Sodium (Na+) homeostasis and salt tolerance of plants
TL;DR: There is greater understanding about how cellular transport systems functionally integrate to facilitate tissue and organismal Na + homeostasis, and notable in this process are HKT1 Na + transporters, which regulate Na + loading into the root xylem, limiting flux to and accumulation in the shoot.
About: This article is published in Environmental and Experimental Botany.The article was published on 2013-08-01. It has received 358 citations till now. The article focuses on the topics: Antiporter & Na+/K+-ATPase.
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TL;DR: This paper provides a comprehensive review of major research advances on biochemical, physiological, and molecular mechanisms regulating plant adaptation and tolerance to salinity stress.
Abstract: Salinity is a major abiotic stress limiting growth and productivity of plants in many areas of the world due to increasing use of poor quality of water for irrigation and soil salinization. Plant adaptation or tolerance to salinity stress involves complex physiological traits, metabolic pathways, and molecular or gene networks. A comprehensive understanding on how plants respond to salinity stress at different levels and an integrated approach of combining molecular tools with physiological and biochemical techniques are imperative for the development of salt-tolerant varieties of plants in salt-affected areas. Recent research has identified various adaptive responses to salinity stress at molecular, cellular, metabolic, and physiological levels, although mechanisms underlying salinity tolerance are far from being completely understood. This paper provides a comprehensive review of major research advances on biochemical, physiological, and molecular mechanisms regulating plant adaptation and tolerance to salinity stress.
1,455 citations
TL;DR: An effective new paradigm is the targeted identification of specific genetic determinants of stress adaptation that have evolved in nature and their precise introgression into elite varieties.
Abstract: Crop yield reduction as a consequence of increasingly severe climatic events threatens global food security. Genetic loci that ensure productivity in challenging environments exist within the germplasm of crops, their wild relatives and species that are adapted to extreme environments. Selective breeding for the combination of beneficial loci in germplasm has improved yields in diverse environments throughout the history of agriculture. An effective new paradigm is the targeted identification of specific genetic determinants of stress adaptation that have evolved in nature and their precise introgression into elite varieties. These loci are often associated with distinct regulation or function, duplication and/or neofunctionalization of genes that maintain plant homeostasis.
727 citations
TL;DR: In this article, the authors discuss the evidence for Na+ and Cl− toxicity and the concept of tissue tolerance in relation to halophytes and suggest that halophyte tolerate cytoplasmic Na+/Cl− concentrations of 100-200mm.
490 citations
TL;DR: This review will introduce salt stress responses in plants and summarize the current knowledge about the most important ion transporters that facilitate intra- and intercellular K+ and Na+ homeostasis in these organisms.
Abstract: Soil salinity is a major abiotic stress that results in considerable crop yield losses worldwide. However, some plant genotypes show a high tolerance to soil salinity, as they manage to maintain a high K+/Na+ ratio in the cytosol, in contrast to salt stress susceptible genotypes. Although, different plant genotypes show different salt tolerance mechanisms, they all rely on the regulation and function of K+ and Na+ transporters and H+ pumps, which generate the driving force for K+ and Na+ transport. In this review we will introduce salt stress responses in plants and summarize the current knowledge about the most important ion transporters that facilitate intra- and intercellular K+ and Na+ homeostasis in these organisms. We will describe and discuss the regulation and function of the H+-ATPases, H+-PPases, SOS1, HKTs, and NHXs, including the specific tissues where they work and their response to salt stress.
366 citations
Cites background from "Sodium (Na+) homeostasis and salt t..."
...SOS2 phosphorylates CBL10 in a Ca2+ independent manner upon salt stress, and this phosphorylation stabilizes the SOS2-CBL10 complex association with the plasma membrane and increases SOS1 antiporter activity (Kim et al., 2007; Quan et al., 2007; Hasegawa, 2013)....
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...The SOS2-SOS3 complex associates with the Na+/H+ antiporter SOS1, phosphorylating its Cterminal auto-inhibitory domain, which becomes activated and thus pumps Na+ out of the cell (Pardo, 2010; Brini and Khaled, 2012; Hasegawa, 2013; Ji et al., 2013) (Figure 2)....
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...Such ABI2-SOS2 interaction may represent an integrating node between salt stress and ABA signaling (Ohta et al., 2003; Hasegawa, 2013)....
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...The process controlled by the Nax2 and Kna1 loci reduces net root xylem loading of Na+, while the Nax1 locus reduces Na+ accumulation in the leaf blade by restricting Na+ loading into root xylem and partitioning Na+ into the leaf sheath (James et al., 2006; Hasegawa, 2013)....
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TL;DR: It can be concluded that PGPB can be used as a cost effective and economical tool for salinity tolerance and growth promotion in plants.
334 citations
References
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TL;DR: The physiological and molecular mechanisms of tolerance to osmotic and ionic components of salinity stress are reviewed at the cellular, organ, and whole-plant level and the role of the HKT gene family in Na(+) exclusion from leaves is increasing.
Abstract: The physiological and molecular mechanisms of tolerance to osmotic and ionic components of salinity stress are reviewed at the cellular, organ, and whole-plant level. Plant growth responds to salinity in two phases: a rapid, osmotic phase that inhibits growth of young leaves, and a slower, ionic phase that accelerates senescence of mature leaves. Plant adaptations to salinity are of three distinct types: osmotic stress tolerance, Na + or Cl − exclusion, and the tolerance of tissue to accumulated Na + or Cl − . Our understanding of the role of the HKT gene family in Na + exclusion from leaves is increasing, as is the understanding of the molecular bases for many other transport processes at the cellular level. However, we have a limited molecular understanding of the overall control of Na + accumulation and of osmotic stress tolerance at the whole-plant level. Molecular genetics and functional genomics provide a new opportunity to synthesize molecular and physiological knowledge to improve the salinity tolerance of plants relevant to food production and environmental sustainability.
9,966 citations
TL;DR: The mechanisms of ROS generation and removal in plants during development and under biotic and abiotic stress conditions are described and the possible functions and mechanisms for ROS sensing and signaling in plants are compared with those in animals and yeast.
Abstract: Several reactive oxygen species (ROS) are continuously produced in plants as byproducts of aerobic metabolism. Depending on the nature of the ROS species, some are highly toxic and rapidly detoxified by various cellular enzymatic and nonenzymatic mechanisms. Whereas plants are surfeited with mechanisms to combat increased ROS levels during abiotic stress conditions, in other circumstances plants appear to purposefully generate ROS as signaling molecules to control various processes including pathogen defense, programmed cell death, and stomatal behavior. This review describes the mechanisms of ROS generation and removal in plants during development and under biotic and abiotic stress conditions. New insights into the complexity and roles that ROS play in plants have come from genetic analyses of ROS detoxifying and signaling mutants. Considering recent ROS-induced genome-wide expression analyses, the possible functions and mechanisms for ROS sensing and signaling in plants are compared with those in animals and yeast.
9,908 citations
TL;DR: Key steps of the signal transduction pathway that senses ROIs in plants have been identified and raise several intriguing questions about the relationships between ROI signaling, ROI stress and the production and scavenging ofROIs in the different cellular compartments.
9,395 citations
TL;DR: Salt and drought stress signal transduction consists of ionic and osmotic homeostasis signaling pathways, detoxification (i.e., damage control and repair) response pathways, and pathways for growth regulation.
Abstract: Salt and drought stress signal transduction consists of ionic and osmotic homeostasis signaling pathways, detoxification (i.e., damage control and repair) response pathways, and pathways for growth regulation. The ionic aspect of salt stress is signaled via the SOS pathway where a calcium-responsive SOS3-SOS2 protein kinase complex controls the expression and activity of ion transporters such as SOS1. Osmotic stress activates several protein kinases including mitogen-activated kinases, which may mediate osmotic homeostasis and/or detoxification responses. A number of phospholipid systems are activated by osmotic stress, generating a diverse array of messenger molecules, some of which may function upstream of the osmotic stress-activated protein kinases. Abscisic acid biosynthesis is regulated by osmotic stress at multiple steps. Both ABA-dependent and -independent osmotic stress signaling first modify constitutively expressed transcription factors, leading to the expression of early response transcriptional activators, which then activate downstream stress tolerance effector genes.
5,328 citations
01 Jun 2000
TL;DR: Evidence for plant stress signaling systems is summarized, some of which have components analogous to those that regulate osmotic stress responses of yeast, some that presumably function in intercellular coordination or regulation of effector genes in a cell-/tissue-specific context required for tolerance of plants.
Abstract: ▪ Abstract Plant responses to salinity stress are reviewed with emphasis on molecular mechanisms of signal transduction and on the physiological consequences of altered gene expression that affect biochemical reactions downstream of stress sensing. We make extensive use of comparisons with model organisms, halophytic plants, and yeast, which provide a paradigm for many responses to salinity exhibited by stress-sensitive plants. Among biochemical responses, we emphasize osmolyte biosynthesis and function, water flux control, and membrane transport of ions for maintenance and re-establishment of homeostasis. The advances in understanding the effectiveness of stress responses, and distinctions between pathology and adaptive advantage, are increasingly based on transgenic plant and mutant analyses, in particular the analysis of Arabidopsis mutants defective in elements of stress signal transduction pathways. We summarize evidence for plant stress signaling systems, some of which have components analogous to t...
4,596 citations