Update on the Structure and Regulated Biosynthesis of the Apoplastic Polymers Cutin and Suberin.

The plant lipid polymers cutin and suberin play a critical role in many aspects of plant growth and development, and physiology. The mechanisms of cutin and suberin biosynthesis are relatively well understood thanks to just over two decades of work with primarily Arabidopsis (Arabidopsis thaliana) mutants. Recent advances in our understanding of cutin and suberin structure have arisen through the application of novel chemistries targeted at quantitative comprehension of intermolecular linkages, isolating intact suberins and cutins, and the application of advanced analytical techniques.

Altered Metabolism in Knockdown Lines of Two HXXXD/BAHD Acyltransferases During Wound Healing in Potato Tubers.

Suberin biosynthesis involves the coordinated regulation of both phenolic and aliphatic metabolisms. HXXXD/BAHD acyltransferases occupy a unique place in suberization, as they function to crosslink phenolic and aliphatic monomers during suberin assembly. To date, only one suberin-associated HXXXD/BAHD acyltransferase, StFHT, has been described in potatoes, whereas, in , at least two are implicated in suberin biosynthesis.

Integrative multi-omic analysis identifies genes associated with cuticular wax biogenesis in adult maize leaves.

Studying the genetic basis of leaf wax composition and its correlation with leaf cuticular conductance (gc) is crucial for improving crop productivity. The leaf cuticle, which comprises a cutin matrix and various waxes, functions as an extracellular hydrophobic layer, protecting against water loss upon stomatal closure. To address the limited understanding of genes associated with the natural variation of adult leaf cuticular waxes and their connection to gc, we conducted statistical genetic analyses using leaf transcriptomic, metabolomic, and physiological data sets collected from a maize (Zea mays L.

Compositional Analysis of Cutin in Maize Leaves.

The cuticle is a lipid barrier that covers the air-exposed surfaces of plants. It consists of waxes and cutin, a cell wall-attached lipid polyester of oxygenated fatty acids and glycerol. Unlike waxes, cutin is insoluble in organic solvents, and its composition is typically studied by chemical depolymerization followed by monomer analysis by gas chromatography (GC).

Kaempferol-3-rhamnoside overaccumulation in flavonoid 3'-hydroxylase tt7 mutants compromises seed coat outer integument differentiation and seed longevity.

Seeds slowly accumulate damage during storage, which ultimately results in germination failure. The seed coat protects the embryo from the external environment, and its composition is critical for seed longevity. Flavonols accumulate in the outer integument.

Rapid Detection of Carbapenemase and Extended-Spectrum β-Lactamase Producing Gram-Negative Bacteria Directly from Positive Blood Cultures Using a Novel Protocol.

Background: Early and adequate antibiotic treatment is the cornerstone of improving clinical outcomes in patients with bloodstream infections (BSI). Delays in appropriate antimicrobial therapy have catastrophic consequences for patients with BSI. Microbiological characterization of multi-drug resistant pathogens (MDRP) allows clinicians to provide appropriate treatments.

Chemical and Molecular Characterization of Wound-Induced Suberization in Poplar ( × ) Stem Bark.

Upon mechanical damage, plants produce wound responses to protect internal tissues from infections and desiccation. Suberin, a heteropolymer found on the inner face of primary cell walls, is deposited in specific tissues under normal development, enhanced under abiotic stress conditions and synthesized by any tissue upon mechanical damage. Wound-healing suberization of tree bark has been investigated at the anatomical level but very little is known about the molecular mechanisms underlying this important stress response.

Integrating GWAS and TWAS to elucidate the genetic architecture of maize leaf cuticular conductance.

The cuticle, a hydrophobic layer of cutin and waxes synthesized by plant epidermal cells, is the major barrier to water loss when stomata are closed. Dissecting the genetic architecture of natural variation for maize (Zea mays L.) leaf cuticular conductance (gc) is important for identifying genes relevant to improving crop productivity in drought-prone environments.

Root Suberin Plays Important Roles in Reducing Water Loss and Sodium Uptake in .

Suberin is a cell-wall-associated hetero-polymer deposited in specific plant tissues. The precise role of its composition and lamellae structure in protecting plants against abiotic stresses is unclear. In , we tested the biochemical and physiological responses to water deficiency and NaCl treatment in mutants that are differentially affected in suberin composition and lamellae structure.

ESCRT components ISTL1 andLIP5 are required for tapetal function and pollen viability.

Pollen wall assembly is crucial for pollen development and plant fertility. The durable biopolymer sporopollenin and the constituents of the tryphine coat are delivered to developing pollen grains by the highly coordinated secretory activity of the surrounding tapetal cells. The role of membrane trafficking in this process, however, is largely unknown.

A seed coat-specific β-ketoacyl-CoA synthase, KCS12, is critical for preserving seed physical dormancy.

Physical dormancy in seeds exists widely in seed plants and plays a vital role in maintaining natural seed banks. The outermost cuticle of the seed coat forms a water-impermeable layer, which is critical for establishing seed physical dormancy. We previously set up the legume plant Medicago truncatula as an excellent model for studying seed physical dormancy, and our studies revealed that a class II KNOTTED-like homeobox, KNOX4, is a transcription factor critical for controlling hardseededness.

Extracellular lipids of Camelina sativa: Characterization of cutin and suberin reveals typical polyester monomers and unusual dicarboxylic fatty acids.

Camelina sativa is relatively drought tolerant and requires less fertilizer than other oilseed crops. Various lipid- and phenolic-based extracellular barriers of plants help to protect them against biotic and abiotic stresses. These barriers, which consist of solvent-insoluble polymeric frameworks and solvent-extractable waxes, include the cuticle of aerial plant surfaces and suberized cell walls found, for example, in periderms and seed coats.

Structure-function analysis of the maize bulliform cell cuticle and its potential role in dehydration and leaf rolling.

The hydrophobic cuticle of plant shoots serves as an important interaction interface with the environment. It consists of the lipid polymer cutin, embedded with and covered by waxes, and provides protection against stresses including desiccation, UV radiation, and pathogen attack. Bulliform cells form in longitudinal strips on the adaxial leaf surface, and have been implicated in the leaf rolling response observed in drought-stressed grass leaves.

The FUSED LEAVES1-ADHERENT1 regulatory module is required for maize cuticle development and organ separation.

All aerial epidermal cells in land plants are covered by the cuticle, an extracellular hydrophobic layer that provides protection against abiotic and biotic stresses and prevents organ fusion during development. Genetic and morphological analysis of the classic maize adherent1 (ad1) mutant was combined with genome-wide binding analysis of the maize MYB transcription factor FUSED LEAVES1 (FDL1), coupled with transcriptional profiling of fdl1 mutants. We show that AD1 encodes an epidermally-expressed 3-KETOACYL-CoA SYNTHASE (KCS) belonging to a functionally uncharacterized clade of KCS enzymes involved in cuticular wax biosynthesis.

A maize LIPID TRANSFER PROTEIN may bridge the gap between PHYTOCHROME-mediated light signaling and cuticle biosynthesis.

Plant epidermal cuticles are composed of hydrophobic lipids that provide a barrier to non-stomatal water loss, and arose in land plants as an adaptation to the dry terrestrial environment. The expanding maize adult leaf displays a dynamic, proximodistal gradient of cuticle development, from the leaf base to the tip. Recently, our gene co-expression network analyses together with reverse genetic analyses suggested a previously undescribed function for PHYTOCHROME-mediated light signaling during cuticular wax deposition.

Transcriptomic network analyses shed light on the regulation of cuticle development in maize leaves.

Plant cuticles are composed of wax and cutin and evolved in the land plants as a hydrophobic boundary that reduces water loss from the plant epidermis. The expanding maize adult leaf displays a dynamic, proximodistal gradient of cuticle development, from the leaf base to the tip. Laser microdissection RNA Sequencing (LM-RNAseq) was performed along this proximodistal gradient, and complementary network analyses identified potential regulators of cuticle biosynthesis and deposition.

Genome-Wide Association Study for Maize Leaf Cuticular Conductance Identifies Candidate Genes Involved in the Regulation of Cuticle Development.

The cuticle, a hydrophobic layer of cutin and waxes synthesized by plant epidermal cells, is the major barrier to water loss when stomata are closed at night and under water-limited conditions. Elucidating the genetic architecture of natural variation for leaf cuticular conductance () is important for identifying genes relevant to improving crop productivity in drought-prone environments. To this end, we conducted a genome-wide association study of of adult leaves in a maize inbred association panel that was evaluated in four environments (Maricopa, AZ, and San Diego, CA, in 2016 and 2017).

PRX2 and PRX25, peroxidases regulated by COG1, are involved in seed longevity in Arabidopsis.

Permeability is a crucial trait that affects seed longevity and is regulated by different polymers including proanthocyanidins, suberin, cutin and lignin located in the seed coat. By testing mutants in suberin transport and biosynthesis, we demonstrate the importance of this biopolymer to cope with seed deterioration. Transcriptomic analysis of cog1-2D, a gain-of-function mutant with increased seed longevity, revealed the upregulation of several peroxidase genes.

Constructing functional cuticles: analysis of relationships between cuticle lipid composition, ultrastructure and water barrier function in developing adult maize leaves.

Background And Aims: Prior work has examined cuticle function, composition and ultrastructure in many plant species, but much remains to be learned about how these features are related. This study aims to elucidate relationships between these features via analysis of cuticle development in adult maize (Zea mays L.) leaves, while also providing the most comprehensive investigation to date of the composition and ultrastructure of adult leaf cuticles in this important crop plant.

Functional Overlap of Long-Chain Acyl-CoA Synthetases in Arabidopsis.

Long-chain acyl-CoA synthetases (LACSs) play diverse and essential roles in lipid metabolism. The genomes of model eukaryotic organisms encode multiple LACS genes, and the substrate specificities of LACS homologs often overlap substantially. Homologous LACSs tend to differ in their expression patterns, localizations, and, by extension, the metabolic pathways to which they contribute.

Segmentally homologous neurons acquire two different terminal neuropeptidergic fates in the Drosophila nervous system.

In this study, we identify the means by which segmentally homologous neurons acquire different neuropeptide fates in Drosophila. Ventral abdominal (Va)-neurons in the A1 segment of the ventral nerve cord express DH31 and AstA neuropeptides (neuropeptidergic fate I) by virtue of Ubx activity, whereas the A2-A4 Va-neurons express the Capa neuropeptide (neuropeptidergic fate II) under the influence of abdA. These different fates are attained through segment-specific programs of neural subtype specification undergone by segmentally homologous neurons.

Reconstructing the suberin pathway in poplar by chemical and transcriptomic analysis of bark tissues.

The tree bark periderm confers the first line of protection against pathogen invasion and abiotic stresses. The phellogen (cork cambium) externally produces cork (phellem) cells that are dead at maturity; while metabolically active, these tissues synthesize cell walls, as well as cell wall modifications, namely suberin and waxes. Suberin is a heteropolymer with aliphatic and aromatic domains, composed of acylglycerols, cross-linked polyphenolics and solvent-extractable waxes.