Publications by authors named "Sunita A Ramesh"

Plant-microbe interactions are critical to ecosystem functioning and impact soil legacies, where plants exert a lasting influence on the microbial and physicochemical conditions of the soils in which they grow. These soil legacies can affect subsequent plant growth and fitness. Specifically, biotic soil legacies can influence microbially associated plant fitness through the movement of soil microbiota in a two-step selection process: Microbes are recruited from bulk soil into the rhizosphere (the space around roots) and then into the endosphere (within plant roots).

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Soil microbiota can colonise plant roots through a two-step selection process, involving recruitment of microbiota first from bulk soil into plant rhizospheres, then into root endospheres. This process is poorly understood in all but a few model species (e.g.

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Soil microbiota underpin ecosystem functionality yet are rarely targeted during ecosystem restoration. Soil microbiota recovery following native plant revegetation can take years to decades, while the effectiveness of soil inoculation treatments on microbiomes remains poorly explored. Therefore, innovative restoration treatments that target soil microbiota represent an opportunity to accelerate restoration outcomes.

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Aquaporin (AQP) channels found in all domains of life are transmembrane proteins which mediate passive transport of water, glycerol, signaling molecules, metabolites, and charged solutes. Discovery of new classes of ion-conducting AQP channels has been slow, likely reflecting time- and labor-intensive methods required for traditional electrophysiology. Work here defines a sensitive mass-throughput system for detecting AQP ion channels, identified by rescue of cell growth in the K+-transport-defective yeast strain CY162 following genetic complementation with heterologously expressed cation-permeable channels, using the well characterized human AQP1 channel for proof of concept.

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Despite mounting evidence of their importance in human health and ecosystem functioning, the definition and measurement of 'healthy microbiomes' remain unclear. More advanced knowledge exists on health associations for compounds used or produced by microbes. Environmental microbiome exposures (especially via soils) also help shape, and may supplement, the functional capacity of human microbiomes.

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Human aquaporin 1 (hAQP1) forms homotetrameric channels that facilitate fluxes of water and small solutes across cell membranes. In addition to water channel activity, hAQP1 displays non-selective monovalent cation-channel activity gated by intracellular cyclic GMP. Dual water and ion-channel activity of hAQP1, thought to regulate cell shape and volume, could offer a target for novel therapeutics relevant to controlling cancer cell invasiveness.

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Article Synopsis
  • The study focuses on reducing the movement of glioblastoma multiforme (GBM) cells, a highly aggressive brain cancer, using pharmacological inhibitors targeting ion and water channels.
  • Researchers tested various compounds, finding that they significantly decreased the invasiveness of specific GBM cell lines by 20-80% without harming the cells.
  • Two additional compounds, xanthurenic acid and caelestine C, were identified as effective at lower concentrations to block cell invasion in both GBM types, indicating potential for new treatment strategies.*
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Soil micronutrient availability, including zinc (Zn), is a limiting factor for crop yield. Arbuscular mycorrhizal (AM) fungi can improve host plant growth and nutrition through the mycorrhizal pathway of nutrient uptake. Although the physiology of Zn uptake through the mycorrhizal pathway is well established, the identity of the related molecular components are unknown.

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Plant-derived pharmacological agents have been used extensively to dissect the structure-function relationships of mammalian GABA receptors and ion channels. Picrotoxin is a non-competitive antagonist of mammalian GABA receptors. Here, we report that picrotoxin inhibits the anion (malate) efflux mediated by wheat () ALMT1 but has no effect on GABA transport.

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Article Synopsis
  • Aquaporins (AQPs) are specialized proteins that allow water and certain solutes to pass through cell membranes, with their ion-conducting properties first identified in AQP0 from bovine lenses.
  • Ongoing research focuses on the specific amino acids dictating solute permeability and the role of structural features like charged and hydrophobic residue rings, as well as how lipid environments influence AQP performance.
  • These AQPs are implicated in various biological functions, such as cell movement, pH regulation, and nutrient uptake, and advancements in computational tools and high-throughput assays may lead to groundbreaking discoveries in AQP function and interaction.
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  • Legumes create a partnership with rhizobia bacteria that helps them utilize nitrogen from the atmosphere for growth, with this process occurring in root structures called nodules.
  • Nitrogen-fixing occurs in special organelle-like structures called symbiosomes within the nodules, where the bacteria rely on carbon supplied by the legume in the form of sucrose.
  • The movement and assimilation of metabolic byproducts like malate in nodules are complex and require further research to fully understand the transport mechanisms and potential regulatory roles of compounds like GABA.
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Comprising more than half of all brain tumors, glioblastoma multiforme (GBM) is a leading cause of brain cancer-related deaths worldwide. A major clinical challenge is presented by the capacity of glioma cells to rapidly infiltrate healthy brain parenchyma, allowing the cancer to escape control by localized surgical resections and radiotherapies, and promoting recurrence in other brain regions. We propose that therapies which target cellular motility pathways could be used to slow tumor dispersal, providing a longer time window for administration of frontline treatments needed to directly eradicate the primary tumors.

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The signaling role for γ-Aminobutyric acid (GABA) has been documented in animals for over seven decades. However, a signaling role for GABA in plants is just beginning to emerge with the discovery of putative GABA binding site/s and GABA regulation of anion channels. In this review, we explore the role of GABA in plant growth and development under abiotic stress, its interactions with other signaling molecules and the probability that there are other anion channels with important roles in stress tolerance that are gated by GABA.

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Article Synopsis
  • TaALMT1 in wheat helps with aluminum tolerance at low pH and is activated in alkaline conditions, allowing the plant to adapt to different soil pH environments.
  • The wheat lines ET8 (Al-tolerant) and ES8 (Al-sensitive) showed that ET8 had better root growth and exuded more malate and GABA in high pH conditions.
  • Experiments showed that TaALMT1 not only helps acidify alkaline soils through malate and GABA exudation but also indicates a complex relationship with GABA synthesis and transport regulation.
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Hydraulics of plants that have different strategies of stomatal regulation under water stress are relatively poorly understood. We explore how root and shoot hydraulics, stomatal conductance ( ), leaf and root aquaporin (AQP) expression, and abscisic acid (ABA) concentration in leaf xylem sap ([ABA]) may be coordinated under mild water stress and exogenous ABA applications in two L. cultivars traditionally classified as near-isohydric (Grenache) and near-anisohydric (Syrah).

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Micronutrient deficiency is the cause of multiple diseases in developing countries. Staple crop biofortification is an efficient means to combat such deficiencies in the diets of local consumers. Biofortified lines of sweet potato (Ipomoea batata L.

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Plant aluminum-activated malate transporters (ALMTs) are currently classified as anion channels; they are also known to be regulated by diverse signals, leading to a range of physiological responses. Gamma-aminobutyric acid (GABA) regulation of anion flux through ALMT proteins requires a specific amino acid motif in ALMTs that shares similarity with a GABA binding site in mammalian GABA receptors. Here, we explore why TaALMT1 activation leads to a negative correlation between malate efflux and endogenous GABA concentrations ([GABA]) in both wheat () root tips and in heterologous expression systems.

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The role of γ-aminobutyric acid (GABA) as a signal in animals has been documented for over 60 years. In contrast, evidence that GABA is a signal in plants has only emerged in the last 15 years, and it was not until last year that a mechanism by which this could occur was identified-a plant 'GABA receptor' that inhibits anion passage through the aluminium-activated malate transporter family of proteins (ALMTs). ALMTs are multigenic, expressed in different organs and present on different membranes.

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The aquaporin AtPIP2;1 is an abundant plasma membrane intrinsic protein in Arabidopsis thaliana that is implicated in stomatal closure, and is highly expressed in plasma membranes of root epidermal cells. When expressed in Xenopus laevis oocytes, AtPIP2;1 increased water permeability and induced a non-selective cation conductance mainly associated with Na . A mutation in the water pore, G103W, prevented both the ionic conductance and water permeability of PIP2;1.

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The non-protein amino acid, gamma-aminobutyric acid (GABA) rapidly accumulates in plant tissues in response to biotic and abiotic stress, and regulates plant growth. Until now it was not known whether GABA exerts its effects in plants through the regulation of carbon metabolism or via an unidentified signalling pathway. Here, we demonstrate that anion flux through plant aluminium-activated malate transporter (ALMT) proteins is activated by anions and negatively regulated by GABA.

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Boron (B) toxicity is a significant limitation to cereal crop production in a number of regions worldwide. Here we describe the cloning of a gene from barley (Hordeum vulgare), underlying the chromosome 6H B toxicity tolerance quantitative trait locus. It is the second B toxicity tolerance gene identified in barley.

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A protocol for Agrobacterium-mediated transformation with either kanamycin or mannose selection was developed for leaf explants of the cultivar Prunus dulcis cv. Ne Plus Ultra. Regenerating shoots were selected on medium containing 15 muM kanamycin (negative selection), while in the positive selection strategy, shoots were selected on 2.

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Increasing the zinc content of cereal grains will be important for improving human nutrition. Improved plant zinc efficiency will lead to increased yields when available zinc is limiting plant growth. The aim of our work was to test how the over-expression of zinc transporters in cereals affects plant growth, seed mineral content, and zinc transport rates.

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A technique based on the reverse transcriptase-polymerase chain reaction (RT-PCR) has been developed to detect the presence of Prunus necrotic ringspot virus (PNRSV) and prune dwarf virus (PDV) simultaneously in almond. This paper presents the results of a 3-year study comparing both enzyme-linked immunosorbent assay (ELISA) and RT-PCR for the detection of PNRSV and PDV using 175 almond leaf samples. Multiplex RT-PCR was found to be more sensitive than ELISA, especially when followed by nested PCR for the detection of PDV.

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