Starch serves functions that range over a timescale of minutes to years, according the cell type from which it is derived. In guard cells, starch rapidly mobilized by synergistic action β-AMYLASE1 (BAM1) and α-AMYLASE3 (AMY3) promote stomatal opening. leaves, typically accumulates gradually during day degraded at night BAM3 support heterotrophic metabolism. During osmotic stress, in light stress-activated BAM1 release sugar sugar-derived osmolytes. Here, we report AMY3 also involved...

Abstract Fructose (Fru) is a major storage form of sugars found in vacuoles, yet the molecular regulation vacuolar Fru transport poorly studied. Although SWEET17 (for SUGARS WILL EVENTUALLY BE EXPORTED TRANSPORTERS17) has been characterized as exporter leaves, its expression leaves low. Here, RNA analysis and SWEET17-β-glucuronidase/-GREEN FLUORESCENT PROTEIN fusions expressed Arabidopsis (Arabidopsis thaliana) reveal that highly cortex roots localizes to tonoplast root cells. Expression was...

During photosynthesis of higher plants, absorbed light energy is converted into chemical that, in part, accumulated the form transitory starch within chloroplasts. In following night, mobilized to sustain heterotrophic metabolism plant. β-amylases are glucan hydrolases that cleave α-1,4-glycosidic bonds and release maltose units from non-reducing end polysaccharide chain. Arabidopsis, nocturnal degradation involves mainly β-amylase-3 (BAM3). A second β-amylase isoform, β-amylase-1 (BAM1),...

Abstract Starch is the major storage carbohydrate in plants. It comprised of glucans that form semicrystalline granules. Glucan phosphorylation a prerequisite for normal starch breakdown, but phosphoglucan metabolism not understood. A putative protein phosphatase encoded at Excess 4 (SEX4) locus Arabidopsis thaliana was recently shown to be required breakdown. Here, we show SEX4 vivo and define its role within degradation pathway. dephosphorylates both granule surface soluble phosphoglucans...

Here we show that related isoform AtPGP4 is expressed predominantly during early root development. loss‐of‐function plants reveal enhanced lateral initiation and hair lengths both known to be under the control of auxin. Further, atpgp4 altered sensitivities toward auxin transport inhibitor, NPA. Finally, mutant roots elevated free levels reduced capacities. These results together with yeast growth assays suggest a direct involvement in processes controlling

The rate, polarity, and symmetry of the flow plant hormone auxin are determined by polar cellular localization PIN-FORMED (PIN) efflux carriers. Flavonoids, a class secondary metabolites, have been suspected to modulate transport tropic responses. Nevertheless, identity specific flavonoid compounds involved their molecular function targets in vivo essentially unknown. Here we show that root elongation zone agravitropic pin2/eir1/wav6/agr1 has an altered pattern amount flavonol glycosides....

White lupins (Lupinus albus L.) respond to phosphate deficiency by producing special root structures called cluster roots. These roots secrete large amounts of carboxylates into the rhizosphere, mostly citrate and malate, which act as solubilizers enable plant grow in soils with sparingly available phosphate. The success efficiency such a P-acquisition strategy strongly depends on persistence stability soil, parameter that is influenced extent biodegradation through rhizosphere bacteria...

Abstract Following recent indirect evidence suggesting a role for ATP-binding cassette (ABC) transporters in root exudation of phytochemicals, we identified 25 ABC transporter genes highly expressed the cells most likely to be involved secretion processes. Of these genes, also selected six full-length and half-size in-depth molecular biochemical analyses. We compared exuded phytochemical profiles seven mutants those wild type. There were three nonpolar phytochemicals missing various type...

The immunophilin-like FKBP42 TWISTED DWARF1 (TWD1) has been shown to control plant development via the positive modulation of ABCB/P-glycoprotein (PGP)-mediated transport hormone auxin. TWD1 functionally interacts with two closely related proteins, ABCB1/PGP1 and ABCB19/PGP19/MDR1, both which exhibit ability bind be inhibited by synthetic auxin inhibitor N-1-naphylphtalamic acid (NPA). They are also flavonoid compounds, suspected modulators transport. mechanisms flavonoids NPA interfere...

Reproducible and efficient high-throughput phenotyping approaches, combined with advances in genome sequencing, are facilitating the discovery of genes affecting plant performance. Salinity tolerance is a desirable trait that can be achieved through breeding, where most have aimed at selecting for plants perform effective ion exclusion from shoots. To determine overall performance under salt stress, it helpful to investigate several traits collectively one experimental setup. Hence, we...

Abstract Starch contains phosphate covalently bound to the C6-position (70 80% of total phosphate) and C3-position (20 30%) glucosyl residues amylopectin fraction. In plants, transient phosphorylation starch renders granule surface more accessible glucan hydrolyzing enzymes is required for proper degradation. Phosphate also confers desired properties starch-derived pastes industrial applications. Arabidopsis thaliana, removal by phosphatase Excess4 (SEX4) essential breakdown. We identified a...

Starch in Arabidopsis (Arabidopsis thaliana) guard cells is rapidly degraded at the start of day by glucan hydrolases α-AMYLASE3 (AMY3) and β-AMYLASE1 (BAM1) to promote stomatal opening. This process activated via phototropin-mediated blue light signaling downstream plasma membrane H+-ATPase. It remains unknown how cell starch degradation integrates with light-regulated transport processes fine control opening kinetics. We report that H+, K+, Cl− across unaltered amy3 bam1 mutant, suggesting...

Article6 July 2020Open Access Transparent process Glucose uptake to guard cells via STP transporters provides carbon sources for stomatal opening and plant growth Sabrina Flütsch orcid.org/0000-0001-7020-6520 Institute of Integrative Biology, ETH Zürich, Switzerland Department Plant Microbial University Search more papers by this author Arianna Nigro Franco Conci Jiří Fajkus Photon Systems Instruments (PSI), Drasov, Czech Republic Matthias Thalmann orcid.org/0000-0002-6260-1448 Martin...

Abstract Stomatal opening requires the provision of energy in form ATP for proton pumping across guard cell (GC) plasma membrane and associated metabolic rearrangements. The source GCs is a matter ongoing debate that mainly fuelled by controversies around ability GC chloroplasts (GCCs) to perform photosynthesis. By imaging compartment-specific fluorescent NADPH sensor proteins Arabidopsis, we show photosynthesis limited mitochondria are main ATP. Unlike mature mesophyll (MC) chloroplasts,...

Acclimation of root growth is vital for plants to survive salt stress. Halophytes are great examples that thrive even under severe salinity, but their tolerance mechanisms, especially those mediated by responses, still largely unknown. We compared responses the halophyte Schrenkiella parvula with its glycophytic relative species Arabidopsis thaliana stress and performed transcriptomic analysis S. roots identify possible gene regulatory networks underlying physiological responses. do not...

Abstract Flavonoids are secondary metabolites known to modulate plant growth and development. A primary function of flavonols, a subgroup flavonoids, is thought be the modification auxin fluxes in plant. Flavonols cell glycosylated, repressor lrx1 (rol1) mutants Arabidopsis thaliana, affected rhamnose biosynthesis, have modified flavonol glycosylation profile. detailed analysis rol1-2 allele revealed hyponastic growth, aberrant pavement stomatal morphology cotyledons, defective trichome...

α-Amylases are glucan hydrolases that cleave α-1,4-glucosidic bonds in starch. In vascular plants, α-amylases can be classified into three subfamilies. Arabidopsis has one member of each subfamily. Among them, only AtAMY3 is localized the chloroplast. We expressed and purified from Escherichia coli carried out a biochemical characterization protein to find factors regulate its activity. Recombinant was active toward both insoluble starch granules soluble substrates, with strong preference...

The accumulation of starch within photosynthetic tissues and dedicated storage organs has been characterized extensively in many species, a function buffering carbon availability or fueling later growth phases, respectively, proposed. However, developmentally regulated turnover heterotrophic other than is poorly characterized, its not well understood. Here, we report on the characterization during flower, early embryo, silique development Arabidopsis (Arabidopsis thaliana) using combined...

β-Amylases (BAMs) are a multigene family of glucan hydrolytic enzymes playing key role not only for plant biology but also many industrial applications, such as the malting process in brewing and distilling industries. BAMs have been extensively studied Arabidopsis thaliana where they show surprising level complexity terms specialization within different isoforms well regulatory functions played by at least three catalytically inactive members. Despite importance fact that multiple BAM...