scispace - formally typeset
Search or ask a question
Journal ArticleDOI

Non-protein amino acids: plant, soil and ecosystem interactions

01 May 2011-Plant and Soil (Springer Netherlands)-Vol. 342, Iss: 1, pp 31-48
TL;DR: This review attempts to appraise the literature related to non-protein amino acids, both in terms of their metabolism, plant–soil interactions and at the level of the ecosystem, where they are seen as significant drivers of structure and function.
Abstract: Non-protein amino acids are a significant store of organic nitrogen in many ecosystems, but there is a lack of knowledge relating to them. Research has indicated that they play important roles as metabolites, as allelopthic chemicals, in nutrient acquisition, in signalling and in stress response. They are also thought to be responsible for significant medical issues in both invertebrate and vertebrate animals. This review attempts to appraise the literature related to non-protein amino acids, both in terms of their metabolism, plant–soil interactions and at the level of the ecosystem, where they are seen as significant drivers of structure and function. Finally, important areas for future research are discussed.
Citations
More filters
Journal ArticleDOI
TL;DR: The legal and regulatory status of biostimulants are described, with a focus on the EU and the US, and the drivers, opportunities and challenges of their market development are outlined.

1,340 citations

Journal ArticleDOI
TL;DR: There is growing scientific evidence supporting the use of biostimulants as agricultural inputs on diverse plant species, such as increased root growth, enhanced nutrient uptake, and stress tolerance.
Abstract: Plant biostimulants are diverse substances and microorganisms used to enhance plant growth. The global market for biostimulants is projected to increase 12 % per year and reach over $2,200 million by 2018. Despite the growing use of biostimulants in agriculture, many in the scientific community consider biostimulants to be lacking peer-reviewed scientific evaluation. This article describes the emerging definitions of biostimulants and reviews the literature on five categories of biostimulants: i. microbial inoculants, ii. humic acids, iii. fulvic acids, iv. protein hydrolysates and amino acids, and v. seaweed extracts. The large number of publications cited for each category of biostimulants demonstrates that there is growing scientific evidence supporting the use of biostimulants as agricultural inputs on diverse plant species. The cited literature also reveals some commonalities in plant responses to different biostimulants, such as increased root growth, enhanced nutrient uptake, and stress tolerance.

1,305 citations


Cites background from "Non-protein amino acids: plant, soi..."

  • ...These include the twenty structural amino acids involved in the synthesis of proteins as well as non-protein amino acids which are found abundantly in some plant species (Vranova et al. 2011)....

    [...]

  • ...There is considerable evidence that exogenous application of a number of structural and non-protein amino acids, including glutamate, histidine, proline, and glycine betaine can provide protection from environmental stresses or are active in metabolic signalling (Sharma and Dietz 2006; Forde and Lea 2007; Vranova et al. 2011; Liang et al. 2013)....

    [...]

  • ...…of a number of structural and non-protein amino acids, including glutamate, histidine, proline, and glycine betaine can provide protection from environmental stresses or are active in metabolic signalling (Sharma and Dietz 2006; Forde and Lea 2007; Vranova et al. 2011; Liang et al. 2013)....

    [...]

  • ...Several non-protein amino acids have also been shown to have roles in plant defense which is outside the scope of this review (see Huang et al. 2011; Vranova et al. 2011)....

    [...]

Journal ArticleDOI
TL;DR: This review has documented the recent advancement illustrating the harmful effects of ROS, antioxidant defense system involved in ROS detoxification under different abiotic stresses, and molecular cross-talk with other important signal molecules such as reactive nitrogen, sulfur, and carbonyl species.
Abstract: Global climate change and associated adverse abiotic stress conditions, such as drought, salinity, heavy metals, waterlogging, extreme temperatures, oxygen deprivation, etc., greatly influence plant growth and development, ultimately affecting crop yield and quality, as well as agricultural sustainability in general. Plant cells produce oxygen radicals and their derivatives, so-called reactive oxygen species (ROS), during various processes associated with abiotic stress. Moreover, the generation of ROS is a fundamental process in higher plants and employs to transmit cellular signaling information in response to the changing environmental conditions. One of the most crucial consequences of abiotic stress is the disturbance of the equilibrium between the generation of ROS and antioxidant defense systems triggering the excessive accumulation of ROS and inducing oxidative stress in plants. Notably, the equilibrium between the detoxification and generation of ROS is maintained by both enzymatic and nonenzymatic antioxidant defense systems under harsh environmental stresses. Although this field of research has attracted massive interest, it largely remains unexplored, and our understanding of ROS signaling remains poorly understood. In this review, we have documented the recent advancement illustrating the harmful effects of ROS, antioxidant defense system involved in ROS detoxification under different abiotic stresses, and molecular cross-talk with other important signal molecules such as reactive nitrogen, sulfur, and carbonyl species. In addition, state-of-the-art molecular approaches of ROS-mediated improvement in plant antioxidant defense during the acclimation process against abiotic stresses have also been discussed.

1,028 citations


Cites background from "Non-protein amino acids: plant, soi..."

  • ...Furthermore, nonprotein amino acids (gamma-aminobutyric acid, ornithine, and citrulline) are also considered as effective nonenzymatic antioxidant [155]....

    [...]

Book ChapterDOI
TL;DR: The positive effects of biostimulant application on plant nutrient uptake, and the underlying mechanisms, which include positive changes in soil structure or nutrient solubility, root morphology, plant physiology, and symbiotic relationships, will be discussed.
Abstract: Fertilizer use in modern agriculture is highly inefficient; much of the applied fertilizer is released into the environment, causing environmental degradation. One way in which fertilizer use can be reduced without damaging plant nutrition is to enhance crop uptake of nutrients through the use of biostimulants. A broad definition of plant biostimulants, including substances sometimes categorized as biofertilizers or biopesticides, is used throughout this review: “Plant biostimulants are substances or materials, with the exception of nutrients and pesticides, which, when applied to plants, seeds, or growing substrates in specific formulations, have the capacity to modify physiological processes in plants in a way that provides potential benefits to growth, development, or stress response.” This definition includes a variety of substances, four of which will be reviewed in this article: seaweed extract, humic substances, amino acids, and plant-growth-promoting bacteria. We will concentrate on the positive effects of biostimulant application on plant nutrient uptake, and the underlying mechanisms, which include positive changes in soil structure or nutrient solubility, root morphology, plant physiology, and symbiotic relationships, will be discussed. Recommendations for future research directions include finding the most promising substances, isolating the active ingredients and clearly demonstrating the mechanisms by which they affect nutrient uptake. The beneficial effects and mechanisms must be consistently demonstrated in greenhouse and field experiments.

262 citations


Cites background from "Non-protein amino acids: plant, soi..."

  • ...stresses, signaling, N storage, and chelation of metals as phytosiderophores (Vranova et al., 2011)....

    [...]

  • ...There are only 20 AA involved in protein building, but there are 250 more that are known to have diverse functions in plants, including protection from biotic and abiotic stresses, signaling, N storage, and chelation of metals as phytosiderophores (Vranova et al., 2011)....

    [...]

Journal ArticleDOI
TL;DR: Amino acids are shown to alter key phenotypes related to plant root growth and microbial colonization, symbiotic interactions, and pathogenesis in the rhizosphere, and can undergo rapid cellular flux.
Abstract: Often referred to as the "building blocks of proteins", the 20 canonical proteinogenic amino acids are ubiquitous in biological systems as the functional units in proteins. Sometimes overlooked are their varying additional roles that include serving as metabolic intermediaries, playing structural roles in bioactive natural products, acting as cosubstrates in enzymatic transformations, and as key regulators of cellular physiology. Amino acids can also serve as biological sources of both carbon and nitrogen and are found in the rhizosphere as a result of lysis or cellular efflux from plants and microbes and proteolysis of existing peptides. While both plants and microbes apparently prefer to take up nitrogen in its inorganic form, their ability to take up and use amino acids may confer a selective advantage in certain environments where organic nitrogen is abundant. Further, certain amino acids (e.g., glutamate and proline) and their betaines (e.g., glycine betaine) serve as compatible solutes necessary for osmoregulation in plants and microbes and can undergo rapid cellular flux. This ability is of particular importance in an ecological niche such as the rhizosphere, which is prone to significant variations in solute concentrations. Amino acids are also shown to alter key phenotypes related to plant root growth and microbial colonization, symbiotic interactions, and pathogenesis in the rhizosphere. This review will focus on the sources, transport mechanisms, and potential roles of the 20 canonical proteinogenic amino acids in the rhizosphere.

249 citations

References
More filters
Journal ArticleDOI
TL;DR: Of the compatible solutes tested, sorbitol, mannitol, myo-inositol and proline were effective hydroxyl radical scavengers and Glycinebetaine was ineffective.

1,969 citations


"Non-protein amino acids: plant, soi..." refers background in this paper

  • ...…1990; Ishimoto and Tanimura 2004 2-amino-5(carbamoylamino)p entanoic acid Citrulline Compatible solute (protective role), Nstorage, detoxification Smirnoff and Cumbes 1989; Hare et al. 1998; Akashi et al. 2001; Yokota et al. 2002; Rontein et al. 2002, Catoni et al. 2003; Akashi et al. 2008…...

    [...]

Journal ArticleDOI
TL;DR: Three classes of pigments act as visible signals to attract insects, birds and animals for pollination and seed dispersal, and protect plants from damage caused by UV and visible light.
Abstract: Plant compounds that are perceived by humans to have color are generally referred to as 'pigments'. Their varied structures and colors have long fascinated chemists and biologists, who have examined their chemical and physical properties, their mode of synthesis, and their physiological and ecological roles. Plant pigments also have a long history of use by humans. The major classes of plant pigments, with the exception of the chlorophylls, are reviewed here. Anthocyanins, a class of flavonoids derived ultimately from phenylalanine, are water-soluble, synthesized in the cytosol, and localized in vacuoles. They provide a wide range of colors ranging from orange/red to violet/blue. In addition to various modifications to their structures, their specific color also depends on co-pigments, metal ions and pH. They are widely distributed in the plant kingdom. The lipid-soluble, yellow-to-red carotenoids, a subclass of terpenoids, are also distributed ubiquitously in plants. They are synthesized in chloroplasts and are essential to the integrity of the photosynthetic apparatus. Betalains, also conferring yellow-to-red colors, are nitrogen-containing water-soluble compounds derived from tyrosine that are found only in a limited number of plant lineages. In contrast to anthocyanins and carotenoids, the biosynthetic pathway of betalains is only partially understood. All three classes of pigments act as visible signals to attract insects, birds and animals for pollination and seed dispersal. They also protect plants from damage caused by UV and visible light.

1,615 citations


"Non-protein amino acids: plant, soi..." refers background in this paper

  • ...DOPA is synthetised from tyrosine by tyrosine hydroxylase (Tanaka et al. 2008) and may be converted by DOPA-dioxygenase to betamic acid, or DOPA polyphenol oxidase to cDOPA 5GT (Christinet et al....

    [...]

  • ...DOPA is synthetised from tyrosine by tyrosine hydroxylase (Tanaka et al. 2008) and may be converted by DOPA-dioxygenase to betamic acid, or DOPA polyphenol oxidase to cDOPA 5GT (Christinet et al. 2004; Tanaka et al. 2008)....

    [...]

  • ...2008) and may be converted by DOPA-dioxygenase to betamic acid, or DOPA polyphenol oxidase to cDOPA 5GT (Christinet et al. 2004; Tanaka et al. 2008)....

    [...]

Journal ArticleDOI
TL;DR: New work suggests that serotonin may regulate some processes, including platelet aggregation, by receptor-independent, transglutaminase-dependent covalent linkage to cellular proteins.
Abstract: Serotonin is perhaps best known as a neurotransmitter that modulates neural activity and a wide range of neuropsychological processes, and drugs that target serotonin receptors are used widely in psychiatry and neurology. However, most serotonin is found outside the central nervous system, and virtually all of the 15 serotonin receptors are expressed outside as well as within the brain. Serotonin regulates numerous biological processes including cardiovascular function, bowel motility, ejaculatory latency, and bladder control. Additionally, new work suggests that serotonin may regulate some processes, including platelet aggregation, by receptor-independent, transglutaminase-dependent covalent linkage to cellular proteins. We review this new “expanded serotonin biology” and discuss how drugs targeting specific serotonin receptors are beginning to help treat a wide range of diseases.

1,487 citations


"Non-protein amino acids: plant, soi..." refers background in this paper

  • ...In addition to this, serotonin concentrated in fruit may act upon the digestive tracts of animals to aid the passage of seeds through the intestine (Berger et al. 2009)....

    [...]

Journal ArticleDOI
TL;DR: This review focuses on compiling the information available on the regulation and mechanisms of root exudation processes, and provides some ideas related to the evolutionary role ofRoot exudates in shaping soil microbial communities.
Abstract: Root-secreted chemicals mediate multi-partite interactions in the rhizosphere, where plant roots continually respond to and alter their immediate environment. Increasing evidence suggests that root exudates initiate and modulate dialogue between roots and soil microbes. For example, root exudates serve as signals that initiate symbiosis with rhizobia and mycorrhizal fungi. In addition, root exudates maintain and support a highly specific diversity of microbes in the rhizosphere of a given particular plant species, thus suggesting a close evolutionary link. In this review, we focus mainly on compiling the information available on the regulation and mechanisms of root exudation processes, and provide some ideas related to the evolutionary role of root exudates in shaping soil microbial communities.

1,412 citations

Journal ArticleDOI
TL;DR: In re-assessing the functional significance of compatible solute accumulation, it is suggested that proline and glycine betaine synthesis may buffer cellular redox potential and contribute to stress-tolerant phenotypes observed.
Abstract: Many plants accumulate organic osmolytes in response to the imposition of environmental stresses that cause cellular dehydration. Although an adaptive role for these compounds in mediating osmotic adjustment and protecting subcellular structure has become a central dogma in stress physiology, the evidence in favour of this hypothesis is largely correlative. Transgenic plants engineered to accumulate proline, mannitol, fructans, trehalose, glycine betaine or ononitol exhibit marginal improvements in salt and/or drought tolerance. While these studies do not dismiss causative relationships between osmolyte levels and stress tolerance, the absolute osmolyte concentrations in these plants are unlikely to mediate osmotic adjustment. Metabolic benefits of osmolyte accumulation may augment the classically accepted roles of these compounds. In re-assessing the functional significance of compatible solute accumulation, it is suggested that proline and glycine betaine synthesis may buffer cellular redox potential. Disturbances in hexose sensing in transgenic plants engineered to produce trehalose, fructans or mannitol may be an important contributory factor to the stress-tolerant phenotypes observed. Associated effects on photoassimilate allocation between root and shoot tissues may also be involved. Whether or not osmolyte transport between subcellular compartments or different organs represents a bottleneck that limits stress tolerance at the whole-plant level is presently unclear. None the less, if osmolyte metabolism impinges on hexose or redox signalling, then it may be important in long-range signal transmission throughout the plant.

1,293 citations


"Non-protein amino acids: plant, soi..." refers background in this paper

  • ...…2004 2-amino-5(carbamoylamino)p entanoic acid Citrulline Compatible solute (protective role), Nstorage, detoxification Smirnoff and Cumbes 1989; Hare et al. 1998; Akashi et al. 2001; Yokota et al. 2002; Rontein et al. 2002, Catoni et al. 2003; Akashi et al. 2008…...

    [...]