1
|
Ullah H, Jan T. Germination test, seedling growth, and physiochemical traits are used to screen okra varieties for salt tolerance. Heliyon 2024; 10:e34152. [PMID: 39071552 PMCID: PMC11277744 DOI: 10.1016/j.heliyon.2024.e34152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2024] [Revised: 06/25/2024] [Accepted: 07/04/2024] [Indexed: 07/30/2024] Open
Abstract
Excess soil salinity is a major stress factor that inhibits plant growth, development, and production. Among the growth stages, seed germination is particularly susceptible to salt stress. Okra, a nutraceutical vegetable, has a low germination percentage. Literature has revealed genetic diversity in okra, which can be studied to develop salt-tolerant varieties. This study examined the salt tolerance of 13 okra varieties using germination tests and then tested five varieties in pot experiments with different NaCl levels (75, 100, and 125 mM NaCl). Results showed that salt levels affected all varieties, with differential variations in stress response. Salt stress reduced agronomic, and physiochemical traits in the studied varieties. In variety "MALAV-27", the highest salt concentration significantly reduced the shoot length (68.12 %), root length (65.11 %), shoot fresh weight (78.73 %), root fresh weight (68.32 %), shoot dry weight (75.60 %), and root dry weight (75.81 %), along with different physiochemical traits. Variety "NAYAB-F1" performed the best, and maintained the highest shoot length (57.12 %), root length (58.72 %), shoot fresh weight (68.26 %), and root fresh weight (58.34 %), shoot dry weight (69.23 %), root dry weight (62.50 %), and numerous physiochemical traits such as sugar (0.74 μg/g), proline (0.51 μmol/g), and chlorophyll 'a' (7.97 mg/g), chlorophyll 'b' (9.56 mg/g). The study recommended 'NAYAB-F1', 'Arka anamika', and 'Shehzadi' as salt-tolerant varieties suitable for selection in salt-tolerant okra breeding programs.
Collapse
Affiliation(s)
- Hayat Ullah
- Department of Botany, University of Malakand, Chakdara, Dir (L), Khyber Pakhtunkhwa, Pakistan
| | - Tour Jan
- Department of Botany, University of Malakand, Chakdara, Dir (L), Khyber Pakhtunkhwa, Pakistan
| |
Collapse
|
2
|
Lindberg S, Premkumar A. Ion Changes and Signaling under Salt Stress in Wheat and Other Important Crops. PLANTS (BASEL, SWITZERLAND) 2023; 13:46. [PMID: 38202354 PMCID: PMC10780558 DOI: 10.3390/plants13010046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 12/14/2023] [Accepted: 12/16/2023] [Indexed: 01/12/2024]
Abstract
High concentrations of sodium (Na+), chloride (Cl-), calcium (Ca2+), and sulphate (SO42-) are frequently found in saline soils. Crop plants cannot successfully develop and produce because salt stress impairs the uptake of Ca2+, potassium (K+), and water into plant cells. Different intracellular and extracellular ionic concentrations change with salinity, including those of Ca2+, K+, and protons. These cations serve as stress signaling molecules in addition to being essential for ionic homeostasis and nutrition. Maintaining an appropriate K+:Na+ ratio is one crucial plant mechanism for salt tolerance, which is a complicated trait. Another important mechanism is the ability for fast extrusion of Na+ from the cytosol. Ca2+ is established as a ubiquitous secondary messenger, which transmits various stress signals into metabolic alterations that cause adaptive responses. When plants are under stress, the cytosolic-free Ca2+ concentration can rise to 10 times or more from its resting level of 50-100 nanomolar. Reactive oxygen species (ROS) are linked to the Ca2+ alterations and are produced by stress. Depending on the type, frequency, and intensity of the stress, the cytosolic Ca2+ signals oscillate, are transient, or persist for a longer period and exhibit specific "signatures". Both the influx and efflux of Ca2+ affect the length and amplitude of the signal. According to several reports, under stress Ca2+ alterations can occur not only in the cytoplasm of the cell but also in the cell walls, nucleus, and other cell organelles and the Ca2+ waves propagate through the whole plant. Here, we will focus on how wheat and other important crops absorb Na+, K+, and Cl- when plants are under salt stress, as well as how Ca2+, K+, and pH cause intracellular signaling and homeostasis. Similar mechanisms in the model plant Arabidopsis will also be considered. Knowledge of these processes is important for understanding how plants react to salinity stress and for the development of tolerant crops.
Collapse
Affiliation(s)
- Sylvia Lindberg
- Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-114 18 Stockholm, Sweden
| | - Albert Premkumar
- Bharathiyar Group of Institutes, Guduvanchery 603202, Tamilnadu, India;
| |
Collapse
|
3
|
Zhu X, Huang H, Luo X, Wei Y, Du S, Yu J, Guo S, Chen K, Chen L. Condensed tannin accretions specifically distributed in mesophyll cells of non-salt secretor mangroves help in salt tolerance. PLANTA 2023; 258:100. [PMID: 37839056 DOI: 10.1007/s00425-023-04254-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 09/25/2023] [Indexed: 10/17/2023]
Abstract
MAIN CONCLUSION Auto-fluorescent condensed tannins specifically accumulated in mesophyll cells of non-salt secretor mangroves are involved in the compartmentation of Na+ and osmotic regulation, contributing to their salt tolerance. Salinity is a major abiotic stress affecting the distribution and growth of mangrove plants. The salt exclusion mechanism from salt secretor mangrove leaves is quite known; however, salt management strategies in non-salt secretor leaves remain unclear. In this study, we reported the auto-fluorescent inclusions (AFIs) specifically accumulated in mesophyll cells (MCs) of four non-salt secretor mangroves but absent in three salt secretors. The AFIs increased with the leaf development under natural condition, and applied NaCl concentrations applied in the lab. The AFIs in MCs were isolated and identified as condensed tannin accretions (CTAs) using the dye dimethyl-amino-cinnamaldehyde (DMACA), specific for condensed tannin (CT), both in situ leaf cross sections and in the purified AFIs. Fluorescence microscopy and transmission electron microscope (TEM) analysis indicated that the CTAs originated from the inflated chloroplasts. The CTAs had an obvious membrane and could induce changes in shape and fluorescence intensity in hypotonic and hypertonic NaCl solutions, suggesting CTAs might have osmotic regulation ability and play an important role in the osmotic regulation in MCs. The purified CTAs were labeled by the fluorescent sodium-binding benzofuran isophthalate acetoxymethyl ester (SBFI-AM), confirming they were involved in the compartmentation of excess Na+ in MCs. This study provided a new view on the salt resistance-associated strategies in mangroves.
Collapse
Affiliation(s)
- Xueyi Zhu
- Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen, 361102, China
| | - Hezi Huang
- Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen, 361102, China
| | - Xu Luo
- School of Life Sciences, Xiamen University, Xiamen, 361102, China
| | - Yuanhai Wei
- School of Life Sciences, Xiamen University, Xiamen, 361102, China
| | - Shuangling Du
- School of Life Sciences, Xiamen University, Xiamen, 361102, China
| | - Jiamin Yu
- School of Life Sciences, Xiamen University, Xiamen, 361102, China
| | - Shengyu Guo
- School of Life Sciences, Xiamen University, Xiamen, 361102, China
| | - Kaiyun Chen
- School of Life Sciences, Xiamen University, Xiamen, 361102, China
| | - Linjiao Chen
- School of Life Sciences, Xiamen University, Xiamen, 361102, China.
| |
Collapse
|
4
|
Bouzroud S, Henkrar F, Fahr M, Smouni A. Salt stress responses and alleviation strategies in legumes: a review of the current knowledge. 3 Biotech 2023; 13:287. [PMID: 37520340 PMCID: PMC10382465 DOI: 10.1007/s13205-023-03643-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 05/21/2023] [Indexed: 08/01/2023] Open
Abstract
Salinity is one of the most significant environmental factors limiting legumes development and productivity. Salt stress disturbs all developmental stages of legumes and affects their hormonal regulation, photosynthesis and biological nitrogen fixation, causing nutritional imbalance, plant growth inhibition and yield losses. At the molecular level, salt stress exposure involves large number of factors that are implicated in stress perception, transduction, and regulation of salt responsive genes' expression through the intervention of transcription factors. Along with the complex gene network, epigenetic regulation mediated by non-coding RNAs, and DNA methylation events are also involved in legumes' response to salinity. Different alleviation strategies can increase salt tolerance in legume plants. The most promising ones are Plant Growth Promoting Rhizobia, Arbuscular Mycorrhizal Fungi, seed and plant's priming. Genetic manipulation offers an effective approach for improving salt tolerance. In this review, we present a detailed overview of the adverse effect of salt stress on legumes and their molecular responses. We also provide an overview of various ameliorative strategies that have been implemented to mitigate/overcome the harmful effects of salt stress on legumes.
Collapse
Affiliation(s)
- Sarah Bouzroud
- Equipe de Microbiologie et Biologie Moléculaire, Centre de Biotechnologie Végétale et Microbienne Biodiversité et Environnement, Faculté des Sciences, Université Mohammed V de Rabat, 10000 Rabat, Morocco
| | - Fatima Henkrar
- Laboratoire de Biotechnologie et Physiologie Végétales, Centre de Biotechnologie Végétale et Microbienne Biodiversité et Environnement, Faculté des Sciences, Université Mohammed V de Rabat, 10000 Rabat, Morocco
- Laboratoire Mixte International Activité Minière Responsable “LMI-AMIR”, IRD/UM5R/INAU, 10000 Rabat, Morocco
| | - Mouna Fahr
- Laboratoire de Biotechnologie et Physiologie Végétales, Centre de Biotechnologie Végétale et Microbienne Biodiversité et Environnement, Faculté des Sciences, Université Mohammed V de Rabat, 10000 Rabat, Morocco
- Laboratoire Mixte International Activité Minière Responsable “LMI-AMIR”, IRD/UM5R/INAU, 10000 Rabat, Morocco
| | - Abdelaziz Smouni
- Laboratoire de Biotechnologie et Physiologie Végétales, Centre de Biotechnologie Végétale et Microbienne Biodiversité et Environnement, Faculté des Sciences, Université Mohammed V de Rabat, 10000 Rabat, Morocco
- Laboratoire Mixte International Activité Minière Responsable “LMI-AMIR”, IRD/UM5R/INAU, 10000 Rabat, Morocco
| |
Collapse
|
5
|
Khan HA, Sharma N, Siddique KH, Colmer TD, Sutton T, Baumann U. Comparative transcriptome analysis reveals molecular regulation of salt tolerance in two contrasting chickpea genotypes. FRONTIERS IN PLANT SCIENCE 2023; 14:1191457. [PMID: 37360702 PMCID: PMC10289292 DOI: 10.3389/fpls.2023.1191457] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 04/26/2023] [Indexed: 06/28/2023]
Abstract
Salinity is a major abiotic stress that causes substantial agricultural losses worldwide. Chickpea (Cicer arietinum L.) is an important legume crop but is salt-sensitive. Previous physiological and genetic studies revealed the contrasting response of two desi chickpea varieties, salt-sensitive Rupali and salt-tolerant Genesis836, to salt stress. To understand the complex molecular regulation of salt tolerance mechanisms in these two chickpea genotypes, we examined the leaf transcriptome repertoire of Rupali and Genesis836 in control and salt-stressed conditions. Using linear models, we identified categories of differentially expressed genes (DEGs) describing the genotypic differences: salt-responsive DEGs in Rupali (1,604) and Genesis836 (1,751) with 907 and 1,054 DEGs unique to Rupali and Genesis836, respectively, salt responsive DEGs (3,376), genotype-dependent DEGs (4,170), and genotype-dependent salt-responsive DEGs (122). Functional DEG annotation revealed that the salt treatment affected genes involved in ion transport, osmotic adjustment, photosynthesis, energy generation, stress and hormone signalling, and regulatory pathways. Our results showed that while Genesis836 and Rupali have similar primary salt response mechanisms (common salt-responsive DEGs), their contrasting salt response is attributed to the differential expression of genes primarily involved in ion transport and photosynthesis. Interestingly, variant calling between the two genotypes identified SNPs/InDels in 768 Genesis836 and 701 Rupali salt-responsive DEGs with 1,741 variants identified in Genesis836 and 1,449 variants identified in Rupali. In addition, the presence of premature stop codons was detected in 35 genes in Rupali. This study provides valuable insights into the molecular regulation underpinning the physiological basis of salt tolerance in two chickpea genotypes and offers potential candidate genes for the improvement of salt tolerance in chickpeas.
Collapse
Affiliation(s)
- Hammad Aziz Khan
- UWA School of Agriculture and Environment, The University of Western Australia, Perth, WA, Australia
- The UWA Institute of Agriculture, The University of Western Australia, Perth, WA, Australia
| | - Niharika Sharma
- NSW Department of Primary Industries, Orange Agricultural Institute, Orange, NSW, Australia
| | - Kadambot H.M. Siddique
- UWA School of Agriculture and Environment, The University of Western Australia, Perth, WA, Australia
- The UWA Institute of Agriculture, The University of Western Australia, Perth, WA, Australia
| | - Timothy David Colmer
- UWA School of Agriculture and Environment, The University of Western Australia, Perth, WA, Australia
- The UWA Institute of Agriculture, The University of Western Australia, Perth, WA, Australia
| | - Tim Sutton
- School of Agriculture, Food and Wine, University of Adelaide, Adelaide, SA, Australia
- Department of Primary Industries and Regions, South Australian Research and Development Institute (SARDI), Adelaide, SA, Australia
| | - Ute Baumann
- School of Agriculture, Food and Wine, University of Adelaide, Adelaide, SA, Australia
| |
Collapse
|
6
|
Morgan SH, Kader MA, Lindberg S. Cytosolic Sodium Influx in Mesophyll Protoplasts of Arabidopsis thaliana, wt, sos1:1 and nhx1 Differs and Induces Different Calcium Changes. PLANTS (BASEL, SWITZERLAND) 2022; 11:3439. [PMID: 36559553 PMCID: PMC9780823 DOI: 10.3390/plants11243439] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 11/28/2022] [Accepted: 12/07/2022] [Indexed: 06/17/2023]
Abstract
The sodium influx into the cytosol of mesophyll protoplasts from Arabidopsis thaliana cv. Columbia, wild type, was compared with the influx into sos1-1 and nhx1 genotypes, which lack the Na+/H+ antiporter in the plasma membrane and tonoplast, respectively. Changes in cytosolic sodium and calcium concentrations upon a 100 mM NaCl addition were detected by use of epifluorescence microscopy and the sodium-specific fluorescent dye SBFI, AM, and calcium sensitive Fura 2, AM, respectively. There was a smaller and mainly transient influx of Na+ in the cytosol of the wild type compared with the sos1-1 and nhx1 genotypes, in which the influx lasted for a longer time. Sodium chloride addition to the protoplasts' medium induced a significant increase in cytosolic calcium concentration in the wild type at 1.0 mM external calcium, and to a lesser extent in nhx1, however, it was negligible in the sos1-1 genotype. LiCl inhibited the cytosolic calcium elevation in the wild type. The results suggest that the salt-induced calcium elevation in the cytosol of mesophyll cells depends on an influx from both internal and external stores and occurs in the presence of an intact Na+/H+ antiporter at the plasma membrane. The Arabidopsis SOS1 more effectively regulates sodium homeostasis than NHX1.
Collapse
Affiliation(s)
- Sherif H. Morgan
- Plant Botany Department, Faculty of Agriculture, Cairo University, Cairo 12613, Egypt
| | - Md Abdul Kader
- Department of Agronomy, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh
| | - Sylvia Lindberg
- Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-106 91 Stockholm, Sweden
| |
Collapse
|
7
|
Wang J, Cai C, Geng P, Tan F, Yang Q, Wang R, Shen W. A New Discovery of Argon Functioning in Plants: Regulation of Salinity Tolerance. Antioxidants (Basel) 2022; 11:antiox11061168. [PMID: 35740064 PMCID: PMC9220380 DOI: 10.3390/antiox11061168] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 06/12/2022] [Accepted: 06/12/2022] [Indexed: 02/01/2023] Open
Abstract
Argon, a non-polar molecule, easily diffuses into deeper tissue and interacts with larger proteins, protein cavities, or even receptors. Some of the biological effects of argon, notably its activity as an antioxidant, have been revealed in animals. However, whether and how argon influences plant physiology remains elusive. Here, we provide the first report that argon can enable plants to cope with salinity toxicity. Considering the convenience of the application, argon gas was dissolved into water (argon-rich water (ARW)) to investigate the argon’s functioning in phenotypes of alfalfa seed germination and seedling growth upon salinity stress. The biochemical evidence showed that NaCl-decreased α/β-amylase activities were abolished by the application of ARW. The qPCR experiments confirmed that ARW increased NHX1 (Na+/H+ antiporter) transcript and decreased SKOR (responsible for root-to-shoot translocation of K+) mRNA abundance, the latter of which could be used to explain the lower net K+ efflux and higher K accumulation. Subsequent results using non-invasive micro-test technology showed that the argon-intensified net Na+ efflux and its reduced Na accumulation resulted in a lower Na+/K+ ratio. NaCl-triggered redox imbalance and oxidative stress were impaired by ARW, as confirmed by histochemical and confocal analyses, and increased antioxidant defense was also detected. Combined with the pot experiments in a greenhouse, the above results clearly demonstrated that argon can enable plants to cope with salinity toxicity via reestablishing ion and redox homeostasis. To our knowledge, this is the first report to address the function of argon in plant physiology, and together these findings might open a new window for the study of argon biology in plant kingdoms.
Collapse
Affiliation(s)
- Jun Wang
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; (J.W.); (C.C.); (P.G.); (F.T.); (Q.Y.)
| | - Chenxu Cai
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; (J.W.); (C.C.); (P.G.); (F.T.); (Q.Y.)
| | - Puze Geng
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; (J.W.); (C.C.); (P.G.); (F.T.); (Q.Y.)
| | - Feng Tan
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; (J.W.); (C.C.); (P.G.); (F.T.); (Q.Y.)
| | - Qing Yang
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; (J.W.); (C.C.); (P.G.); (F.T.); (Q.Y.)
| | - Ren Wang
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing 210014, China;
| | - Wenbiao Shen
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; (J.W.); (C.C.); (P.G.); (F.T.); (Q.Y.)
- Correspondence: ; Tel.: +86-025-84399032
| |
Collapse
|
8
|
Sagervanshi A, Geilfus CM, Kaiser H, Mühling KH. Alkali salt stress causes fast leaf apoplastic alkalinization together with shifts in ion and metabolite composition and transcription of key genes during the early adaptive response of Vicia faba L. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2022; 319:111253. [PMID: 35487662 DOI: 10.1016/j.plantsci.2022.111253] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 03/09/2022] [Accepted: 03/11/2022] [Indexed: 06/14/2023]
Abstract
The mechanisms by which plants respond to alkali salt stress are still obscure, and the relevance of alkaline pH under combined alkali salt stress. Early stress responses can indicate mechanisms leading to damage and plant resistance. The apoplast contains essential determinants for plant growth, specifically early apoplastic pH fluctuations are induced by many stressors and hypothesized to be involved in stress signalling. Hence, this study aims to identify fast responses specific to alkaline pH and alkali salt stress by exposing the root of hydroponically grown Vicia faba L. plants to 150 min of either 50 mM NaHCO3 (pH 9) treatment or alkaline pH 9 alone. Apoplastic pH was monitored in real-time by ratiometric fluorescence microscopy simultaneously with SWIR transmission-based measurements of leaf water content (LWC). Moreover, we examined the effect of these stresses on apoplastic, symplastic and xylem ion and metabolite composition together with transcriptions of certain stress-responsive genes. Physiological and transcriptional changes were observed in response to NaHCO3 but not to alkaline pH alone. NaHCO3 elicited a transient reduction in LWC, followed by a transient alkalinization of the apoplast and stomatal closure. Simultaneously, organic acids and sugars accumulated. Fast upregulation of stress-responsive genes showed the significance of gene regulation for early plant adaptation to alkali salt stress.
Collapse
Affiliation(s)
- Amit Sagervanshi
- Institute of Plant Nutrition and Soil Science, Kiel University, Kiel, Germany
| | - Christoph-Martin Geilfus
- Institute of Plant Nutrition and Soil Science, Kiel University, Kiel, Germany; Department of Soil Science and Plant Nutrition, Hochschule Geisenheim University, Germany
| | - Hartmut Kaiser
- Institute of Plant Nutrition and Soil Science, Kiel University, Kiel, Germany
| | - Karl H Mühling
- Institute of Plant Nutrition and Soil Science, Kiel University, Kiel, Germany.
| |
Collapse
|
9
|
Mishra M, Wungrampha S, Kumar G, Singla-Pareek SL, Pareek A. How do rice seedlings of landrace Pokkali survive in saline fields after transplantation? Physiology, biochemistry, and photosynthesis. PHOTOSYNTHESIS RESEARCH 2021; 150:117-135. [PMID: 32632535 DOI: 10.1007/s11120-020-00771-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 06/24/2020] [Indexed: 06/11/2023]
Abstract
Rice, one of the most important staple food crops in the world, is highly sensitive to soil salinity at the seedling stage. The ultimate yield of this crop is a function of the number of seedlings surviving after transplantation in saline water. Oryza sativa cv. IR64 is a high-yielding salinity-sensitive variety, while Pokkali is a landrace traditionally cultivated by the local farmers in the coastal regions in India. However, the machinery responsible for the seedling-stage tolerance in Pokkali is not understood. To bridge this gap, we subjected young seedlings of these contrasting genotypes to salinity and performed detailed investigations about their growth parameters, ion homeostasis, biochemical composition, and photosynthetic parameters after every 24 h of salinity for three days. Taken together, all the physiological and biochemical indicators, such as proline accumulation, K+/Na+ ratio, lipid peroxidation, and electrolyte leakage, clearly revealed significant differences between IR64 and Pokkali under salinity, establishing their contrasting nature at this stage. In response to salinity, the Fv/Fm ratio (maximum quantum efficiency of Photosystem II as inferred from Chl a fluorescence) and the energy conserved for the electron transport after the reduction of QA (the primary electron acceptor of PSII), to QA-, and reduction of the end electron acceptor molecules towards the PSI (Photosystem I) electron acceptor side was higher in Pokkali than IR64 plants. These observations reflect a direct contribution of photosynthesis towards seedling-stage salinity tolerance in rice. These findings will help to breed high-yielding crops for salinity prone agricultural lands.
Collapse
Affiliation(s)
- Manjari Mishra
- Stress Physiology and Molecular Biology Lab, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Silas Wungrampha
- Stress Physiology and Molecular Biology Lab, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Gautam Kumar
- Stress Physiology and Molecular Biology Lab, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Sneh Lata Singla-Pareek
- Plant Stress Biology, International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
| | - Ashwani Pareek
- Stress Physiology and Molecular Biology Lab, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
| |
Collapse
|
10
|
Ruwanpathirana GP, Plett DC, Williams RC, Davey CE, Johnston LA, Kronzucker HJ. Continuous monitoring of plant sodium transport dynamics using clinical PET. PLANT METHODS 2021; 17:8. [PMID: 33468197 PMCID: PMC7814562 DOI: 10.1186/s13007-021-00707-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 01/04/2021] [Indexed: 05/11/2023]
Abstract
BACKGROUND The absorption, translocation, accumulation and excretion of substances are fundamental processes in all organisms including plants, and have been successfully studied using radiotracers labelled with 11C, 13N, 14C and 22Na since 1939. Sodium is one of the most damaging ions to the growth and productivity of crops. Due to the significance of understanding sodium transport in plants, a significant number of studies have been carried out to examine sodium influx, compartmentation, and efflux using 22Na- or 24Na-labeled salts. Notably, however, most of these studies employed destructive methods, which has limited our understanding of sodium flux and distribution characteristics in real time, in live plants. Positron emission tomography (PET) has been used successfully in medical research and diagnosis for decades. Due to its ability to visualise and assess physiological and metabolic function, PET imaging has also begun to be employed in plant research. Here, we report the use of a clinical PET scanner with a 22Na tracer to examine 22Na-influx dynamics in barley plants (Hordeum vulgare L. spp. Vulgare-cultivar Bass) under variable nutrient levels, alterations in the day/night light cycle, and the presence of sodium channel inhibitors. RESULTS 3D dynamic PET images of whole plants show readily visible 22Na translocation from roots to shoots in each examined plant, with rates influenced by both nutrient status and channel inhibition. PET images show that plants cultivated in low-nutrient media transport more 22Na than plants cultivated in high-nutrient media, and that 22Na uptake is suppressed in the presence of a cation-channel inhibitor. A distinct diurnal pattern of 22Na influx was discernible in curves displaying rates of change of relative radioactivity. Plants were found to absorb more 22Na during the light period, and anticipate the change in the light/dark cycle by adjusting the sodium influx rate downward in the dark period, an effect not previously described experimentally. CONCLUSIONS We demonstrate the utility of clinical PET/CT scanners for real-time monitoring of the temporal dynamics of sodium transport in plants. The effects of nutrient deprivation and of ion channel inhibition on sodium influx into barley plants are shown in two proof-of-concept experiments, along with the first-ever 3D-imaging of the light and dark sodium uptake cycles in plants. This method carries significant potential for plant biology research and, in particular, in the context of genetic and treatment effects on sodium acquisition and toxicity in plants.
Collapse
Affiliation(s)
- Gihan P Ruwanpathirana
- Melbourne Brain Centre Imaging Unit, The University of Melbourne, Melbourne, VIC, Australia
- Department of Biomedical Engineering, The University of Melbourne, Melbourne, VIC, Australia
| | - Darren C Plett
- Australian Plant Phenomics Facility, The Plant Accelerator, School of Agriculture, Food & Wine, University of Adelaide, Urrbrae, SA, Australia
| | - Robert C Williams
- Melbourne Brain Centre Imaging Unit, The University of Melbourne, Melbourne, VIC, Australia
| | - Catherine E Davey
- Melbourne Brain Centre Imaging Unit, The University of Melbourne, Melbourne, VIC, Australia
- Department of Biomedical Engineering, The University of Melbourne, Melbourne, VIC, Australia
| | - Leigh A Johnston
- Melbourne Brain Centre Imaging Unit, The University of Melbourne, Melbourne, VIC, Australia.
- Department of Biomedical Engineering, The University of Melbourne, Melbourne, VIC, Australia.
| | - Herbert J Kronzucker
- Faculty of Veterinary and Agriculture Sciences, School of Agriculture and Food, The University of Melbourne, Melbourne, VIC, Australia
- Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| |
Collapse
|
11
|
Wang J, Nan N, Li N, Liu Y, Wang TJ, Hwang I, Liu B, Xu ZY. A DNA Methylation Reader-Chaperone Regulator-Transcription Factor Complex Activates OsHKT1;5 Expression during Salinity Stress. THE PLANT CELL 2020; 32:3535-3558. [PMID: 32938753 PMCID: PMC7610284 DOI: 10.1105/tpc.20.00301] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 08/31/2020] [Accepted: 09/13/2020] [Indexed: 05/20/2023]
Abstract
Irrigated lands are increasingly salinized, which adversely affects agricultural productivity. To respond to high sodium (Na+) concentrations, plants harbor multiple Na+ transport systems. Rice (Oryza sativa) HIGH-AFFINITY POTASSIUM (K+) TRANSPORTER1;5 (OsHKT1;5), a Na+-selective transporter, maintains K+/Na+ homeostasis under salt stress. However, the mechanism regulating OsHKT1;5 expression remains unknown. Here, we present evidence that a protein complex consisting of rice BCL-2-ASSOCIATED ATHANOGENE4 (OsBAG4), OsMYB106, and OsSUVH7 regulates OsHKT1;5 expression in response to salt stress. We isolated a salt stress-sensitive mutant, osbag4-1, that showed significantly reduced OsHKT1;5 expression and reduced K+ and elevated Na+ levels in shoots. Using comparative interactomics, we isolated two OsBAG4-interacting proteins, OsMYB106 (a MYB transcription factor) and OsSUVH7 (a DNA methylation reader), that were crucial for OsHKT1;5 expression. OsMYB106 and OsSUVH7 bound to the MYB binding cis-element (MYBE) and the miniature inverted-repeat transposable element (MITE) upstream of the MYBE, respectively, in the OsHKT1;5 promoter. OsBAG4 functioned as a bridge between OsSUVH7 and OsMYB106 to facilitate OsMYB106 binding to the consensus MYBE in the OsHKT1;5 promoter, thereby activating the OsHKT1;5 expression. Elimination of the MITE or knockout of OsMYB106 or OsSUVH7 decreased OsHKT1;5 expression and increased salt sensitivity. Our findings reveal a transcriptional complex, consisting of a DNA methylation reader, a chaperone regulator, and a transcription factor, that collaboratively regulate OsHKT1;5 expression during salinity stress.
Collapse
Affiliation(s)
- Jie Wang
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun 130024, People's Republic of China
| | - Nan Nan
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun 130024, People's Republic of China
| | - Ning Li
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun 130024, People's Republic of China
| | - Yutong Liu
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun 130024, People's Republic of China
| | - Tian-Jing Wang
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun 130024, People's Republic of China
| | - Inhwan Hwang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Bao Liu
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun 130024, People's Republic of China
| | - Zheng-Yi Xu
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun 130024, People's Republic of China
| |
Collapse
|
12
|
Myo T, Tian B, Zhang Q, Niu S, Liu Z, Shi Y, Cao G, Ling H, Wei F, Shi G. Ectopic overexpression of a cotton plastidial Na + transporter GhBASS5 impairs salt tolerance in Arabidopsis via increasing Na + loading and accumulation. PLANTA 2020; 252:41. [PMID: 32856159 DOI: 10.1007/s00425-020-03445-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Accepted: 08/18/2020] [Indexed: 05/11/2023]
Abstract
GhBASS5 is a member of the bile acid sodium symporter (BASS) gene family from cotton and a plastid-localized Na+ transporter that negatively regulates salt tolerance of plants. Soil salinization is a major constraint on global cotton production, and Na+ is the most dominant toxic ion in salinity stress. Hence, insights into the identities and properties of transporters that catalyze Na+ movement between different tissues and within the cell compartments are vital to understand the salt-tolerant mechanisms of plants. Here, we identified the GhBASS5 gene, a member of the bile acid sodium symporter (BASS) gene family from cotton, served as a plastidic Na+ transporter. GhBASS5 encodes a membrane protein localized in the plastid envelope. It was highly expressed in cotton roots and predominantly existed in the vascular cylinder. Heterogenous expression of GhBASS5 in Arabidopsis chloroplasts promoted Na+ uptake into chloroplasts, which contributed to an increased cytoplasmic Na+ concentration. And GhBASS5-overexpressed transgenic plants showed an increase in Na+ translocation from roots to shoots and an elevated Na+ content in both roots and shoots, but a dramatic decrease in the Na+ efflux from root tissues and the K+/Na+ ratio, especially under salt stress conditions. Furthermore, overexpressing GhBASS5 greatly damaged plastid functions and enhanced salt sensitivity in transgenic Arabidopsis when compared with wild-type plants under salt stress. Additionally, the salt-responsive transporter genes that regulate K+/Na+ homeostasis were dramatically expressed in GhBASS5-overexpressed lines, especially under salt stress conditions. Taken together, our results suggest that GhBASS5 is a plastid-localized Na+ transporter, and high expression of GhBASS5 impairs salt tolerance of plants via increasing Na+ transportation and accumulation at both cell and tissue levels.
Collapse
Affiliation(s)
- Thwin Myo
- Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou, 450001, Henan, China
- Henan International Joint Laboratory of Crop Gene Resources and Improvement, School of Agricultural Sciences, Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Baoming Tian
- Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou, 450001, Henan, China
- Henan International Joint Laboratory of Crop Gene Resources and Improvement, School of Agricultural Sciences, Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Qi Zhang
- Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou, 450001, Henan, China
- Henan International Joint Laboratory of Crop Gene Resources and Improvement, School of Agricultural Sciences, Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Shasha Niu
- Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou, 450001, Henan, China
- Henan International Joint Laboratory of Crop Gene Resources and Improvement, School of Agricultural Sciences, Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Zhixian Liu
- Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou, 450001, Henan, China
- Department of Biochemistry, National University of Singapore, Singapore, 117597, Singapore
| | - Yinghui Shi
- Department of Biochemistry, National University of Singapore, Singapore, 117597, Singapore
| | - Gangqiang Cao
- Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou, 450001, Henan, China
- Henan International Joint Laboratory of Crop Gene Resources and Improvement, School of Agricultural Sciences, Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Hua Ling
- Department of Biochemistry, National University of Singapore, Singapore, 117597, Singapore
| | - Fang Wei
- Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou, 450001, Henan, China.
- Henan International Joint Laboratory of Crop Gene Resources and Improvement, School of Agricultural Sciences, Zhengzhou University, Zhengzhou, 450001, Henan, China.
| | - Gongyao Shi
- Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou, 450001, Henan, China.
- Henan International Joint Laboratory of Crop Gene Resources and Improvement, School of Agricultural Sciences, Zhengzhou University, Zhengzhou, 450001, Henan, China.
| |
Collapse
|
13
|
Xu HS, Guo SM, Zhu L, Xing JC. Growth, physiological and transcriptomic analysis of the perennial ryegrass Lolium perenne in response to saline stress. ROYAL SOCIETY OPEN SCIENCE 2020; 7:200637. [PMID: 32874657 PMCID: PMC7428229 DOI: 10.1098/rsos.200637] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 06/09/2020] [Indexed: 05/28/2023]
Abstract
Salinization of soil is a global environmental concern. To bioremediate or use saline-alkali lands, most studies focused on screening of halophytes and breeding of saline-tolerant non-halophyte vegetables. Seldom studies investigated effects of salinity on general landscape plants, which are important for landscape construction in urban areas. In the present study, effects of salinity on seed germination and seedling growth of the perennial ryegrass Lolium perenne were investigated. The final seed germination rate was not affected at salinity up to 6.4‰. Partial seedlings wilted in all saline treatments and the mortality of L. perenne was positively correlated with salinity. Treatments with salinity equal to or lower than 1.6‰ did not affect length and dry weight of shoot and root. These results suggested that L. perenne could be sowed and then grow well in low-salinity areas. To explore the underlying physiological mechanisms, contents of photosynthetic pigments and antioxidant indices were determined. The results showed that contents of chlorophyll a, b and carotenoid significantly decreased in all saline treatments, in comparison to the control. Similarly, activities of superoxide dismutase and peroxidase decreased and contents of glutathione and malondialdehyde increased in saline treatments. Additionally, transcriptome analysis identified 792 differentially expressed genes (DEGs) in L. perenne shoots between 6.4‰ saline treatment and the control. Compared with the control, genes in relation to iron transportation and amino acid metabolism were downregulated, but genes participating in energy metabolism were upregulated. These changes would inhibit toxicity of ion accumulation and provide more energy for plants to resist saline stress.
Collapse
Affiliation(s)
- Hai-Shun Xu
- College of Landscape Architecture, Nanjing Forestry University, Nanjing City, Jiangsu Province 210037, People's Republic of China
| | - Su-Ming Guo
- College of Landscape Architecture, Nanjing Forestry University, Nanjing City, Jiangsu Province 210037, People's Republic of China
| | - Lin Zhu
- Design Institution of Wujin Planning and Surveying, Changzhou City, Jiangsu Province 213100, People's Republic of China
| | - Jin-Cheng Xing
- Jiangsu Coastal Area Institute of Agricultural Sciences, Yancheng City, Jiangsu Province 224000, People's Republic of China
| |
Collapse
|
14
|
Theerawitaya C, Tisarum R, Samphumphuang T, Takabe T, Cha-um S. Expression levels of the Na +/K + transporter OsHKT2;1 and vacuolar Na +/H + exchanger OsNHX1, Na enrichment, maintaining the photosynthetic abilities and growth performances of indica rice seedlings under salt stress. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2020; 26:513-523. [PMID: 32205927 PMCID: PMC7078393 DOI: 10.1007/s12298-020-00769-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Revised: 10/31/2019] [Accepted: 01/21/2020] [Indexed: 05/20/2023]
Abstract
Salt affected soil inhibits plant growth, development and productivity, especially in case of rice crop. Ion homeostasis is a candidate defense mechanism in the salt tolerant plants or halophyte species, where the salt toxic ions are stored in the vacuoles. The aim of this investigation was to determine the OsNHX1 (a vacuolar Na+/H+ exchanger) and OsHKT2;1 (Na+/K+ transporter) regulation by salt stress (200 mM NaCl) in two rice cultivars, i.e. Pokkali (salt tolerant) and IR29 (salt susceptible), the accumulation of Na+ in the root and leaf tissues using CoroNa Green® staining dye and the associated physiological changes in test plants. Na+ content was largely increased in the root tissues of rice seedlings cv. Pokkali (15 min after salt stress) due to the higher expression of OsHKT2;1 gene (by 2.5 folds) in the root tissues. The expression of OsNHX1 gene in the leaf tissues was evidently increased in salt stressed seedlings of Pokkali, whereas it was unchanged in salt stressed seedlings of IR29. Na+ in the root tissues of both Pokkali and IR29 was enriched, when subjected to 200 mM NaCl for 12 h and easily detected in the leaf tissues of salt stressed plants exposed for 24 h, especially in cv. Pokkali. Moreover, the overexpression of OsNHX1 gene regulated the translocation of Na+ from root to leaf tissues, and compartmentation of Na+ into vacuoles, thereby maintaining the photosynthetic abilities in cv. Pokkali. Overall growth performance, maximum quantum yield (Fv/Fm), photon yield of PSII (ΦPSII) and net photosynthetic rate (Pn) was improved in salt stressed leaves of Pokkali than those in salt stressed IR29.
Collapse
Affiliation(s)
- Cattarin Theerawitaya
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), 113 Paholyothin Rd., Khlong Nuang, Khlong Luang, Pathum Thani 12120 Thailand
| | - Rujira Tisarum
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), 113 Paholyothin Rd., Khlong Nuang, Khlong Luang, Pathum Thani 12120 Thailand
| | - Thapanee Samphumphuang
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), 113 Paholyothin Rd., Khlong Nuang, Khlong Luang, Pathum Thani 12120 Thailand
| | - Taruhiro Takabe
- Research Institute Meijo University, 1-501 Shiogamagushi, Tenpaku-ku, Nagoya, 468-8502 Japan
| | - Suriyan Cha-um
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), 113 Paholyothin Rd., Khlong Nuang, Khlong Luang, Pathum Thani 12120 Thailand
| |
Collapse
|
15
|
Comparison of Biochemical, Anatomical, Morphological, and Physiological Responses to Salinity Stress in Wheat and Barley Genotypes Deferring in Salinity Tolerance. AGRONOMY-BASEL 2020. [DOI: 10.3390/agronomy10010127] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A greenhouse hydroponic experiment was performed using salt-tolerant (cv. Suntop) and -sensitive (Sunmate) wheat cultivars and a salt-tolerant barley cv. CM72 to evaluate how cultivar and species differ in response to salinity stress. Results showed that wheat cv. Suntop performed high tolerance to salinity, being similar tolerance to salinity with CM72, compared with cv. Sunmate. Similar to CM72, Suntop recorded less salinity induced increase in malondialdehyde (MDA) accumulation and less reduction in plant height, net photosynthetic rate (Pn), chlorophyll content, and biomass than in sensitive wheat cv. Sunmate. Significant time-course and cultivar-dependent changes were observed in the activities of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) in roots and leaves after salinity treatment. Higher activities were found in CM72 and Suntop compared to Sunmate. Furthermore, a clear modification was observed in leaf and root ultrastructure after NaCl treatment with more obvious changes in the sensitive wheat cv. Sunmate, rather than in CM72 and Suntop. Although differences were observed between CM72 and Suntop in the growth and biochemical traits assessed and modified by salt stress, the differences were negligible in comparison with the general response to the salt stress of sensitive wheat cv. Sunmate. In addition, salinity stress induced an increase in the Na+ and Na+/K+ ratio but a reduction in K+ concentrations, most prominently in Sunmate and followed by Suntop and CM72.
Collapse
|
16
|
Gul M, Wakeel A, Steffens D, Lindberg S. Potassium-induced decrease in cytosolic Na + alleviates deleterious effects of salt stress on wheat (Triticum aestivum L.). PLANT BIOLOGY (STUTTGART, GERMANY) 2019; 21:825-831. [PMID: 31034750 DOI: 10.1111/plb.12999] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 04/18/2019] [Indexed: 05/24/2023]
Abstract
Accumulation of NaCl in soil causes osmotic stress in plants, and sodium (Na+ ) and chloride (Cl- ) cause ion toxicity, but also reduce the potassium (K+ ) uptake by plant roots and stimulate the K+ efflux through the cell membrane. Thus, decreased K+ /Na+ ratio in plant tissue lead us to hypothesise that elevated levels of K+ in nutrient medium enhance this ratio in plant tissue and cytosol to improve enzyme activation, osmoregulation and charge balance. In this study, wheat was cultivated at different concentrations of K+ (2.2, 4.4 or 8.8 mm) with or without salinity (1, 60 or 120 mm NaCl) and the effects on growth, root and shoot Na+ and K+ distribution and grain yield were determined. Also, the cytosolic Na+ concentration was investigated, as well as photosynthesis rate and water potential. Salinity reduced fresh weight of both shoots and roots and dry weight of roots. The grain yield was significantly reduced under Na+ stress and improved with elevated K+ fertilisation. Elevated K+ level during cultivation prevented the accumulation of Na+ into the cytosol of both shoot and root protoplasts. Wheat growth at vegetative stage was transiently reduced at the highest K+ concentration, perhaps due to plants' efforts to overcome a high solute concentration in the plant tissue, nevertheless grain yield was increased at both K+ levels. In conclusion, a moderately elevated K+ application to wheat seedlings reduces tissue as well as cytosolic Na+ concentration and enhances wheat growth and grain yield by mitigating the deleterious effects of Na+ toxicity.
Collapse
Affiliation(s)
- M Gul
- Department of Soil Science, Bahauddin Zakariya University, Multan, Pakistan
- Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad, Pakistan
- Department of Ecology, Environment and Plant Sciences, University of Stockholm, Stockholm, Sweden
| | - A Wakeel
- Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad, Pakistan
| | - D Steffens
- Institute of Plant Nutrition, Interdisciplinary Research Center (IFZ), Justus Liebig University, Giessen, Germany
| | - S Lindberg
- Department of Ecology, Environment and Plant Sciences, University of Stockholm, Stockholm, Sweden
| |
Collapse
|
17
|
Premkumar A, Lindberg S, Lager I, Rasmussen U, Schulz A. Arabidopsis PLDs with C2-domain function distinctively in hypoxia. PHYSIOLOGIA PLANTARUM 2019; 167:90-110. [PMID: 30417386 DOI: 10.1111/ppl.12874] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 10/31/2018] [Accepted: 11/07/2018] [Indexed: 06/09/2023]
Abstract
Hypoxia (oxygen deprivation) causes metabolic disturbances at physiological, biochemical and genetic levels and results in decreased plant growth and development. Phospholipase D (PLD)-mediated signaling was reported for abiotic and biotic stress signaling events in plants. To investigate the participatory role of PLDs also in hypoxia signaling, we used wild type of Arabidopsis thaliana and 10 pld isoform mutants containing C2-domain. Hypoxia-induced changes in three major signaling players, namely, cytosolic free calcium (Ca2+ cyt ), reactive oxygen species (ROS) and phosphatidic acid (PA), were determined in mesophyll protoplasts. The Ca2+ cyt and ROS levels were monitored by fluorescence microscopy and confocal imaging, while PA levels were quantified by an enzymatic method. Our findings reveal that the elevations of cytosolic calcium and PA are reduced in all the 10 mutants dysfunctional in PLD isoforms. The hypoxia-related changes in both calcium and ROS show different kinetic patterns depending on the type of PLD studied. Pharmacological experiments confirm that both external and internal sources contribute to calcium and ROS accumulation under hypoxia. PLDα1-3, PLDβ1 and PLDγ1-3 are likely involved in calcium signaling under hypoxia as well as in PA production, while all investigated PLDs, except for PLDγ3, take part in ROS elevation.
Collapse
Affiliation(s)
- Albert Premkumar
- Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Sylvia Lindberg
- Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Ida Lager
- Department of Plant Breeding, Swedish University of Agricultural Sciences, SE-230 53 Alnarp, Sweden
| | - Ulla Rasmussen
- Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Alexander Schulz
- Center for Advanced Bioimaging, Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Fredriksberg, Denmark
| |
Collapse
|
18
|
Hamam AM, Coskun D, Britto DT, Plett D, Kronzucker HJ. Plasma-membrane electrical responses to salt and osmotic gradients contradict radiotracer kinetics, and reveal Na +-transport dynamics in rice (Oryza sativa L.). PLANTA 2019; 249:1037-1051. [PMID: 30498958 DOI: 10.1007/s00425-018-3059-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 11/23/2018] [Indexed: 05/25/2023]
Abstract
A systematic analysis of NaCl-dependent, plasma-membrane depolarization (∆∆Ψ) in rice roots calls into question the current leading model of rapid membrane cycling of Na+ under salt stress. To investigate the character and mechanisms of Na+ influx into roots, Na+-dependent changes in plasma-membrane electrical potentials (∆∆Ψ) were measured in root cells of intact rice (Oryza sativa L., cv. Pokkali) seedlings. As external sodium concentrations ([Na+]ext) were increased in a step gradient from 0 to 100 mM, membrane potentials depolarized in a saturable manner, fitting a Michaelis-Menten model and contradicting the linear (non-saturating) models developed from radiotracer studies. Clear differences in saturation patterns were found between plants grown under low- and high-nutrient (LN and HN) conditions, with LN plants showing greater depolarization and higher affinity for Na+ (i.e., higher Vmax and lower Km) than HN plants. In addition, counterion effects on ∆∆Ψ were pronounced in LN plants (with ∆∆Ψ decreasing in the order: Cl- > SO42- > HPO 4 2- ), but not seen in HN plants. When effects of osmotic strength, Cl- influx, K+ efflux, and H+-ATPase activity on ∆∆Ψ were accounted for, resultant Km and Vmax values suggested that a single, dominant Na+-transport mechanism was operating under each nutritional condition, with Km values of 1.2 and 16 mM for LN and HN plants, respectively. Comparing saturating patterns of depolarization to linear patterns of 24Na+ radiotracer influx leads to the conclusion that electrophysiological and tracer methods do not report the same phenomena and that the current model of rapid transmembrane sodium cycling may require revision.
Collapse
Affiliation(s)
- Ahmed M Hamam
- Department of Biological Sciences and Canadian Centre for World Hunger Research (CCWHR), University of Toronto, Toronto, ON, M1C 1A4, Canada
| | - Devrim Coskun
- Département de Phytologie, Faculté des Sciences de l'Agriculture et de l'Alimentation (FSAA), Université Laval, Québec, QC, G1V 0A6, Canada
| | - Dev T Britto
- Department of Biological Sciences and Canadian Centre for World Hunger Research (CCWHR), University of Toronto, Toronto, ON, M1C 1A4, Canada
| | - Darren Plett
- School of Agriculture and Food, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Herbert J Kronzucker
- School of Agriculture and Food, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, VIC, 3010, Australia.
| |
Collapse
|
19
|
Das P, Manna I, Sil P, Bandyopadhyay M, Biswas AK. Exogenous silicon alters organic acid production and enzymatic activity of TCA cycle in two NaCl stressed indica rice cultivars. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2019; 136:76-91. [PMID: 30658287 DOI: 10.1016/j.plaphy.2018.12.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 12/24/2018] [Accepted: 12/27/2018] [Indexed: 06/09/2023]
Abstract
The activities of TCA cycle enzymes viz., pyruvate dehydrogenase, citrate synthase, isocitrate dehydrogenase, succinate dehydrogenase and malate dehydrogenase as well as levels of different organic acids viz., pyruvic acid, citric acid, succinic acid and malic acid were studied in two rice cultivars viz. cv. Nonabokra and cv. MTU 1010 differing in salt tolerance grown under 25, 50 and 100 mM NaCl salinity levels. A contrasting response to salt stress on enzyme activities of TCA cycle and accumulation of organic acid was observed between two cultivars during twenty-one days period of study. Salinity caused enhanced organic acid production and increase in all five enzyme activities in cv. Nonabokra whereas in cv. MTU 1010 decrease in both organic acid production and enzymes activities were noted. Joint application of exogenous silicon along with NaCl, altered the organic acids levels and activities of enzymes in both cultivars of rice seedlings conferring tolerance against salt induced stress. Rice cv. MTU 1010 showed better response to exogenous silicon on parameters tested compared to cv. Nonabokra.
Collapse
Affiliation(s)
- Prabal Das
- Plant Physiology and Biochemistry Laboratory, Centre of Advanced Study, Department of Botany, Ballygunge Science College, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, India
| | - Indrani Manna
- Plant Molecular Cytogenetics Laboratory, Centre of Advanced Study, Department of Botany, Ballygunge Science College, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, India
| | - Palin Sil
- Plant Physiology and Biochemistry Laboratory, Centre of Advanced Study, Department of Botany, Ballygunge Science College, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, India
| | - Maumita Bandyopadhyay
- Plant Molecular Cytogenetics Laboratory, Centre of Advanced Study, Department of Botany, Ballygunge Science College, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, India.
| | - Asok K Biswas
- Plant Physiology and Biochemistry Laboratory, Centre of Advanced Study, Department of Botany, Ballygunge Science College, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, India.
| |
Collapse
|
20
|
Isayenkov SV, Maathuis FJM. Plant Salinity Stress: Many Unanswered Questions Remain. FRONTIERS IN PLANT SCIENCE 2019; 10:80. [PMID: 30828339 PMCID: PMC6384275 DOI: 10.3389/fpls.2019.00080] [Citation(s) in RCA: 390] [Impact Index Per Article: 78.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 01/18/2019] [Indexed: 05/19/2023]
Abstract
Salinity is a major threat to modern agriculture causing inhibition and impairment of crop growth and development. Here, we not only review recent advances in salinity stress research in plants but also revisit some basic perennial questions that still remain unanswered. In this review, we analyze the physiological, biochemical, and molecular aspects of Na+ and Cl- uptake, sequestration, and transport associated with salinity. We discuss the role and importance of symplastic versus apoplastic pathways for ion uptake and critically evaluate the role of different types of membrane transporters in Na+ and Cl- uptake and intercellular and intracellular ion distribution. Our incomplete knowledge regarding possible mechanisms of salinity sensing by plants is evaluated. Furthermore, a critical evaluation of the mechanisms of ion toxicity leads us to believe that, in contrast to currently held ideas, toxicity only plays a minor role in the cytosol and may be more prevalent in the vacuole. Lastly, the multiple roles of K+ in plant salinity stress are discussed.
Collapse
Affiliation(s)
- Stanislav V. Isayenkov
- Department of Plant Food Products and Biofortification, Institute of Food Biotechnology and Genomics NAS of Ukraine, Kyiv, Ukraine
| | | |
Collapse
|
21
|
Kaya C, Akram NA, Ashraf M. Influence of exogenously applied nitric oxide on strawberry (Fragaria × ananassa) plants grown under iron deficiency and/or saline stress. PHYSIOLOGIA PLANTARUM 2019; 165:247-263. [PMID: 30091474 DOI: 10.1111/ppl.12818] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 08/01/2018] [Accepted: 08/06/2018] [Indexed: 05/26/2023]
Abstract
A study was carried out to assess the protective effects of exogenously applied nitric oxide (NO) in the form of its donor sodium nitroprusside (SNP) to strawberry seedlings (Fragaria × ananassa cv. Camarosa) grown under iron deficiency (ID), salinity stress or combination of both. The experimental design contained control, 0.1 mM FeSO4 (ID, Fe deficiency); 50 mM NaCl (S, Salinity) and ID + S. Plants were sprayed with 0.1 mM SNP or 0.1 mM sodium ferrocyanide, an analogue of SNP containing no NO. The deleterious effects of ID + S treatments on plant fresh and dry matters, total chlorophyll and chlorophyll fluorescence were more striking than those caused by the ID or S treatment alone. Furthermore, combination of salinity and iron stress exacerbated electrolyte leakage (EL) and the levels of malondialdehyde (MDA) and hydrogen peroxide (H2 O2 ) in plant leaves compared to those in plants grown with either of the single stresses. NO treatment effectively reduced EL, MDA and H2 O2 in plants grown under stress conditions applied singly or in combination. Salt stress alone and with ID reduced the superoxide dismutase (EC1.15.1.1) and catalase (EC 1.11.1.6) activities but increased that of POD (EC 1.17.1.7). Exogenously applied NO led to significant changes in antioxidant enzyme activities in either ID or S than those by ID+S. Overall, exogenously applied NO was more effective in mitigating the stress-induced adverse effects on the strawberry plants exposed to a single stress than those due to the combination of both stresses.
Collapse
Affiliation(s)
- Cengiz Kaya
- Soil Science and Plant Nutrition Department, Harran University, Sanliurfa, Turkey
| | - Nudrat A Akram
- Department of Botany, GC University Faisalabad, Faisalabad, Pakistan
| | | |
Collapse
|
22
|
Kholghi M, Toorchi M, Bandehagh A, Ostendorp A, Ostendorp S, Hanhart P, Kehr J. Comparative proteomic analysis of salt-responsive proteins in canola roots by 2-DE and MALDI-TOF MS. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2019; 1867:227-236. [PMID: 30611781 DOI: 10.1016/j.bbapap.2018.12.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 12/14/2018] [Accepted: 12/30/2018] [Indexed: 02/08/2023]
Abstract
Salinity stress is a major abiotic stress that affects plant growth and limits crop production. Roots are the primary site of salinity perception, and salt sensitivity in roots limits the productivity of the entire plant. To better understand salt stress responses in canola, we performed a comparative proteomic analysis of roots from the salt-tolerant genotype Safi-7 and the salt-sensitive genotype Zafar. Plants were exposed to 0, 150, and 300 mM NaCl. Our physiological and morphological observations confirmed that Safi-7 was more salt-tolerant than Zafar. The root proteins were separated by two-dimensional gel electrophoresis and MALDI-TOF mass spectrometry was applied to identify proteins regulated in response to salt stress. We identified 36 and 25 protein spots whose abundance was significantly affected by salt stress in roots of plants from the tolerant and susceptible genotype, respectively. Functional classification analysis revealed that the differentially expressed proteins from the tolerant genotype could be assigned to 14 functional categories, while those from the susceptible genotype could be classified into 9 functional categories. The most significant differences concerned proteins involved in glycolysis (Glyceraldehyde-3-phosphate dehydrogenase, Fructose-bisphosphate aldolase, Phosphoglycerate kinase 3), stress (heat shock proteins), Redox regulation (Glutathione S-transferase DHAR1, L-ascorbate peroxidase), energy metabolism (ATP synthase subunit B), and transport (V-type proton ATPase subunit B1) which were increased only in the tolerant line under salt stress. Our results provide the basis for further elucidating the molecular mechanisms of salt-tolerance and will be helpful for breeding salt-tolerant canola cultivars.
Collapse
Affiliation(s)
- Maryam Kholghi
- Department of Plant Breeding and Biotechnology, Faculty of Agriculture, University of Tabriz, Tabriz, Iran
| | - Mahmoud Toorchi
- Department of Plant Breeding and Biotechnology, Faculty of Agriculture, University of Tabriz, Tabriz, Iran
| | - Ali Bandehagh
- Department of Plant Breeding and Biotechnology, Faculty of Agriculture, University of Tabriz, Tabriz, Iran
| | - Anna Ostendorp
- Molecular Plant Genetics, Universität Hamburg, Biozentrum Klein Flottbek, Ohnhorststr. 18, 22609 Hamburg, Germany
| | - Steffen Ostendorp
- Molecular Plant Genetics, Universität Hamburg, Biozentrum Klein Flottbek, Ohnhorststr. 18, 22609 Hamburg, Germany
| | - Patrizia Hanhart
- Molecular Plant Genetics, Universität Hamburg, Biozentrum Klein Flottbek, Ohnhorststr. 18, 22609 Hamburg, Germany
| | - Julia Kehr
- Molecular Plant Genetics, Universität Hamburg, Biozentrum Klein Flottbek, Ohnhorststr. 18, 22609 Hamburg, Germany.
| |
Collapse
|
23
|
Grossmann G, Krebs M, Maizel A, Stahl Y, Vermeer JEM, Ott T. Green light for quantitative live-cell imaging in plants. J Cell Sci 2018; 131:jcs.209270. [PMID: 29361538 DOI: 10.1242/jcs.209270] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Plants exhibit an intriguing morphological and physiological plasticity that enables them to thrive in a wide range of environments. To understand the cell biological basis of this unparalleled competence, a number of methodologies have been adapted or developed over the last decades that allow minimal or non-invasive live-cell imaging in the context of tissues. Combined with the ease to generate transgenic reporter lines in specific genetic backgrounds or accessions, we are witnessing a blooming in plant cell biology. However, the imaging of plant cells entails a number of specific challenges, such as high levels of autofluorescence, light scattering that is caused by cell walls and their sensitivity to environmental conditions. Quantitative live-cell imaging in plants therefore requires adapting or developing imaging techniques, as well as mounting and incubation systems, such as micro-fluidics. Here, we discuss some of these obstacles, and review a number of selected state-of-the-art techniques, such as two-photon imaging, light sheet microscopy and variable angle epifluorescence microscopy that allow high performance and minimal invasive live-cell imaging in plants.
Collapse
Affiliation(s)
- Guido Grossmann
- Centre for Organismal Studies (COS), Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany.,Excellence Cluster CellNetworks, Heidelberg University, 69120 Heidelberg, Germany
| | - Melanie Krebs
- Centre for Organismal Studies (COS), Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Alexis Maizel
- Centre for Organismal Studies (COS), Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Yvonne Stahl
- Institute for Developmental Genetics, Heinrich-Heine University, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Joop E M Vermeer
- Laboratory for Cell Biology, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Thomas Ott
- Faculty of Biology, Cell Biology, University of Freiburg, Schänzlestr. 1, 79104 Freiburg, Germany
| |
Collapse
|
24
|
Paleari L, Movedi E, Confalonieri R. Trait-based model development to support breeding programs. A case study for salt tolerance and rice. Sci Rep 2017; 7:4352. [PMID: 28659583 PMCID: PMC5489522 DOI: 10.1038/s41598-017-04022-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 05/08/2017] [Indexed: 01/08/2023] Open
Abstract
Eco-physiological models are increasingly used to analyze G × E × M interactions to support breeding programs via the design of ideotypes for specific contexts. However, available crop models are only partly suitable for this purpose, since they often lack clear relationships between parameters and traits breeders are working on. Taking salt stress tolerance and rice as a case study, we propose a paradigm shift towards the building of ideotyping-specific models explicitly around traits involved in breeding programs. Salt tolerance is a complex trait relying on different physiological processes that can be alternatively selected to improve the overall crop tolerance. We developed a new model explicitly accounting for these traits and we evaluated its performance using data from growth chamber experiments (e.g., R2 ranged from 0.74 to 0.94 for the biomass of different plant organs). Using the model, we were able to show how an increase in the overall tolerance can derive from completely different physiological mechanisms according to soil/water salinity dynamics. The study demonstrated that a trait-based approach can increase the usefulness of mathematical models for supporting breeding programs.
Collapse
Affiliation(s)
- Livia Paleari
- University of Milan, DISAA, Cassandra lab, via Celoria 2, 20133, Milano, Italy.
| | - Ermes Movedi
- University of Milan, DISAA, Cassandra lab, via Celoria 2, 20133, Milano, Italy
| | | |
Collapse
|
25
|
De Leon TB, Linscombe S, Subudhi PK. Molecular Dissection of Seedling Salinity Tolerance in Rice (Oryza sativa L.) Using a High-Density GBS-Based SNP Linkage Map. RICE (NEW YORK, N.Y.) 2016; 9:52. [PMID: 27696287 PMCID: PMC5045836 DOI: 10.1186/s12284-016-0125-2] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 09/23/2016] [Indexed: 05/23/2023]
Abstract
BACKGROUND Salinity is one of the many abiotic stresses limiting rice production worldwide. Several studies were conducted to identify quantitative trait loci (QTLs) for traits associated to salinity tolerance. However, due to large confidence interval for the position of QTLs, utility of reported QTLs and the associated markers has been limited in rice breeding programs. The main objective of this study is to construct a high-density rice genetic map for identification QTLs and candidate genes for salinity tolerance at seedling stage. RESULTS We evaluated a population of 187 recombinant inbred lines (RILs) developed from a cross between Bengal and Pokkali for nine traits related to salinity tolerance. A total of 9303 SNP markers generated by genotyping-by-sequencing (GBS) were mapped to 2817 recombination points. The genetic map had a total map length of 1650 cM with an average resolution of 0.59 cM between markers. For nine traits, a total of 85 additive QTLs were identified, of which, 16 were large-effect QTLs and the rest were small-effect QTLs. The average interval size of QTL was about 132 kilo base pairs (Kb). Eleven of the 85 additive QTLs validated 14 reported QTLs for shoot potassium concentration, sodium-potassium ratio, salt injury score, plant height, and shoot dry weight. Epistatic QTL mapping identified several pairs of QTLs that significantly contributed to the variation of traits. The QTL for high shoot K+ concentration was mapped near the qSKC1 region. However, candidate genes within the QTL interval were a CC-NBS-LRR protein, three uncharacterized genes, and transposable elements. Additionally, many QTLs flanked small chromosomal intervals containing few candidate genes. Annotation of the genes located within QTL intervals indicated that ion transporters, osmotic regulators, transcription factors, and protein kinases may play essential role in various salt tolerance mechanisms. CONCLUSION The saturation of SNP markers in our linkage map increased the resolution of QTL mapping. Our study offers new insights on salinity tolerance and presents useful candidate genes that will help in marker-assisted gene pyramiding to develop salt tolerant rice varieties.
Collapse
Affiliation(s)
- Teresa B De Leon
- School of Plant, Environmental, and Soil Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA, USA
| | - Steven Linscombe
- Rice Research Station, Louisiana State University Agricultural Center, Rayne, LA, USA
| | - Prasanta K Subudhi
- School of Plant, Environmental, and Soil Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA, USA.
| |
Collapse
|
26
|
Improvement of Salinity Stress Tolerance in Rice: Challenges and Opportunities. AGRONOMY-BASEL 2016. [DOI: 10.3390/agronomy6040054] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
|
27
|
Ahmad I, Mian A, Maathuis FJM. Overexpression of the rice AKT1 potassium channel affects potassium nutrition and rice drought tolerance. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:2689-98. [PMID: 26969743 PMCID: PMC4861017 DOI: 10.1093/jxb/erw103] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Potassium (K(+)) is the most important cationic nutrient for all living organisms and has roles in most aspects of plant physiology. To assess the impact of one of the main K(+) uptake components, the K(+) inward rectifying channel AKT1, we characterized both loss of function and overexpression of OsAKT1 in rice. In many conditions, AKT1 expression correlated with K(+) uptake and tissue K(+) levels. No salinity-related growth phenotype was observed for either loss or gain of function mutants. However, a correlation between AKT1 expression and root Na(+) when the external Na/K ratio was high suggests that there may be a role for AKT1 in Na(+) uptake in such conditions. In contrast to findings with Arabidopsis thaliana, we did not detect any change in growth of AKT1 loss of function mutants in the presence of NH4 (+) Nevertheless, NH4 (+)-dependent inhibition was detected during K(+) uptake assays in loss of function and wild type plants, depending on pre-growth conditions. The most prominent result of OsAKT1 overexpression was a reduction in sensitivity to osmotic/drought stress in transgenic plants: the data suggest that AKT1 overexpression improved rice osmotic and drought stress tolerance by increasing tissue levels of K(+), especially in the root.
Collapse
Affiliation(s)
- Izhar Ahmad
- Department of Biology, University of York, York YO10 5DD, UK
| | - Afaq Mian
- Department of Biology, University of York, York YO10 5DD, UK
| | | |
Collapse
|
28
|
King GJ. Crop epigenetics and the molecular hardware of genotype × environment interactions. FRONTIERS IN PLANT SCIENCE 2015; 6:968. [PMID: 26594221 PMCID: PMC4635209 DOI: 10.3389/fpls.2015.00968] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 10/22/2015] [Indexed: 05/04/2023]
Abstract
Crop plants encounter thermal environments which fluctuate on a diurnal and seasonal basis. Future climate resilient cultivars will need to respond to thermal profiles reflecting more variable conditions, and harness plasticity that involves regulation of epigenetic processes and complex genomic regulatory networks. Compartmentalization within plant cells insulates the genomic central processing unit within the interphase nucleus. This review addresses the properties of the chromatin hardware in which the genome is embedded, focusing on the biophysical and thermodynamic properties of DNA, histones and nucleosomes. It explores the consequences of thermal and ionic variation on the biophysical behavior of epigenetic marks such as DNA cytosine methylation (5mC), and histone variants such as H2A.Z, and how these contribute to maintenance of chromatin integrity in the nucleus, while enabling specific subsets of genes to be regulated. Information is drawn from theoretical molecular in vitro studies as well as model and crop plants and incorporates recent insights into the role epigenetic processes play in mediating between environmental signals and genomic regulation. A preliminary speculative framework is outlined, based on the evidence of what appears to be a cohesive set of interactions at molecular, biophysical and electrostatic level between the various components contributing to chromatin conformation and dynamics. It proposes that within plant nuclei, general and localized ionic homeostasis plays an important role in maintaining chromatin conformation, whilst maintaining complex genomic regulation that involves specific patterns of epigenetic marks. More generally, reversible changes in DNA methylation appear to be consistent with the ability of nuclear chromatin to manage variation in external ionic and temperature environment. Whilst tentative, this framework provides scope to develop experimental approaches to understand in greater detail the internal environment of plant nuclei. It is hoped that this will generate a deeper understanding of the molecular mechanisms underlying genotype × environment interactions that may be beneficial for long-term improvement of crop performance in less predictable climates.
Collapse
Affiliation(s)
- Graham J. King
- Southern Cross Plant Science, Southern Cross University, Lismore, NSW, Australia
- National Key Laboratory for Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
- Crops for the Future, Biotechnology and Breeding Systems, Semenyih, Malaysia
| |
Collapse
|
29
|
Foster KJ, Miklavcic SJ. Toward a biophysical understanding of the salt stress response of individual plant cells. J Theor Biol 2015; 385:130-42. [DOI: 10.1016/j.jtbi.2015.08.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 08/22/2015] [Accepted: 08/25/2015] [Indexed: 10/23/2022]
|
30
|
Volkov V. Salinity tolerance in plants. Quantitative approach to ion transport starting from halophytes and stepping to genetic and protein engineering for manipulating ion fluxes. FRONTIERS IN PLANT SCIENCE 2015; 6:873. [PMID: 26579140 PMCID: PMC4621421 DOI: 10.3389/fpls.2015.00873] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 10/01/2015] [Indexed: 05/18/2023]
Abstract
Ion transport is the fundamental factor determining salinity tolerance in plants. The Review starts from differences in ion transport between salt tolerant halophytes and salt-sensitive plants with an emphasis on transport of potassium and sodium via plasma membranes. The comparison provides introductory information for increasing salinity tolerance. Effects of salt stress on ion transport properties of membranes show huge opportunities for manipulating ion fluxes. Further steps require knowledge about mechanisms of ion transport and individual genes of ion transport proteins. Initially, the Review describes methods to measure ion fluxes, the independent set of techniques ensures robust and reliable basement for quantitative approach. The Review briefly summarizes current data concerning Na(+) and K(+) concentrations in cells, refers to primary thermodynamics of ion transport and gives special attention to individual ion channels and transporters. Simplified scheme of a plant cell with known transport systems at the plasma membrane and tonoplast helps to imagine the complexity of ion transport and allows choosing specific transporters for modulating ion transport. The complexity is enhanced by the influence of cell size and cell wall on ion transport. Special attention is given to ion transporters and to potassium and sodium transport by HKT, HAK, NHX, and SOS1 proteins. Comparison between non-selective cation channels and ion transporters reveals potential importance of ion transporters and the balance between the two pathways of ion transport. Further on the Review describes in detail several successful attempts to overexpress or knockout ion transporters for changing salinity tolerance. Future perspectives are questioned with more attention given to promising candidate ion channels and transporters for altered expression. Potential direction of increasing salinity tolerance by modifying ion channels and transporters using single point mutations is discussed and questioned. An alternative approach from synthetic biology is to create new regulation networks using novel transport proteins with desired properties for transforming agricultural crops. The approach had not been widely used earlier; it leads also to theoretical and pure scientific aspects of protein chemistry, structure-function relations of membrane proteins, systems biology and physiology of stress and ion homeostasis. Summarizing, several potential ways are aimed at required increase in salinity tolerance of plants of interest.
Collapse
Affiliation(s)
- Vadim Volkov
- Faculty of Life Sciences and Computing, London Metropolitan UniversityLondon, UK
| |
Collapse
|
31
|
Britto DT, Kronzucker HJ. Sodium efflux in plant roots: what do we really know? JOURNAL OF PLANT PHYSIOLOGY 2015; 186-187:1-12. [PMID: 26318642 DOI: 10.1016/j.jplph.2015.08.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 08/03/2015] [Accepted: 08/03/2015] [Indexed: 05/27/2023]
Abstract
The efflux of sodium (Na(+)) ions across the plasma membrane of plant root cells into the external medium is surprisingly poorly understood. Nevertheless, Na(+) efflux is widely regarded as a major mechanism by which plants restrain the rise of Na(+) concentrations in the cytosolic compartments of root cells and, thus, achieve a degree of tolerance to saline environments. In this review, several key ideas and bodies of evidence concerning root Na(+) efflux are summarized with a critical eye. Findings from decades past are brought to bear on current thinking, and pivotal studies are discussed, both "purely physiological", and also with regard to the SOS1 protein, the only major Na(+) efflux transporter that has, to date, been genetically characterized. We find that the current model of rapid transmembrane sodium cycling (RTSC), across the plasma membrane of root cells, is not adequately supported by evidence from the majority of efflux studies. An alternative hypothesis cannot be ruled out, that most Na(+) tracer efflux from the root in the salinity range does not proceed across the plasma membrane, but through the apoplast. Support for this idea comes from studies showing that Na(+) efflux, when measured with tracers, is rarely affected by the presence of inhibitors or the ionic composition in saline rooting media. We conclude that the actual efflux of Na(+) across the plasma membrane of root cells may be much more modest than what is often reported in studies using tracers, and may predominantly occur in the root tips, where SOS1 expression has been localized.
Collapse
Affiliation(s)
- D T Britto
- University of Toronto, Canadian Centre for World Hunger Research, Canada
| | - H J Kronzucker
- University of Toronto, Canadian Centre for World Hunger Research, Canada.
| |
Collapse
|
32
|
Hazman M, Hause B, Eiche E, Nick P, Riemann M. Increased tolerance to salt stress in OPDA-deficient rice ALLENE OXIDE CYCLASE mutants is linked to an increased ROS-scavenging activity. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:3339-52. [PMID: 25873666 PMCID: PMC4449546 DOI: 10.1093/jxb/erv142] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Salinity stress represents a global constraint for rice, the most important staple food worldwide. Therefore the role of the central stress signal jasmonate for the salt response was analysed in rice comparing the responses to salt stress for two jasmonic acid (JA) biosynthesis rice mutants (cpm2 and hebiba) impaired in the function of ALLENE OXIDE CYCLASE (AOC) and their wild type. The aoc mutants were less sensitive to salt stress. Interestingly, both mutants accumulated smaller amounts of Na(+) ions in their leaves, and showed better scavenging of reactive oxygen species (ROS) under salt stress. Leaves of the wild type and JA mutants accumulated similar levels of abscisic acid (ABA) under stress conditions, and the levels of JA and its amino acid conjugate, JA-isoleucine (JA-Ile), showed only subtle alterations in the wild type. In contrast, the wild type responded to salt stress by strong induction of the JA precursor 12-oxophytodienoic acid (OPDA), which was not observed in the mutants. Transcript levels of representative salinity-induced genes were induced less in the JA mutants. The absence of 12-OPDA in the mutants correlated not only with a generally increased ROS-scavenging activity, but also with the higher activity of specific enzymes in the antioxidative pathway, such as glutathione S-transferase, and fewer symptoms of damage as, for example, indicated by lower levels of malondialdehyde. The data are interpreted in a model where the absence of OPDA enhanced the antioxidative power in mutant leaves.
Collapse
Affiliation(s)
- Mohamed Hazman
- Botanical Institute, Molecular Cell Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany Agricultural Genetic Engineering Research Institute (AGERI), Agricultural Research Centre (ARC), Giza, Egypt
| | - Bettina Hause
- Cell and Metabolic Biology, Leibniz Institute of Plant Biochemistry (IPB), Halle, Germany
| | - Elisabeth Eiche
- Institute of Applied Geosciences, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Peter Nick
- Botanical Institute, Molecular Cell Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Michael Riemann
- Botanical Institute, Molecular Cell Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| |
Collapse
|
33
|
De Leon TB, Linscombe S, Gregorio G, Subudhi PK. Genetic variation in Southern USA rice genotypes for seedling salinity tolerance. FRONTIERS IN PLANT SCIENCE 2015; 6:374. [PMID: 26074937 PMCID: PMC4444739 DOI: 10.3389/fpls.2015.00374] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 05/11/2015] [Indexed: 05/02/2023]
Abstract
The success of a rice breeding program in developing salt tolerant varieties depends on genetic variation and the salt stress response of adapted and donor rice germplasm. In this study, we used a combination of morphological and physiological traits in multivariate analyses to elucidate the phenotypic and genetic variation in salinity tolerance of 30 Southern USA rice genotypes, along with 19 donor genotypes with varying degree of tolerance. Significant genotypic variation and correlations were found among the salt injury score (SIS), ion leakage, chlorophyll reduction, shoot length reduction, shoot K(+) concentration, and shoot Na(+)/K(+) ratio. Using these parameters, the combined methods of cluster analysis and discriminant analysis validated the salinity response of known genotypes and classified most of the USA varieties into sensitive groups, except for three and seven varieties placed in the tolerant and moderately tolerant groups, respectively. Discriminant function and MANOVA delineated the differences in tolerance and suggested no differences between sensitive and highly sensitive (HS) groups. DNA profiling using simple sequence repeat markers showed narrow genetic diversity among USA genotypes. However, the overall genetic clustering was mostly due to subspecies and grain type differentiation and not by varietal grouping based on salinity tolerance. Among the donor genotypes, Nona Bokra, Pokkali, and its derived breeding lines remained the donors of choice for improving salinity tolerance during the seedling stage. However, due to undesirable agronomic attributes and photosensitivity of these donors, alternative genotypes such as TCCP266, Geumgangbyeo, and R609 are recommended as useful and novel sources of salinity tolerance for USA rice breeding programs.
Collapse
Affiliation(s)
- Teresa B. De Leon
- School of Plant, Environmental, and Soil Sciences, Louisiana State University Agricultural CenterBaton Rouge, LA, USA
| | - Steven Linscombe
- Rice Research Station, Louisiana State University Agricultural CenterRayne, LA, USA
| | - Glenn Gregorio
- Plant Breeding, Genetics, and Biotechnology Division, International Rice Research InstituteLos Baños, Philippines
| | - Prasanta K. Subudhi
- School of Plant, Environmental, and Soil Sciences, Louisiana State University Agricultural CenterBaton Rouge, LA, USA
- *Correspondence: Prasanta K. Subudhi, School of Plant, Environmental, and Soil Sciences, Louisiana State University Agricultural Center, LSU-SPESS, 104 MB Sturgis Hall, Baton Rouge, LA 70803, USA
| |
Collapse
|
34
|
Mansour MMF. The plasma membrane transport systems and adaptation to salinity. JOURNAL OF PLANT PHYSIOLOGY 2014; 171:1787-800. [PMID: 25262536 DOI: 10.1016/j.jplph.2014.08.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 08/18/2014] [Accepted: 08/21/2014] [Indexed: 05/09/2023]
Abstract
Salt stress represents one of the environmental challenges that drastically affect plant growth and yield. Evidence suggests that glycophytes and halophytes have a salt tolerance mechanisms working at the cellular level, and the plasma membrane (PM) is believed to be one facet of the cellular mechanisms. The responses of the PM transport proteins to salinity in contrasting species/cultivars were discussed. The review provides a comprehensive overview of the recent advances describing the crucial roles that the PM transport systems have in plant adaptation to salt. Several lines of evidence were presented to demonstrate the correlation between the PM transport proteins and adaptation of plants to high salinity. How alterations in these transport systems of the PM allow plants to cope with the salt stress was also addressed. Although inconsistencies exist in some of the information related to the responses of the PM transport proteins to salinity in different species/cultivars, their key roles in adaptation of plants to high salinity is obvious and evident, and cannot be precluded. Despite the promising results, detailed investigations at the cellular/molecular level are needed in some issues of the PM transport systems in response to salinity to further evaluate their implication in salt tolerance.
Collapse
|
35
|
Morgan SH, Maity PJ, Geilfus CM, Lindberg S, Mühling KH. Leaf ion homeostasis and plasma membrane H(+)-ATPase activity in Vicia faba change after extra calcium and potassium supply under salinity. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2014; 82:244-53. [PMID: 25010036 DOI: 10.1016/j.plaphy.2014.06.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 06/17/2014] [Indexed: 05/15/2023]
Abstract
Salt stress in plants impacts apoplastic ion activities and cytosolic ionic homeostasis. The ameliorating effects exerted by calcium or potassium on compartmentation of ions in leaves under salinity are not fully understood. To clarify how calcium or potassium supply could ameliorate ion homeostasis and ATPase activities under salinity, 5 mM CaSO4 or 10 mM K2SO4 were added with, or without, 100 mM NaCl for 7 d and 21 d to Vicia faba grown in hydroponics. The apoplastic pH was detected with Oregon Green dextran dye in intact second-uppermost leaves by microscopy-based ratio imaging. The cytosolic Ca(2+), Na(+), K(+) activities and pH were detected in protoplasts loaded with the acetoxy methyl-esters of Fura-2, SBFI, PBFI and BCECF, respectively, using epi-fluorescence microscopy. Furthermore, total Ca(2+), Na(+), K(+) concentrations and growth parameters were investigated. The ATPase hydrolyzing activity increased with time, but decreased after long salinity treatment. The activity largely increased in calcium-treated plants, but was depressed in potassium-treated plants after 7 d. The calcium supply increased Vmax, and the ATPase activity increased with salinity in a non-competitive way for 7 d and 21 d. The potassium supply instead decreased activity competitively with Na(+), after 21 d of salinity, with different effects on Km and Vmax. The confirmed higher ATPase activity was related with apoplast acidification, cytosol alkalinization and low cytosolic [Na(+)], and thus, might be an explanation why extra calcium improved shoot and leaf growth.
Collapse
Affiliation(s)
- Sherif H Morgan
- Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-106 91 Stockholm, Sweden; Institute of Plant Nutrition and Soil Science, Kiel University, Hermann Rodewald Strasse 2, D-24118 Kiel, Germany; Plant Physiology Section, Plant Botany Department, Faculty of Agriculture, Cairo University, 12613 Giza, Egypt.
| | - Pooja Jha Maity
- Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-106 91 Stockholm, Sweden.
| | - Christoph-Martin Geilfus
- Institute of Plant Nutrition and Soil Science, Kiel University, Hermann Rodewald Strasse 2, D-24118 Kiel, Germany.
| | - Sylvia Lindberg
- Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-106 91 Stockholm, Sweden.
| | - Karl Hermann Mühling
- Institute of Plant Nutrition and Soil Science, Kiel University, Hermann Rodewald Strasse 2, D-24118 Kiel, Germany.
| |
Collapse
|
36
|
Comparative proteomic analysis reveals molecular mechanism of seedling roots of different salt tolerant soybean genotypes in responses to salinity stress. EUPA OPEN PROTEOMICS 2014. [DOI: 10.1016/j.euprot.2014.05.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
37
|
Wang TT, Ren ZJ, Liu ZQ, Feng X, Guo RQ, Li BG, Li LG, Jing HC. SbHKT1;4, a member of the high-affinity potassium transporter gene family from Sorghum bicolor, functions to maintain optimal Na⁺ /K⁺ balance under Na⁺ stress. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2014; 56:315-32. [PMID: 24325391 DOI: 10.1111/jipb.12144] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 11/26/2013] [Indexed: 05/04/2023]
Abstract
In halophytic plants, the high-affinity potassium transporter HKT gene family can selectively uptake K⁺ in the presence of toxic concentrations of Na⁺. This has so far not been well examined in glycophytic crops. Here, we report the characterization of SbHKT1;4, a member of the HKT gene family from Sorghum bicolor. Upon Na⁺ stress, SbHKT1;4 expression was more strongly upregulated in salt-tolerant sorghum accession, correlating with a better balanced Na⁺ /K⁺ ratio and enhanced plant growth. Heterogeneous expression analyses in mutants of Saccharomyces cerevisiae and Arabidopsis thaliana indicated that overexpressing SbHKT1;4 resulted in hypersensitivity to Na⁺ stress, and such hypersensitivity could be alleviated with the supply of elevated levels of K⁺, implicating that SbHKT1;4 may mediate K⁺ uptake in the presence of excessive Na⁺. Further electrophysiological evidence demonstrated that SbHKT1;4 could transport Na⁺ and K⁺ when expressed in Xenopus laevis oocytes. The relevance of the finding that SbHKT1;4 functions to maintain optimal Na⁺ /K⁺ balance under Na⁺ stress to the breeding of salt-tolerant glycophytic crops is discussed.
Collapse
Affiliation(s)
- Tian-Tian Wang
- Key Laboratory of Plant Resources, Institute of Botany, the Chinese Academy of Sciences, Beijing, 100093, China
| | | | | | | | | | | | | | | |
Collapse
|
38
|
Daptomycin exerts rapid bactericidal activity against Bacillus anthracis without disrupting membrane integrity. Acta Pharmacol Sin 2014; 35:211-8. [PMID: 24362329 DOI: 10.1038/aps.2013.159] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2013] [Accepted: 09/28/2013] [Indexed: 12/29/2022] Open
Abstract
AIM To examine whether the novel cyclic lipopeptide antibiotic daptomycin could be used to treat anthrax and to study the mechanisms underlying its bactericidal action against Bacillus anthracis. METHODS Spore-forming B anthracis AP422 was tested. MIC values of antibiotics were determined. Cell membrane potential was measured using flow cytometric assays with membrane potential-sensitive fluorescent dyes. Cell membrane integrity was detected using To-Pro-3 iodide staining and transmission electron microscopy. K(+) efflux and Na(+) influx were measured using the fluorescent probes PBFI and SBFI-AM, respectively. RESULTS Daptomycin exhibited rapid bactericidal activity against vegetative B anthracis with a MIC value of 0.78 μg/mL, which was comparable to those of ciprofloxacin and penicillin G. Furthermore, daptomycin prevented the germinated spores from growing into vegetative bacteria. Daptomycin concentration-dependently dissipated the membrane potential of B anthracis and caused K(+) efflux and Na(+) influx without disrupting membrane integrity. In contrast, both ciprofloxacin and penicillin G did not change the membrane potential of vegetative bacteria or spores. Penicillin G disrupted membrane integrity of B anthracis, whereas ciprofloxacin had no such effect. CONCLUSION Daptomycin exerts rapid bactericidal action against B anthracis via reducing membrane potential without disrupting membrane integrity. This antibiotic can be used as an alternate therapy for B anthracis infections.
Collapse
|
39
|
Gao HJ, Yang HY, Bai JP, Liang XY, Lou Y, Zhang JL, Wang D, Zhang JL, Niu SQ, Chen YL. Ultrastructural and physiological responses of potato (Solanum tuberosum L.) plantlets to gradient saline stress. FRONTIERS IN PLANT SCIENCE 2014; 5:787. [PMID: 25628634 PMCID: PMC4292236 DOI: 10.3389/fpls.2014.00787] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 12/18/2014] [Indexed: 05/21/2023]
Abstract
Salinity is one of the major abiotic stresses that impacts plant growth and reduces the productivity of field crops. Compared to field plants, test tube plantlets offer a direct and fast approach to investigate the mechanism of salt tolerance. Here we examined the ultrastructural and physiological responses of potato (Solanum tuberosum L. c.v. "Longshu No. 3") plantlets to gradient saline stress (0, 25, 50, 100, and 200 mM NaCl) with two consequent observations (2 and 6 weeks, respectively). The results showed that, with the increase of external NaCl concentration and the duration of treatments, (1) the number of chloroplasts and cell intercellular spaces markedly decreased, (2) cell walls were thickened and even ruptured, (3) mesophyll cells and chloroplasts were gradually damaged to a complete disorganization containing more starch, (4) leaf Na and Cl contents increased while leaf K content decreased, (5) leaf proline content and the activities of catalase (CAT) and superoxide dismutase (SOD) increased significantly, and (6) leaf malondialdehyde (MDA) content increased significantly and stomatal area and chlorophyll content decline were also detected. Severe salt stress (200 mM NaCl) inhibited plantlet growth. These results indicated that potato plantlets adapt to salt stress to some extent through accumulating osmoprotectants, such as proline, increasing the activities of antioxidant enzymes, such as CAT and SOD. The outcomes of this study provide ultrastructural and physiological insights into characterizing potential damages induced by salt stress for selecting salt-tolerant potato cultivars.
Collapse
Affiliation(s)
- Hui-Juan Gao
- Gansu Key Laboratories of Crop Genetic and Germplasm Enhancement and Aridland Crop Science, College of Agronomy, Gansu Agricultural UniversityLanzhou, China
| | - Hong-Yu Yang
- Gansu Key Laboratories of Crop Genetic and Germplasm Enhancement and Aridland Crop Science, College of Agronomy, Gansu Agricultural UniversityLanzhou, China
| | - Jiang-Ping Bai
- Gansu Key Laboratories of Crop Genetic and Germplasm Enhancement and Aridland Crop Science, College of Agronomy, Gansu Agricultural UniversityLanzhou, China
| | - Xin-Yue Liang
- Department of Chemistry, School of Chemistry and Chemical Engineering, Nanjing UniversityNanjing, China
| | - Yan Lou
- Gansu Key Laboratories of Crop Genetic and Germplasm Enhancement and Aridland Crop Science, College of Agronomy, Gansu Agricultural UniversityLanzhou, China
| | - Jun-Lian Zhang
- Gansu Key Laboratories of Crop Genetic and Germplasm Enhancement and Aridland Crop Science, College of Agronomy, Gansu Agricultural UniversityLanzhou, China
| | - Di Wang
- Gansu Key Laboratories of Crop Genetic and Germplasm Enhancement and Aridland Crop Science, College of Agronomy, Gansu Agricultural UniversityLanzhou, China
- *Correspondence: Di Wang, Gansu Key Laboratories of Crop Genetic and Germplasm Enhancement and Aridland Crop Science, College of Agronomy, Gansu Agricultural University, 1 Yingmen Village, Anning District, Lanzhou 730070, Gansu, China e-mail:
| | - Jin-Lin Zhang
- State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou UniversityLanzhou, China
- Jin-Lin Zhang, State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, 768 West Jiayuguan Road, Chengguan District, Lanzhou 730020, Gansu, China e-mail:
| | - Shu-Qi Niu
- State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou UniversityLanzhou, China
| | - Ying-Long Chen
- Plant Nutrition and Soil Science and UWA Institute of Agriculture, School of Earth and Environment, The University of Western AustraliaPerth, WA, Australia
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Education, Northwest A&F UniversityYangling, China
| |
Collapse
|
40
|
Morgan SH, Lindberg S, Mühling KH. Calcium supply effects on wheat cultivars differing in salt resistance with special reference to leaf cytosol ion homeostasis. PHYSIOLOGIA PLANTARUM 2013; 149:321-328. [PMID: 23413983 DOI: 10.1111/ppl.12036] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Revised: 01/18/2013] [Accepted: 01/25/2013] [Indexed: 06/01/2023]
Abstract
Salinity causes changes in cytosolic Ca(2+), [Ca(2+)]cyt, Na(+), [Na(+)]cyt and pH, pH cyt , which induce specific reactions and signals. Reactions causing a rebalancing of the physiological homeostasis of the cytosol could result in plant resistance and growth. Two wheat cultivars, Triticum aestivum, Seds1 and Vinjett, were grown in nutrient solution for 7 days under moderate salinity (0 and 50 mM NaCl) with and without extra addition of 5 mM CaSO4 to investigate the seedling-ion homeostasis under salinity. In the leaf protoplasts [Ca(2+) ]cyt, [Na(+)]cyt and pH cyt were detected using acetoxymethyl esters of the ion-specific dyes, Fura 2, SBFI and BCECF, respectively, and fluorescence microscopy. In addition, both cultivars were grown for 3 weeks at 0, 50 and 125 mM NaCl with, or without, extra addition of 5 mM CaSO4 to detect overall Na(+) and Ca(2+) concentrations in leaves and salinity effects on dry weights. In both cultivars, salinity decreased [Ca(2+)]cyt, while at extra Ca(2+) supplied, [Ca(2+)]cyt increased. The [Ca(2+) ]cyt increase was accompanied by increase in the overall Ca(2+) concentrations in leaves and decrease in the overall Na(+) concentration. Moreover, irrespective of Ca(2+) treatment under salinity, the cultivars reacted in different ways; [Na(+) ]cyt significantly increased only in cv. Vinjett, while pH cyt increased only in cv. Seds1. Even at rather high total Na(+) concentrations, the cytosolic concentrations were kept low in both cultivars. It is discussed whether the increase of [Ca(2+)]cyt and pH cyt can contribute to salt tolerance and if the cytosolic changes are due to changes in overall Ca(2+) and Na(+) concentrations.
Collapse
Affiliation(s)
- Sherif H Morgan
- Institute for Plant Nutrition and Soil Science, Christian Albrechts University, Hermann Rodewald Strasse 2, D-24118, Kiel, Germany; Plant Physiology Section, Plant Botany Department, Faculty of Agriculture, Cairo University, 12613, Giza, Egypt
| | | | | |
Collapse
|
41
|
Serra TS, Figueiredo DD, Cordeiro AM, Almeida DM, Lourenço T, Abreu IA, Sebastián A, Fernandes L, Contreras-Moreira B, Oliveira MM, Saibo NJM. OsRMC, a negative regulator of salt stress response in rice, is regulated by two AP2/ERF transcription factors. PLANT MOLECULAR BIOLOGY 2013; 82:439-55. [PMID: 23703395 DOI: 10.1007/s11103-013-0073-9] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 05/13/2013] [Indexed: 05/03/2023]
Abstract
High salinity causes remarkable losses in rice productivity worldwide mainly because it inhibits growth and reduces grain yield. To cope with environmental changes, plants evolved several adaptive mechanisms, which involve the regulation of many stress-responsive genes. Among these, we have chosen OsRMC to study its transcriptional regulation in rice seedlings subjected to high salinity. Its transcription was highly induced by salt treatment and showed a stress-dose-dependent pattern. OsRMC encodes a receptor-like kinase described as a negative regulator of salt stress responses in rice. To investigate how OsRMC is regulated in response to high salinity, a salt-induced rice cDNA expression library was constructed and subsequently screened using the yeast one-hybrid system and the OsRMC promoter as bait. Thereby, two transcription factors (TFs), OsEREBP1 and OsEREBP2, belonging to the AP2/ERF family were identified. Both TFs were shown to bind to the same GCC-like DNA motif in OsRMC promoter and to negatively regulate its gene expression. The identified TFs were characterized regarding their gene expression under different abiotic stress conditions. This study revealed that OsEREBP1 transcript level is not significantly affected by salt, ABA or severe cold (5 °C) and is only slightly regulated by drought and moderate cold. On the other hand, the OsEREBP2 transcript level increased after cold, ABA, drought and high salinity treatments, indicating that OsEREBP2 may play a central role mediating the response to different abiotic stresses. Gene expression analysis in rice varieties with contrasting salt tolerance further suggests that OsEREBP2 is involved in salt stress response in rice.
Collapse
Affiliation(s)
- Tânia S Serra
- Genomics of Plant Stress Laboratory, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Anil VS, Kavitha PG, Kuruvilla S, Kumar P, Mathew MK. Measurements of cytosolic ion concentrations in live cells. Methods Mol Biol 2013; 953:233-41. [PMID: 23073887 DOI: 10.1007/978-1-62703-152-3_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Here, we describe a series of methods suitable for the measurement of cytosolic ion concentrations in living plant cells using ion selective dyes. We describe procedures for the use of SBFI for the measurement of Na(+) in live cells. The resulting material is suitable for most standard cell biology procedures.
Collapse
Affiliation(s)
- Veena S Anil
- Department of (Agri) Biotechnology, College of Agriculture-Hassan, Subcampus of University of Agricultural Sciences, Bangalore, India
| | | | | | | | | |
Collapse
|
43
|
Khan MN, Siddiqui MH, Mohammad F, Naeem M. Interactive role of nitric oxide and calcium chloride in enhancing tolerance to salt stress. Nitric Oxide 2012; 27:210-8. [DOI: 10.1016/j.niox.2012.07.005] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 07/15/2012] [Accepted: 07/20/2012] [Indexed: 10/28/2022]
|
44
|
Horie T, Karahara I, Katsuhara M. Salinity tolerance mechanisms in glycophytes: An overview with the central focus on rice plants. RICE (NEW YORK, N.Y.) 2012; 5:11. [PMID: 27234237 PMCID: PMC5520831 DOI: 10.1186/1939-8433-5-11] [Citation(s) in RCA: 141] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Accepted: 06/22/2012] [Indexed: 05/04/2023]
Abstract
Elevated Na(+) levels in agricultural lands are increasingly becoming a serious threat to the world agriculture. Plants suffer osmotic and ionic stress under high salinity due to the salts accumulated at the outside of roots and those accumulated at the inside of the plant cells, respectively. Mechanisms of salinity tolerance in plants have been extensively studied and in the recent years these studies focus on the function of key enzymes and plant morphological traits. Here, we provide an updated overview of salt tolerant mechanisms in glycophytes with a particular interest in rice (Oryza sativa) plants. Protective mechanisms that prevent water loss due to the increased osmotic pressure, the development of Na(+) toxicity on essential cellular metabolisms, and the movement of ions via the apoplastic pathway (i.e. apoplastic barriers) are described here in detail.
Collapse
Affiliation(s)
- Tomoaki Horie
- Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, 3-15-1, Tokida, Ueda, Nagano, 386-8567 Japan
| | - Ichirou Karahara
- Department of Biology, Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama, 930-8555 Japan
| | - Maki Katsuhara
- Institute of Plant Science and Resources, Okayama University, 20-1, Chuo-2-chome, Kurashiki, Okayama, 710-0046 Japan
| |
Collapse
|
45
|
|
46
|
Fluorescence lifetime imaging (FLIM) measurements in salinity research. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2012. [PMID: 22895757 DOI: 10.1007/978-1-61779-986-0_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
Plant response to salt stress involves changes in intracellular ion concentrations that can be estimated by ion-selective fluorescent dyes. Conventional confocal/fluorescent imaging does not always accurately reflect the process, since it is dependent not only on the ion concentration but on the dye concentration itself. Fluorescent lifetime imaging (FLIM) can resolve this problem: images derived under this technique are based on the fluorescent lifetime distribution of the bound/unbound state of the fluorophore, and not on the fluorescent intensity. On the example of 2'-7'-bis(carboxyethyl)-5(6)-carboxyfluorescein (BCECF) and Ca Green, we demonstrate the potential of FLIM technique in salinity studies.
Collapse
|
47
|
Theerawitaya C, Boriboonkaset T, Cha-um S, Supaibulwatana K, Kirdmanee C. Transcriptional regulations of the genes of starch metabolism and physiological changes in response to salt stress rice (Oryza sativa L.) seedlings. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2012; 18:197-208. [PMID: 23814434 PMCID: PMC3550511 DOI: 10.1007/s12298-012-0114-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The aim of this investigation was to compare the transcriptional expression of starch metabolism, involving genes and physiological characters, in seedlings of two contrasting salt-tolerant rice genotypes, in response to salt-stress. The soluble sugar content in rice seedlings of both salt-tolerant and salt-sensitive genotypes was enriched, relating to starch degradation, in plants subjected to 200 mM NaCl. In the salt-tolerant cultivar Pokkali, a major source of carbon may be that derived from the photosynthetic system and starch degradation. In starch degradation, only Pho and PWD genes in Pokkali were upregulated in plants subjected to salt stress. In contrast, the photosynthetic abilities of IR29 salt-susceptible cultivar dropped significantly, relating to growth reduction. The major source of carbohydrate in salt-stressed seedlings of the IR29 cultivar may be gained from starch metabolism, regulated by ADP-glucose pyrophosphorylase (AGP), starch synthase (SS), starch branching enzyme (SBE), starch debranching enzyme (ISA), glucan-water dikinase (GWD), dispropotionating enzyme (DPE), phospho glucan-water dikinase (PWD) and starch phosphorylase (Pho). Also, the major route of soluble sugar in salt-stressed Pokkali seedlings was derived from photosynthesis and starch metabolism. This was identified as novel information in the present study.
Collapse
Affiliation(s)
- Cattarin Theerawitaya
- />National Center for Genetic Engineering and Biotechnology, 113 Paholyothin Rd., Klong 1, Klong Luang, Pathumthani 12120 Thailand
| | - Thanapol Boriboonkaset
- />Department of Biotechnology, Faculty of Science, Mahidol University, Payathai, Bangkok 10400 Thailand
| | - Suriyan Cha-um
- />National Center for Genetic Engineering and Biotechnology, 113 Paholyothin Rd., Klong 1, Klong Luang, Pathumthani 12120 Thailand
| | - Kanyaratt Supaibulwatana
- />Department of Biotechnology, Faculty of Science, Mahidol University, Payathai, Bangkok 10400 Thailand
| | - Chalermpol Kirdmanee
- />National Center for Genetic Engineering and Biotechnology, 113 Paholyothin Rd., Klong 1, Klong Luang, Pathumthani 12120 Thailand
| |
Collapse
|
48
|
Brini F, Masmoudi K. Ion Transporters and Abiotic Stress Tolerance in Plants. ISRN MOLECULAR BIOLOGY 2012; 2012:927436. [PMID: 27398240 PMCID: PMC4907263 DOI: 10.5402/2012/927436] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 04/10/2012] [Indexed: 11/23/2022]
Abstract
Adaptation of plants to salt stress requires cellular ion homeostasis involving net intracellular Na+ and Cl− uptake and subsequent vacuolar compartmentalization without toxic ion accumulation in the cytosol. Sodium ions can enter the cell through several low- and high-affinity K+ carriers. Some members of the HKT family function as sodium transporter and contribute to Na+ removal from the ascending xylem sap and recirculation from the leaves to the roots via the phloem vasculature. Na+ sequestration into the vacuole depends on expression and activity of Na+/H+ antiporter that is driven by electrochemical gradient of protons generated by the vacuolar H+-ATPase and the H+-pyrophosphatase. Sodium extrusion at the root-soil interface is presumed to be of critical importance for the salt tolerance. Thus, a very rapid efflux of Na+ from roots must occur to control net rates of influx. The Na+/H+ antiporter SOS1 localized to the plasma membrane is the only Na+ efflux protein from plants characterized so far. In this paper, we analyze available data related to ion transporters and plant abiotic stress responses in order to enhance our understanding about how salinity and other abiotic stresses affect the most fundamental processes of cellular function which have a substantial impact on plant growth development.
Collapse
Affiliation(s)
- Faïçal Brini
- Plant Protection and Improvement Laboratory, Centre of Biotechnology of Sfax (CBS), University of Sfax, P.O. Box 1177, 3018 Sfax, Tunisia
| | - Khaled Masmoudi
- Plant Protection and Improvement Laboratory, Centre of Biotechnology of Sfax (CBS), University of Sfax, P.O. Box 1177, 3018 Sfax, Tunisia
| |
Collapse
|
49
|
Kavitha PG, Miller AJ, Mathew MK, Maathuis FJM. Rice cultivars with differing salt tolerance contain similar cation channels in their root cells. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:3289-96. [PMID: 22345644 PMCID: PMC3350936 DOI: 10.1093/jxb/ers052] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Revised: 01/30/2012] [Accepted: 02/01/2012] [Indexed: 05/10/2023]
Abstract
Salinity poses a major threat for agriculture worldwide. Rice is one of the major crops where most of the high-yielding cultivars are highly sensitive to salinity. Several studies on the genetic variability across rice cultivars suggest that the activity and composition of root plasma membrane transporters could underlie the observed cultivar-specific salinity tolerance in rice. In the current study, it was found that the salt-tolerant cultivar Pokkali maintains a higher K+/Na+ ratio compared with the salt-sensitive IR20 in roots as well as in shoots. Using Na+ reporter dyes, IR20 root protoplasts showed a much faster Na+ accumulation than Pokkali protoplasts. Membrane potential measurements showed that root cells exposed to Na+ in IR20 depolarized considerably further than those of Pokkali. These results suggest that IR20 has a larger plasma membrane Na+ conductance. To assess whether this could be due to different ion channel properties, root protoplasts from both Pokkali and IR20 rice cultivars were patch-clamped. Voltage-dependent K+ inward rectifiers, K+ outward rectifiers, and voltage-independent, non-selective channels with unitary conductances of around 35, 40, and 10 pS, respectively, were identified. Only the non-selective channel showed significant Na+ permeability. Intriguingly, in both cultivars, the activity of the K+ inward rectifier was drastically down-regulated after plant growth in salt but gating, conductance, and activity of all channel types were very similar for the two cultivars.
Collapse
Affiliation(s)
- P. G. Kavitha
- Membrane Biophysics Group, National Centre for Biological Sciences, University of Agricultural Sciences-G.K.V.K Campus, Bellary Road, Bangalore, India
| | - A. J. Miller
- Department of Disease and Stress Biology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - M. K. Mathew
- Membrane Biophysics Group, National Centre for Biological Sciences, University of Agricultural Sciences-G.K.V.K Campus, Bellary Road, Bangalore, India
| | | |
Collapse
|
50
|
Schulze LM, Britto DT, Li M, Kronzucker HJ. A pharmacological analysis of high-affinity sodium transport in barley (Hordeum vulgare L.): a 24Na+/42K+ study. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:2479-89. [PMID: 22268152 PMCID: PMC3346217 DOI: 10.1093/jxb/err419] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Revised: 11/21/2011] [Accepted: 11/23/2011] [Indexed: 05/19/2023]
Abstract
Soil sodium, while toxic to most plants at high concentrations, can be beneficial at low concentrations, particularly when potassium is limiting. However, little is known about Na(+) uptake in this 'high-affinity' range. New information is provided here with an insight into the transport characteristics, mechanism, and ecological significance of this phenomenon. High-affinity Na(+) and K(+) fluxes were investigated using the short-lived radiotracers (24)Na and (42)K, under an extensive range of measuring conditions (variations in external sodium, and in nutritional and pharmacological agents). This work was supported by electrophysiological, compartmental, and growth analyses. Na(+) uptake was extremely sensitive to all treatments, displaying properties of high-affinity K(+) transporters, K(+) channels, animal Na(+) channels, and non-selective cation channels. K(+), NH(4)(+), and Ca(2+) suppressed Na(+) transport biphasically, yielding IC(50) values of 30, 10, and <5 μM, respectively. Reciprocal experiments showed that K(+) influx is neither inhibited nor stimulated by Na(+). Sodium efflux constituted 65% of influx, indicating a futile cycle. The thermodynamic feasibility of passive channel mediation is supported by compartmentation and electrophysiological data. Our study complements recent advances in the molecular biology of high-affinity Na(+) transport by uncovering new physiological foundations for this transport phenomenon, while questioning its ecological relevance.
Collapse
Affiliation(s)
| | | | | | - Herbert J. Kronzucker
- Department of Biological Sciences, University of Toronto, 1265 Military Trail, Toronto, ON, Canada M1C 1A4
| |
Collapse
|