosynthesis, the balance between nitrogen and carbon, and, as a consequence, the regulatory mechanisms of the nodulation process. This review focuses on the regulatory mechanisms controlling carbon/nitrogen balances in the context of legume nodulation and discusses how the change in atmospheric carbon dioxide concentration could affect nodulation efficiency
New Insights into Mechanisms of Epigenetic Modifiers in Plant Growth and Development
No full textThis eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contac
Géographie et Prospective
No full textAbstract. - Discussing first of the ways permitting the application of the prospective methods in the geographical research, the author emphasises a graphical analysis permitting a very synthetic approach.Abstract. - Discussing first of the ways permitting the application of the prospective methods in the geographical research, the author emphasises a graphical analysis permitting a very synthetic approach.Libault André. Géographie et Prospective. In: Bulletin de l'Association de géographes français, N°441-442, 54e année, Mars-avril 1977. pp. 133-137
GENETIC AND GENOMIC ANALYSIS OF BAHD ACYLTRANSFERASES THAT DECORATE CELL WALL COMPONENTS WITH PHENOLIC ESTERS AND ALTER PLANT BIOMASS RECALCITRANCE
Get PDFNext generation biofuels make use of the energy stored in plant cell walls, so called lignocellulosic biomass. However, the natural resistance of plant cell walls against deconstruction, i.e., “cell wall recalcitrance”, poses a significant challenge to large-scale commercialization of lignocellulosic biofuels. Grasses, including cereal crops and perennial grasses, are the major source of terrestrial biomass. Previous studies have implicated phenolic acids (ferulic acid and p-coumaric acid) in grass cell wall recalcitrance, but the enzymes that attach these molecules to cell wall precursors are largely unknown. To address this gap, this dissertation accomplished the following: 1) genetic characterization of two so-called “BAHD” acyltransferase genes from rice (Oryza sativa, Os), OsAT5 and OsAT9; 2) examination of the impact of feruloylated lignin on biomass recalcitrance; 3) exploration of cell wall recalcitrance genes in the bioenergy crop, switchgrass, via transcriptomics.
To study the enzymes involved in FA decoration in cell walls, we overexpressed a BAHD -coenzyme A acyltransferase, encoded by the OsAT5 gene, in rice and found increased incorporation of feruloyl monolignol conjugates (ML-FAs) in lignin. Cell wall chemical and gene sequence phylogenetic analysis of gymnosperms, dicotyledonous and monocotyledonous plants revealed that incorporation of ML-FAs is wide-spread in angiosperms, but those orthologous genes to OsAT5 are only present in grasses and other commelinid monocot species. These results suggest that angiosperms have convergently evolved the ability to synthesize this newly recognized conjugated lignin precursor.
To verify the enzymatic activity and the role of OsAT5 in cell wall decoration, we heterologously expressed the OsAT5 gene in yeast and Arabidopsis, which naturally lack monolignol ferulates. Contrasting the cell wall properties of wild type and transgenic OsAT5 overexpression-rice (Ubipro-OsAT5) and -Arabidopsis (C4Hpro-OsAT5) revealed that, 1) transgenic Arabidopsis exhibited reduced cell wall recalcitrance, whereas transgenic rice lines did not; 2) compared with transgenic rice, transgenic Arabidopsis has a more significant impact on sinapyl ferulate (S-FA) incorporation; 3) when treated with alkaline, wild-type rice lignin, which naturally possesses ML-FA conjugates, shows a higher solubility than wild-type Arabidopsis lignin, consistent with grasses having a more chemically-labile lignin polymer than dicots. The discordant observations in rice and Arabidopsis indicate that ML-FAs produced by OsAT5 have differential impacts on cell wall traits depending on the plant species and tissue, raising the possibility of tailoring lignin structure engineering to different species to tune biomass recalcitrance.
To reveal other mechanisms of feruloylation in grasses, we genetically characterized another BAHD acyltransferase, OsAT9, in rice. Overexpression of OsAT9 in rice with the maize Ubi promoter increased the ratio of ferulic acid to p-coumaric acid (FA:pCA) in cell wall polysaccharides and improved extractability of xylan with base treatment, but reduced the enzymatic digestibility of the leaf and stem. These results suggest that OsAT9 is a strong candidate as a feruloyl arabinosyl transferases responsible for feruloylation of rice arabinoxylan by which biomass recalcitrance can be altered.
The important agricultural and industrial use of the perennial grass, switchgrass, has generated particular interest in dissecting biomass digestibility-related genes. To accomplish this, we conducted RNA sequencing of four switchgrass genotypes with distinct digestibility, including four sample types (whole elongation 4-stage tiller, leaf, soft stem, and hard stem). The transcriptomes allowed dissection of tissue-specific, lignin biosynthesis- and biomass digestibility-associated genes. We discovered that some protein kinases and cell wall biosynthesis genes are highly related to biomass digestibility and also noted subfunctionalization of putative cell wall-decorating BAHD acyltransferase and lignin biosynthesis genes.
This dissertation significantly expands knowledge of cell wall decoration by ferulates, provides insight into the functions of BAHD acyltransferase gene family members and their impacts on cell wall synthesis and biomass recalcitrance in both model plants and food and energy crop species. This study also provides valuable information and new ideas for plant breeding and engineering to create less recalcitrant plant biomass for industrial use and animal forage
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