Molecular insights into plant desiccation tolerance: transcriptomics, proteomics and targeted metabolite profiling in Craterostigma plantagineum.

The resurrection plant Craterostigma plantagineum possesses an extraordinary capacity to survive long-term desiccation. To enhance our understanding of this phenomenon, complementary transcriptome, soluble proteome and targeted metabolite profiling was carried out on leaves collected from different stages during a dehydration and rehydration cycle. A total of 7348 contigs, 611 proteins and 39 metabolites were differentially abundant across the different sampling points.

The function of glutaredoxin GRXS15 is required for lipoyl-dependent dehydrogenases in mitochondria.

Iron-sulfur (Fe-S) clusters are ubiquitous cofactors in all life and are used in a wide array of diverse biological processes, including electron transfer chains and several metabolic pathways. Biosynthesis machineries for Fe-S clusters exist in plastids, the cytosol, and mitochondria. A single monothiol glutaredoxin (GRX) is involved in Fe-S cluster assembly in mitochondria of yeast and mammals.

The Craterostigma plantagineum protein kinase CpWAK1 interacts with pectin and integrates different environmental signals in the cell wall.

The cell wall protein CpWAK1 interacts with pectin, participates in decoding cell wall signals, and induces different downstream responses. Cell wall-associated protein kinases (WAKs) are transmembrane receptor kinases. In the desiccation-tolerant resurrection plant Craterostigma plantagineum, CpWAK1 has been shown to be involved in stress responses and cell expansion by forming a complex with the C.

Phytol derived from chlorophyll hydrolysis in plants is metabolized via phytenal.

Phytol is the isoprenoid alcohol bound in ester linkage to chlorophyll, the most abundant photosynthetic pigment in plants. During leaf senescence, large amounts of phytol are released by chlorophyll degradation. However, the pathway of phytol catabolism in plants is unknown.

Fatty acid isoprenoid alcohol ester synthesis in fruits of the African Oil Palm (Elaeis guineensis).

The African Oil Palm (Elaeis guineensis; family Arecaceae) represents the most important oil crop for food and feed production and for biotechnological applications. Two types of oil can be extracted from palm fruits, the mesocarp oil which is rich in palmitic acid and in carotenoids (provitamin A) and tocochromanols (vitamin E), and the kernel oil with high amounts of lauric and myristic acid. We identified fatty acid phytyl esters (FAPEs) in the mesocarp and kernel tissues of mature fruits, mostly esterified with oleic acid and very long chain fatty acids.

Identification and characterization of CTP:phosphocholine cytidylyltransferase CpCCT1 in the resurrection plant Craterostigma plantagineum.

Phosphatidylcholine is a major phospholipid which is shown to be involved in stress adaptation. Phosphatidylcholine increased during dehydration in Craterostigma plantagineum, and therefore we characterized CTP:phosphocholine cytidylyltransferase (CpCCT1), a key regulatory enzyme for phosphatidylcholine synthesis in plants. The CpCCT1 gene from the resurrection plant C.

The dehydration- and ABA-inducible germin-like protein CpGLP1 from Craterostigma plantagineum has SOD activity and may contribute to cell wall integrity during desiccation.

CpGLP1 belongs to the large group of germin-like proteins and comprises a cell wall-localized protein which has superoxide dismutase activity and may contribute towards ROS metabolism and cell wall folding during desiccation. The plant cell wall is a dynamic matrix and its plasticity is essential for cell growth and processing of environmental signals to cope with stresses. A few so-called resurrection plants like Craterostigma plantagineum survive desiccation by implementing protection mechanisms.

Nitrate and ammonium differ in their impact on δC of plant metabolites and respired CO from tobacco leaves.

The carbon isotopic composition (δC) of foliage is often used as proxy for plant performance. However, the effect of vs. supply on δC of leaf metabolites and respired CO is largely unknown.

sp. nov., a pink-coloured organism isolated from cheese made of cow's milk.

A pink-coloured bacterium (strain KR32) was isolated from cheese and assigned to the ' group'. Members of the 'pink group' form a stable clade (100 % bootstrap value) and contain the species , and , which share ≥99.0 % 16S rRNA gene sequence similarity.

Palmitvaccenic Acid (Δ11--hexadecenoic acid) Is Synthesized by an OLE1-like Desaturase in the Arbuscular Mycorrhiza Fungus .

Arbuscular mycorrhiza (AM) fungi deliver mineral nutrients to the plant host in exchange for reduced carbon in the form of sugars and lipids. Colonization with AM fungi upregulates a specific host lipid synthesis pathway resulting in the production of fatty acids. Predominantly palmitic acid (16:0) and the unusual palmitvaccenic acid (16:1) accumulate in the fungus .

The Dynamic Responses of Cell Walls in Resurrection Plants During Dehydration and Rehydration.

Plant cell walls define the shape of the cells and provide mechanical support. They function as osmoregulators by controlling the transport of molecules between cells and provide transport pathways within the plant. These diverse functions require a well-defined and flexible organization of cell wall components, i.

Ectopic expression of Medicago truncatula homeodomain finger protein, MtPHD6, enhances drought tolerance in Arabidopsis.

Background: The plant homeodomain (PHD) finger is a CysHisCys-type zinc finger which promotes protein-protein interactions and binds to the cis-acting elements in the promoter regions of target genes. In Medicago truncatula, five PHD homologues with full-length sequence were identified. However, the detailed function of PHD genes was not fully addressed.

Craterostigma plantagineum cell wall composition is remodelled during desiccation and the glycine-rich protein CpGRP1 interacts with pectins through clustered arginines.

Craterostigma plantagineum belongs to the desiccation-tolerant angiosperm plants. Upon dehydration, leaves fold and the cells shrink which is reversed during rehydration. To understand this process changes in cell wall pectin composition, and the role of the apoplastic glycine-rich protein 1 (CpGRP1) were analysed.

Chloroplast Lipids and Their Biosynthesis.

Chloroplasts contain high amounts of monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) and low levels of the anionic lipids sulfoquinovosyldiacylglycerol (SQDG), phosphatidylglycerol (PG), and glucuronosyldiacylglycerol (GlcADG). The mostly extraplastidial lipid phosphatidylcholine is found only in the outer envelope. Chloroplasts are the major site for fatty acid synthesis.

Surface wax esters contribute to drought tolerance in Arabidopsis.

Waxes are components of the cuticle covering the aerial organs of plants. Accumulation of waxes has previously been associated with protection against water loss, therefore contributing to drought tolerance. However, not much information is known about the function of individual wax components during water deficit.

Seed traits are pleiotropically regulated by the flowering time gene PERPETUAL FLOWERING 1 (PEP1) in the perennial Arabis alpina.

The life cycles of plants are characterized by two major life history transitions-germination and the initiation of flowering-the timing of which are important determinants of fitness. Unlike annuals, which make the transition from the vegetative to reproductive phase only once, perennials iterate reproduction in successive years. The floral repressor PERPETUAL FLOWERING 1 (PEP1), an ortholog of FLOWERING LOCUS C, in the alpine perennial Arabis alpina ensures the continuation of vegetative growth after flowering and thereby restricts the duration of the flowering episode.

Phytol metabolism in plants.

Phytol, the prenyl side chain of chlorophyll, is derived from geranylgeraniol by reduction of three double bonds. Recent results demonstrated that the conversion of geranylgeraniol to phytol is linked to chlorophyll synthesis, which is catalyzed by protein complexes associated with the thylakoid membranes. One of these complexes contains light harvesting chlorophyll binding like proteins (LIL3), enzymes of chlorophyll synthesis (protoporphyrinogen oxidoreductase, POR; chlorophyll synthase, CHLG) and geranylgeranyl reductase (GGR).

Transcriptional and metabolic changes in the desiccation tolerant plant Craterostigma plantagineum during recurrent exposures to dehydration.

Multiple dehydration/rehydration treatments improve the adaptation of Craterostigma plantagineum to desiccation by accumulating stress-inducible transcripts, proteins and metabolites. These molecules serve as stress imprints or memory and can lead to increased stress tolerance. It has been reported that repeated exposure to dehydration may generate stronger reactions during a subsequent dehydration treatment in plants.

The ATAF1 transcription factor is a key regulator of aldehyde dehydrogenase 7B4 (ALDH7B4) gene expression in Arabidopsis thaliana.

ALDH7B4 expression contributes to abiotic stress tolerance. The NAC transcription factor ATAF1 is a main regulator of expression of the ALDH7B4 gene in Arabidopsis thaliana as shown by ATAF1 mutants. The aldehyde dehydrogenase 7B4 (ALDH7B4) protein has important roles in detoxification of excessive aldehydes, elimination of reactive oxygen species (ROS) and inhibition of lipid peroxidation when plants are exposed to abiotic stress.

Disruption of microbial community composition and identification of plant growth promoting microorganisms after exposure of soil to rapeseed-derived glucosinolates.

Land plants are engaged in intricate communities with soil bacteria and fungi indispensable for plant survival and growth. The plant-microbial interactions are largely governed by specific metabolites. We employed a combination of lipid-fingerprinting, enzyme activity assays, high-throughput DNA sequencing and isolation of cultivable microorganisms to uncover the dynamics of the bacterial and fungal community structures in the soil after exposure to isothiocyanates (ITC) obtained from rapeseed glucosinolates.

Sugar metabolism in the desiccation tolerant grass Oropetium thomaeum in response to environmental stresses.

Oropetium thomaeum is a desiccation tolerant grass and acquisition of desiccation tolerance is correlated with changes in carbohydrate metabolism. Here we address the question whether the changes in carbohydrate metabolism are specific to the dehydration process or whether other environmental factors such as high temperature, low temperature, hypoxia, salinity or exogenous ABA application trigger the same or different changes in the sugar metabolism. Fifteen different sugar metabolites were identified by GC/MS, including erythritol, arabinose, fructose, galactose, glucose, myo-inositol, sedoheptulose, sucrose, trehalose, galactinol, maltose, raffinose, manninotriose and stachyose.

Headgroup hydroxylation by OlsE occurs at the C4 position of ornithine lipid and is widespread in proteobacteria and bacteroidetes.

Amino acid-containing acyloxyacyl lipids are composed of a 3-hydroxy fatty acid amide-bound to the α-amino group of an amino acid. A second fatty acid is ester-linked to the 3-hydroxy group of the first fatty acid. Most commonly, ornithine is the headgroup of these lipids, but glycine, serineglycine, glutamine and lysine have also been described in bacteria.

Molecular responses to dehydration and desiccation in desiccation-tolerant angiosperm plants.

Due to the ability to tolerate extreme dehydration, desiccation-tolerant plants have been widely investigated to find potential approaches for improving water use efficiency or developing new crop varieties. The studies of desiccation-tolerant plants have identified sugar accumulation, specific protein synthesis, cell structure changes, and increased anti-oxidative reactions as part of the mechanisms of desiccation tolerance. However, plants respond differently according to the severity of water loss, and the process of water loss affects desiccation tolerance.