A nucleoside signal generated by a fungal endophyte regulates host cell death and promotes root colonization.

The intracellular colonization of plant roots by the beneficial fungal endophyte Serendipita indica follows a biphasic strategy, including a host cell death phase that enables successful colonization of Arabidopsis thaliana roots. How host cell death is initiated and controlled is largely unknown. Here, we show that two fungal enzymes, the ecto-5'-nucleotidase SiE5NT and the nuclease SiNucA, act synergistically in the apoplast at the onset of cell death to produce deoxyadenosine (dAdo).

An evolutionarily conserved metabolite inhibits biofilm formation in Escherichia coli K-12.

Methylerythritol cyclodiphosphate (MEcPP) is an intermediate in the biosynthesis of isoprenoids in plant plastids and in bacteria, and acts as a stress signal in plants. Here, we show that MEcPP regulates biofilm formation in Escherichia coli K-12 MG1655. Increased MEcPP levels, triggered by genetic manipulation or oxidative stress, inhibit biofilm development and production of fimbriae.

Hordedane diterpenoid phytoalexins restrict Fusarium graminearum infection but enhance Bipolaris sorokiniana colonization of barley roots.

Plant immunity is a multilayered process that includes recognition of patterns or effectors from pathogens to elicit defense responses. These include the induction of a cocktail of defense metabolites that typically restrict pathogen virulence. Here, we investigate the interaction between barley roots and the fungal pathogens Bipolaris sorokiniana (Bs) and Fusarium graminearum (Fg) at the metabolite level.

Combinatorial biosynthesis in yeast leads to over 200 diterpenoids.

Diterpenoids form a diverse group of natural products, many of which are or could become pharmaceuticals or industrial chemicals. The modular character of diterpene biosynthesis and the promiscuity of the enzymes involved make combinatorial biosynthesis a promising approach to generate libraries of diverse diterpenoids. Here, we report on the combinatorial assembly in yeast of ten diterpene synthases producing (+)-copalyl diphosphate-derived backbones and four cytochrome P450 oxygenases (CYPs) in diverse combinations.

Auxin-dependent regulation of cell division rates governs root thermomorphogenesis.

Roots are highly plastic organs enabling plants to adapt to a changing below-ground environment. In addition to abiotic factors like nutrients or mechanical resistance, plant roots also respond to temperature variation. Below the heat stress threshold, Arabidopsis thaliana seedlings react to elevated temperature by promoting primary root growth, possibly to reach deeper soil regions with potentially better water saturation.

Dynamics of Reactive Carbonyl Species in Pea Root Nodules in Response to Polyethylene Glycol (PEG)-Induced Osmotic Stress.

Drought dramatically affects crop productivity worldwide. For legumes this effect is especially pronounced, as their symbiotic association with rhizobia is highly-sensitive to dehydration. This might be attributed to the oxidative stress, which ultimately accompanies plants' response to water deficit.

At4g29530 is a phosphoethanolamine phosphatase homologous to PECP1 with a role in flowering time regulation.

Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) are the most abundant phospholipids in membranes. The biosynthesis of phospholipids occurs mainly via the Kennedy pathway. Recent studies have shown that through this pathway, choline (Cho) moieties are synthesized through the methylation of phosphoethanolamine (PEtn) to phosphocholine (PCho) by phospho-base N-methyltransferase.

Does Protein Glycation Impact on the Drought-Related Changes in Metabolism and Nutritional Properties of Mature Pea ( L.) Seeds?

Protein glycation is usually referred to as an array of non-enzymatic post-translational modifications formed by reducing sugars and carbonyl products of their degradation. The resulting advanced glycation end products (AGEs) represent a heterogeneous group of covalent adducts, known for their pro-inflammatory effects in mammals, and impacting on pathogenesis of metabolic diseases and ageing. In plants, AGEs are the markers of tissue ageing and response to environmental stressors, the most prominent of which is drought.

The inconspicuous gatekeeper: endophytic Serendipita vermifera acts as extended plant protection barrier in the rhizosphere.

In nature, beneficial and pathogenic fungi often simultaneously colonise plants. Despite substantial efforts to understand the composition of natural plant-microbe communities, the mechanisms driving such multipartite interactions remain largely unknown. Here we address how the interaction between the beneficial root endophyte Serendipita vermifera and the pathogen Bipolaris sorokiniana affects fungal behaviour and determines barley host responses using a gnotobiotic soil-based split-root system.

Strigolactone Levels in Dicot Roots Are Determined by an Ancestral Symbiosis-Regulated Clade of the Gene Family.

Strigolactones (SLs) are apocarotenoid phytohormones synthesized from carotenoid precursors. They are produced most abundantly in roots for exudation into the rhizosphere to cope with mineral nutrient starvation through support of root symbionts. Abscisic acid (ABA) is another apocarotenoid phytohormone synthesized in roots, which is involved in responses to abiotic stress.

Pi starvation-dependent regulation of ethanolamine metabolism by phosphoethanolamine phosphatase PECP1 in Arabidopsis roots.

A universal plant response to phosphorus deprivation is the up-regulation of a diverse array of phosphatases. As reported recently, the AtPECP1 gene encodes a phosphatase with in vitro substrate specificity for phosphoethanolamine and phosphocholine. The putative substrates suggested that AtPECP1 is related to phospholipid metabolism; however, the biological function of AtPECP1 is as yet not understood.

Initiation of ER Body Formation and Indole Glucosinolate Metabolism by the Plastidial Retrograde Signaling Metabolite, MEcPP.

Plants have evolved tightly regulated signaling networks to respond and adapt to environmental perturbations, but the nature of the signaling hub(s) involved have remained an enigma. We have previously established that methylerythritol cyclodiphosphate (MEcPP), a precursor of plastidial isoprenoids and a stress-specific retrograde signaling metabolite, enables cellular readjustments for high-order adaptive functions. Here, we specifically show that MEcPP promotes two Brassicaceae-specific traits, namely endoplasmic reticulum (ER) body formation and induction of indole glucosinolate (IGs) metabolism selectively, via transcriptional regulation of key regulators NAI1 for ER body formation and MYB51/122 for IGs biosynthesis).

Multi-Omics of Tomato Glandular Trichomes Reveals Distinct Features of Central Carbon Metabolism Supporting High Productivity of Specialized Metabolites.

Glandular trichomes are metabolic cell factories with the capacity to produce large quantities of secondary metabolites. Little is known about the connection between central carbon metabolism and metabolic productivity for secondary metabolites in glandular trichomes. To address this gap in our knowledge, we performed comparative metabolomics, transcriptomics, proteomics, and C-labeling of type VI glandular trichomes and leaves from a cultivated ( LA4024) and a wild ( LA1777) tomato accession.

Integrated omics analyses of retrograde signaling mutant delineate interrelated stress-response strata.

To maintain homeostasis in the face of intrinsic and extrinsic insults, cells have evolved elaborate quality control networks to resolve damage at multiple levels. Interorganellar communication is a key requirement for this maintenance, however the underlying mechanisms of this communication have remained an enigma. Here we integrate the outcome of transcriptomic, proteomic, and metabolomics analyses of genotypes including ceh1, a mutant with constitutively elevated levels of both the stress-specific plastidial retrograde signaling metabolite methyl-erythritol cyclodiphosphate (MEcPP) and the defense hormone salicylic acid (SA), as well as the high MEcPP but SA deficient genotype ceh1/eds16, along with corresponding controls.

Early responses of mature Arabidopsis thaliana plants to reduced water potential in the agar-based polyethylene glycol infusion drought model.

Drought is one of the most important environmental stressors resulting in increasing losses of crop plant productivity all over the world. Therefore, development of new approaches to increase the stress tolerance of crop plants is strongly desired. This requires precise and adequate modeling of drought stress.

Osmotic stress is accompanied by protein glycation in Arabidopsis thaliana.

Among the environmental alterations accompanying oncoming climate changes, drought is the most important factor influencing crop plant productivity. In plants, water deficit ultimately results in the development of oxidative stress and accumulation of osmolytes (e.g.

Elucidation of the biosynthesis of carnosic acid and its reconstitution in yeast.

Rosemary extracts containing the phenolic diterpenes carnosic acid and its derivative carnosol are approved food additives used in an increasingly wide range of products to enhance shelf-life, thanks to their high anti-oxidant activity. We describe here the elucidation of the complete biosynthetic pathway of carnosic acid and its reconstitution in yeast cells. Cytochrome P450 oxygenases (CYP76AH22-24) from Rosmarinus officinalis and Salvia fruticosa already characterized as ferruginol synthases are also able to produce 11-hydroxyferruginol.

Discovering Regulated Metabolite Families in Untargeted Metabolomics Studies.

The identification of metabolites by mass spectrometry constitutes a major bottleneck which considerably limits the throughput of metabolomics studies in biomedical or plant research. Here, we present a novel approach to analyze metabolomics data from untargeted, data-independent LC-MS/MS measurements. By integrated analysis of MS(1) abundances and MS/MS spectra, the identification of regulated metabolite families is achieved.

Autofluorescence as a Signal to Sort Developing Glandular Trichomes by Flow Cytometry.

The industrial relevance of a number of metabolites produced in plant glandular trichomes (GTs) has spurred research on these specialized organs for a number of years. Most of the research, however, has focused on the elucidation of secondary metabolite pathways and comparatively little has been undertaken on the development and differentiation of GTs. One way to gain insight into these developmental processes is to generate stage-specific transcriptome and metabolome data.

A Snapshot of the Plant Glycated Proteome: STRUCTURAL, FUNCTIONAL, AND MECHANISTIC ASPECTS.

Glycation is the reaction of carbonyl compounds (reducing sugars and α-dicarbonyls) with amino acids, lipids, and proteins, yielding early and advanced glycation end products (AGEs). The AGEs can be formed via degradation of early glycation intermediates (glycoxidation) and by interaction with the products of monosaccharide autoxidation (autoxidative glycosylation). Although formation of these potentially deleterious compounds is well characterized in animal systems and thermally treated foods, only a little information about advanced glycation in plants is available.

Isoprenoid and metabolite profiling of plant trichomes.

Plant glandular trichomes are specialized secretory structures located on the surface of the aerial parts of plants with large biosynthetic capacity, often with terpenoids as output molecules. The collection of plant trichomes requires a method to separate trichomes from leaf epidermal tissues. For metabolite profiling, trichome tissue needs to be rapidly quenched in order to maintain the indigenous state of intracellular intermediates.

An UPLC-MS/MS method for highly sensitive high-throughput analysis of phytohormones in plant tissues.

Background: Phytohormones are the key metabolites participating in the regulation of multiple functions of plant organism. Among them, jasmonates, as well as abscisic and salicylic acids are responsible for triggering and modulating plant reactions targeted against pathogens and herbivores, as well as resistance to abiotic stress (drought, UV-irradiation and mechanical wounding). These factors induce dramatic changes in phytohormone biosynthesis and transport leading to rapid local and systemic stress responses.

Nitrogen as an indicator of mass transfer during in-situ gas sparging.

Aiming at the stimulation of intrinsic microbial activity, pulses of pure oxygen or pressurized air were recurrently injected into groundwater polluted with chlorobenzene. To achieve well-controlled conditions and intensive sampling, a large, vertical underground tank was filled with the local unconfined sandy aquifer material. In the course of two individual gas injections, one using pure oxygen and one using pressurized air, the mass transfer of individual gas species between trapped gas phase and groundwater was studied.