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Liu X, Elzenga JTM, Venema JH, Tiedge KJ. Thriving in a salty future: morpho-anatomical, physiological and molecular adaptations to salt stress in alfalfa (Medicago sativa L.) and other crops. ANNALS OF BOTANY 2024; 134:1113-1130. [PMID: 39215647 PMCID: PMC11688534 DOI: 10.1093/aob/mcae152] [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: 05/17/2024] [Accepted: 08/29/2024] [Indexed: 09/04/2024]
Abstract
BACKGROUND With soil salinity levels rising at an alarming rate, accelerated by climate change and human interventions, there is a growing need for crop varieties that can grow on saline soils. Alfalfa (Medicago sativa) is a cool-season perennial leguminous crop, commonly grown as forage, biofuel feedstock and soil conditioner. It demonstrates significant potential for agricultural circularity and sustainability, for example by fixing nitrogen, sequestering carbon and improving soil structures. Although alfalfa is traditionally regarded as a moderately salt-tolerant species, modern alfalfa varieties display specific salt-tolerance mechanisms, which could be used to pave its role as a leading crop able to grow on saline soils. SCOPE Alfalfa's salt tolerance underlies a large variety of cascading biochemical and physiological mechanisms. These are partly enabled by its complex genome structure and out-crossing nature, but which entail impediments for molecular and genetic studies. This review first summarizes the general effects of salinity on plants and the broad-ranging mechanisms for dealing with salt-induced osmotic stress, ion toxicity and secondary stress. Second, we address the defensive and adaptive strategies that have been described for alfalfa, such as the plasticity of alfalfa's root system, hormonal crosstalk for maintaining ion homeostasis, spatiotemporal specialized metabolite profiles and the protection of alfalfa-rhizobia associations. Finally, bottlenecks for research of the physiological and molecular salt-stress responses as well as biotechnology-driven improvements of salt tolerance are identified and discussed. CONCLUSION Understanding morpho-anatomical, physiological and molecular responses to salinity is essential for the improvement of alfalfa and other crops in saline land reclamation. This review identifies potential breeding targets for enhancing the stability of alfalfa performance and general crop robustness for rising salt levels as well as to promote alfalfa applications in saline land management.
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Affiliation(s)
- Xu Liu
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - J Theo M Elzenga
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Jan Henk Venema
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Kira J Tiedge
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
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2
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Lee S, Hwang I. The long non-coding RNA CARMA directs sucrose-responsive osmoregulation. MOLECULAR PLANT 2024; 17:1803-1804. [PMID: 39533711 DOI: 10.1016/j.molp.2024.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2024] [Revised: 11/11/2024] [Accepted: 11/11/2024] [Indexed: 11/16/2024]
Affiliation(s)
- Seungchul Lee
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Ildoo Hwang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Republic of Korea; Institute for Convergence Research and Education in Advanced Technology, Yonsei University, Incheon 21983, Republic of Korea.
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3
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Zhang Z, Luo X, Friess DA, Wang S, Li Y, Li Y. Stronger increases but greater variability in global mangrove productivity compared to that of adjacent terrestrial forests. Nat Ecol Evol 2024; 8:239-250. [PMID: 38172286 DOI: 10.1038/s41559-023-02264-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 10/31/2023] [Indexed: 01/05/2024]
Abstract
Mangrove forests are a highly productive ecosystem with important potential to offset anthropogenic greenhouse gas emissions. Mangroves are expected to respond differently to climate change compared to terrestrial forests owing to their location in the tidal environment and unique ecophysiological characteristics, but the magnitude of difference remains uncertain at the global scale. Here we use satellite observations to examine mean trends and interannual variability in the productivity of global mangrove forests and nearby terrestrial evergreen broadleaf forests from 2001 to 2020. Although both types of ecosystem experienced significant recent increases in productivity, mangroves exhibited a stronger increasing trend and greater interannual variability in productivity than evergreen broadleaf forests on three-quarters of their co-occurring coasts. The difference in productivity trends is attributed to the stronger CO2 fertilization effect on mangrove photosynthesis, while the discrepancy in interannual variability is attributed to the higher sensitivities to variations in precipitation and sea level. Our results indicate that mangroves will have a faster increase in productivity than terrestrial forests in a CO2-rich future but may suffer more from deficits in water availability, highlighting a key difference between terrestrial and tidal ecosystems in their responses to climate change.
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Affiliation(s)
- Zhen Zhang
- State Key Laboratory of Marine Environmental Science, Key Laboratory of Coastal and Wetland Ecosystems (Ministry of Education), College of the Environment and Ecology, Xiamen University, Xiamen, China
- Department of Geography, National University of Singapore, Singapore, Singapore
| | - Xiangzhong Luo
- Department of Geography, National University of Singapore, Singapore, Singapore.
- Center for Nature-Based Climate Solutions, National University of Singapore, Singapore, Singapore.
| | - Daniel A Friess
- Department of Earth and Environmental Sciences, Tulane University, New Orleans, LA, USA
| | - Songhan Wang
- Jiangsu Collaborative Innovation Center for Modern Crop Production/Key Laboratory of Crop Physiology and Ecology in Southern China, Nanjing Agricultural University, Nanjing, China
| | - Yi Li
- State Key Laboratory of Marine Environmental Science, Key Laboratory of Coastal and Wetland Ecosystems (Ministry of Education), College of the Environment and Ecology, Xiamen University, Xiamen, China
| | - Yangfan Li
- State Key Laboratory of Marine Environmental Science, Key Laboratory of Coastal and Wetland Ecosystems (Ministry of Education), College of the Environment and Ecology, Xiamen University, Xiamen, China.
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4
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Ding J, McDowell N, Fang Y, Ward N, Kirwan ML, Regier P, Megonigal P, Zhang P, Zhang H, Wang W, Li W, Pennington SC, Wilson SJ, Stearns A, Bailey V. Modeling the mechanisms of conifer mortality under seawater exposure. THE NEW PHYTOLOGIST 2023. [PMID: 37376720 DOI: 10.1111/nph.19076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 05/26/2023] [Indexed: 06/29/2023]
Abstract
Relative sea level rise (SLR) increasingly impacts coastal ecosystems through the formation of ghost forests. To predict the future of coastal ecosystems under SLR and changing climate, it is important to understand the physiological mechanisms underlying coastal tree mortality and to integrate this knowledge into dynamic vegetation models. We incorporate the physiological effect of salinity and hypoxia in a dynamic vegetation model in the Earth system land model, and used the model to investigate the mechanisms of mortality of conifer forests on the west and east coast sites of USA, where trees experience different form of sea water exposure. Simulations suggest similar physiological mechanisms can result in different mortality patterns. At the east coast site that experienced severe increases in seawater exposure, trees loose photosynthetic capacity and roots rapidly, and both storage carbon and hydraulic conductance decrease significantly within a year. Over time, further consumption of storage carbon that leads to carbon starvation dominates mortality. At the west coast site that gradually exposed to seawater through SLR, hydraulic failure dominates mortality because root loss impacts on conductance are greater than the degree of storage carbon depletion. Measurements and modeling focused on understanding the physiological mechanisms of mortality is critical to reducing predictive uncertainty.
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Affiliation(s)
- Junyan Ding
- Biological Sciences Division, Pacific Northwest National Lab, PO Box 999, Richland, WA, 99352, USA
| | - Nate McDowell
- Biological Sciences Division, Pacific Northwest National Lab, PO Box 999, Richland, WA, 99352, USA
- School of Biological Sciences, Washington State University, PO Box 644236, Pullman, WA, 99164-4236, USA
| | - Yilin Fang
- Earth Systems Science Division, Pacific Northwest National Lab, Richland, WA, 99352, USA
| | - Nicholas Ward
- Marine and Coastal Research Laboratory, Pacific Northwest National Laboratory, Sequim, WA, 98382, USA
| | - Matthew L Kirwan
- Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, VA, 23062, USA
| | - Peter Regier
- Marine and Coastal Research Laboratory, Pacific Northwest National Laboratory, Sequim, WA, 98382, USA
| | - Patrick Megonigal
- Smithsonian Environmental Research Center, Edgewater, MD, 21037, USA
| | - Peipei Zhang
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China
| | - Hongxia Zhang
- Shapotou Desert Research and Experiment Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Wenzhi Wang
- The Key Laboratory of Mountain Environment Evolution and Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, 610041, China
| | - Weibin Li
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730020, China
| | - Stephanie C Pennington
- Joint Global Change Research Institute, Pacific Northwest National Laboratory, College Park, MD, 20740, USA
| | | | - Alice Stearns
- Smithsonian Environmental Research Center, Edgewater, MD, 21037, USA
| | - Vanessa Bailey
- Biological Sciences Division, Pacific Northwest National Lab, PO Box 999, Richland, WA, 99352, USA
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5
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Feng X, Lu Y, Jiang M, Katul G, Manzoni S, Mrad A, Vico G. Instantaneous stomatal optimization results in suboptimal carbon gain due to legacy effects. PLANT, CELL & ENVIRONMENT 2022; 45:3189-3204. [PMID: 36030546 DOI: 10.1111/pce.14427] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 08/15/2022] [Accepted: 08/22/2022] [Indexed: 06/15/2023]
Affiliation(s)
- Xue Feng
- Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Minneapolis, Minnesota, USA
- Saint Anthony Falls Laboratory, University of Minnesota, Minneapolis, Minnesota, USA
| | - Yaojie Lu
- Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Minneapolis, Minnesota, USA
| | - Mingkai Jiang
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Gabriel Katul
- Department of Civil and Environmental Engineering, Duke University, Durham, North Carolina, USA
| | - Stefano Manzoni
- Department of Physical Geography and Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden
| | - Assaad Mrad
- Department of Civil and Environmental Engineering, University of California, Irvine, California, USA
- Department of Engineering, Wake Forest University, Winston-Salem, North Carolina, USA
| | - Giulia Vico
- Department of Crop Production Ecology, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden
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6
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Mijiti M, Wang Y, Wang L, Habuding X. Tamarix hispida NAC Transcription Factor ThNAC4 Confers Salt and Drought Stress Tolerance to Transgenic Tamarix and Arabidopsis. PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11192647. [PMID: 36235512 PMCID: PMC9570625 DOI: 10.3390/plants11192647] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 09/18/2022] [Accepted: 10/04/2022] [Indexed: 06/12/2023]
Abstract
Salt and drought are considered two major abiotic stresses that have a significant impact on plants. Plant NAC (NAM, ATAF1/2, and CUC2) transcription factors (TFs) have been shown to play vital roles in plant development and responses to various abiotic stresses. ThNAC4, a NAC gene from Tamarix hispida involved in salt and osmotic stress tolerance, was identified and characterized in this study. According to a phylogenetic study, ThNAC4 is a member of NAC subfamily II. Subcellular localization analysis showed that ThNAC4 is located in the nucleus, and transcriptional activation experiments demonstrated that ThNAC4 is a transcriptional activator. Transgenic Arabidopsis plants overexpressing ThNAC4 exhibited improved salt and osmotic tolerance, as demonstrated by improved physiological traits. ThNAC4-overexpressing and ThNAC4-silenced T. hispida plants were generated using the transient transformation method and selected for gain- and loss-of-function analysis. The results showed that overexpression of ThNAC4 in transgenic Tamarix and Arabidopsis plants increased the activities of antioxidant enzymes (SOD, POD, and GST) and osmoprotectant (proline and trehalose) contents under stress conditions. These findings suggest that ThNAC4 plays an important physiological role in plant abiotic stress tolerance by increasing ROS scavenging ability and improving osmotic potential.
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Affiliation(s)
- Meiheriguli Mijiti
- Xinjiang Key Laboratory of Special Species Conservation and Regulatory Biology, Key Laboratory of Special Environment Biodiversity Application and Regulation in Xinjiang, Key Laboratory of Plant Stress Biology in Arid Land, College of Life Science, Xinjiang Normal University, Urumqi 830054, China
| | - Yucheng Wang
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China
| | - Liuqiang Wang
- State Key Laboratory of Tree Genetics and Breeding, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China
| | - Xugela Habuding
- Xinjiang Key Laboratory of Special Species Conservation and Regulatory Biology, Key Laboratory of Special Environment Biodiversity Application and Regulation in Xinjiang, Key Laboratory of Plant Stress Biology in Arid Land, College of Life Science, Xinjiang Normal University, Urumqi 830054, China
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7
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McDowell NG, Ball M, Bond‐Lamberty B, Kirwan ML, Krauss KW, Megonigal JP, Mencuccini M, Ward ND, Weintraub MN, Bailey V. Processes and mechanisms of coastal woody-plant mortality. GLOBAL CHANGE BIOLOGY 2022; 28:5881-5900. [PMID: 35689431 PMCID: PMC9544010 DOI: 10.1111/gcb.16297] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Accepted: 05/24/2022] [Indexed: 05/26/2023]
Abstract
Observations of woody plant mortality in coastal ecosystems are globally widespread, but the overarching processes and underlying mechanisms are poorly understood. This knowledge deficiency, combined with rapidly changing water levels, storm surges, atmospheric CO2 , and vapor pressure deficit, creates large predictive uncertainty regarding how coastal ecosystems will respond to global change. Here, we synthesize the literature on the mechanisms that underlie coastal woody-plant mortality, with the goal of producing a testable hypothesis framework. The key emergent mechanisms underlying mortality include hypoxic, osmotic, and ionic-driven reductions in whole-plant hydraulic conductance and photosynthesis that ultimately drive the coupled processes of hydraulic failure and carbon starvation. The relative importance of these processes in driving mortality, their order of progression, and their degree of coupling depends on the characteristics of the anomalous water exposure, on topographic effects, and on taxa-specific variation in traits and trait acclimation. Greater inundation exposure could accelerate mortality globally; however, the interaction of changing inundation exposure with elevated CO2 , drought, and rising vapor pressure deficit could influence mortality likelihood. Models of coastal forests that incorporate the frequency and duration of inundation, the role of climatic drivers, and the processes of hydraulic failure and carbon starvation can yield improved estimates of inundation-induced woody-plant mortality.
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Affiliation(s)
- Nate G. McDowell
- Atmospheric Sciences and Global Change DivisionPacific Northwest National LabRichlandWashingtonUSA
- School of Biological SciencesWashington State UniversityPullmanWashingtonUSA
| | - Marilyn Ball
- Plant Science Division, Research School of BiologyThe Australian National UniversityActonAustralian Capital TerritoryAustralia
| | - Ben Bond‐Lamberty
- Joint Global Change Research Institute, Pacific Northwest National LaboratoryCollege ParkMarylandUSA
| | - Matthew L. Kirwan
- Virginia Institute of Marine Science, William & MaryGloucester PointVirginiaUSA
| | - Ken W. Krauss
- U.S. Geological Survey, Wetland and Aquatic Research CenterLafayetteLouisianaUSA
| | | | - Maurizio Mencuccini
- ICREA, Passeig Lluís Companys 23BarcelonaSpain
- CREAFCampus UAB, BellaterraBarcelonaSpain
| | - Nicholas D. Ward
- Marine and Coastal Research LaboratoryPacific Northwest National LaboratorySequimWashingtonUSA
- School of OceanographyUniversity of WashingtonSeattleWashingtonUSA
| | - Michael N. Weintraub
- Department of Environmental SciencesUniversity of ToledoToledoOhioUSA
- Biological Sciences DivisionPacific Northwest National LaboratoryWashingtonUSA
| | - Vanessa Bailey
- Biological Sciences DivisionPacific Northwest National LaboratoryWashingtonUSA
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8
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Li W, Zhang H, Wang W, Zhang P, Ward ND, Norwood M, Myers-Pigg A, Zhao C, Leff R, Yabusaki S, Waichler S, Bailey VL, McDowell NG. Changes in carbon and nitrogen metabolism during seawater-induced mortality of Picea sitchensis trees. TREE PHYSIOLOGY 2021; 41:2326-2340. [PMID: 34014270 DOI: 10.1093/treephys/tpab073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 05/13/2021] [Indexed: 05/13/2023]
Abstract
Increasing seawater exposure is causing mortality of coastal forests, yet the physiological response associated with seawater-induced tree mortality, particularly in non-halophytes, is poorly understood. We investigated the shifts in carbon and nitrogen (N) metabolism of mature Sitka-spruce trees that were dying after an ecosystem-scale manipulation of tidal seawater exposure. Soil porewater salinity and foliar ion concentrations increased after seawater exposure and were strongly correlated with the percentage of live foliated crown (PLFC; e.g., crown 'greenness', a measure of progression to death). Co-occurring with decreasing PLFC was decreasing photosynthetic capacity, N-investment into photosynthesis, N-resorption efficiency and non-structural carbohydrate (soluble sugars and starch) concentrations, with the starch reserves depleted to near zero when PLFC dropped below 5%. Combined with declining PLFC, these changes subsequently decreased total carbon gain and thus exacerbated the carbon starvation process. This study suggests that an impairment in carbon and N metabolism during the mortality process after seawater exposure is associated with the process of carbon starvation, and provides critical knowledge necessary to predict sea-level rise impacts on coastal forests.
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Affiliation(s)
- Weibin Li
- State Key Laboratory of Grassland and Agro-ecosystems, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China
- Atmospheric Sciences & Global Change Division, Pacific Northwest National Laboratory, Richland, Washington 99354, USA
- Key Laboratory of Geospatial Technology for Middle and Lower Yellow River Regions (Henan University), Ministry of Education, Kaifeng 475004, China
| | - Hongxia Zhang
- Atmospheric Sciences & Global Change Division, Pacific Northwest National Laboratory, Richland, Washington 99354, USA
- Shapotou Desert Research and Experiment Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Wenzhi Wang
- Atmospheric Sciences & Global Change Division, Pacific Northwest National Laboratory, Richland, Washington 99354, USA
| | - Peipei Zhang
- Atmospheric Sciences & Global Change Division, Pacific Northwest National Laboratory, Richland, Washington 99354, USA
- School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Nicholas D Ward
- Marine and Coastal Research Laboratory, Pacific Northwest National Laboratory, Sequim, Washington 98382, USA
- School of Oceanography, University of Washington, Seattle, Washington 98195, USA
| | - Matt Norwood
- Marine and Coastal Research Laboratory, Pacific Northwest National Laboratory, Sequim, Washington 98382, USA
| | - Allison Myers-Pigg
- Marine and Coastal Research Laboratory, Pacific Northwest National Laboratory, Sequim, Washington 98382, USA
| | - Chuanyan Zhao
- State Key Laboratory of Grassland and Agro-ecosystems, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China
| | - Riley Leff
- Atmospheric Sciences & Global Change Division, Pacific Northwest National Laboratory, Richland, Washington 99354, USA
| | - Steve Yabusaki
- Earth Systems Science, Pacific Northwest National Laboratory, Richland, Washington 99354, USA
| | - Scott Waichler
- Earth Systems Science, Pacific Northwest National Laboratory, Richland, Washington 99354, USA
| | - Vanessa L Bailey
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99354, USA
| | - Nate G McDowell
- Atmospheric Sciences & Global Change Division, Pacific Northwest National Laboratory, Richland, Washington 99354, USA
- School of Biological Sciences, Washington State University, Pullman, Washington 99164-4236, USA
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9
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Navarro-León E, Paradisone V, López-Moreno FJ, Rios JJ, Esposito S, Blasco B. Effect of CAX1a TILLING mutations on photosynthesis performance in salt-stressed Brassica rapa plants. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2021; 311:111013. [PMID: 34482916 DOI: 10.1016/j.plantsci.2021.111013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 07/25/2021] [Accepted: 08/02/2021] [Indexed: 06/13/2023]
Abstract
Salinity is an important environmental factor that reduces plant productivity in many world regions. It affects negatively photosynthesis causing a growth reduction. Likewise, calcium (Ca2+) is crucial in plant stress response. Therefore, the modification of Ca2+ cation exchangers (CAX) transporters could be a potential strategy to increase plant tolerance to salinity. Using Targeting Induced Local Lesions in Genomes (TILLING), researchers generated three mutants of Brassica rapa CAX1a transporter: BraA.cax1a-7, BraA.cax1a-4, and BraA.cax1a-12. The aim of this study was to test the effect of those mutations on salt tolerance focusing on the response to the photosynthesis process. Thus, the three BraA.cax1a mutants and the parental line (R-o-18) were grown under salinity conditions, and parameters related to biomass, photosynthesis performance, glucose-6-phosphate dehydrogenase (G6PDH, EC 1.1.1.49), and soluble carbohydrates were measured. BraA.cax1a-4 provided higher biomass and a better photosynthetic performance manifested by higher water use efficiency (WUE), Fv/Fm, electron fluxes, and Rubisco (EC 4.1.1.39) values. In addition, BraA.cax1a-4 presented increased osmotic protection through myo-inositol accumulation. On the other hand, BraA.cax1a-7 produced some negative effects on photosynthesis performance and lower G6PDH and Rubisco accumulations. Therefore, this study points out BraA.cax1a-4 as a useful mutation to improve photosynthetic performance in plants grown under saline conditions.
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Affiliation(s)
- Eloy Navarro-León
- Department of Plant Physiology, Faculty of Sciences, University of Granada, 18071, Granada, Spain.
| | - Valeria Paradisone
- Dipartimento di Biologia, Università di Napoli "Federico II", Complesso Universitario di Monte Sant'Angelo, Via Cinthia, 80126, Napoli, Italy.
| | | | - Juan José Rios
- Department of Plant Physiology, Faculty of Sciences, University of Granada, 18071, Granada, Spain.
| | - Sergio Esposito
- Dipartimento di Biologia, Università di Napoli "Federico II", Complesso Universitario di Monte Sant'Angelo, Via Cinthia, 80126, Napoli, Italy.
| | - Begoña Blasco
- Department of Plant Physiology, Faculty of Sciences, University of Granada, 18071, Granada, Spain.
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10
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Coupling Relationship of Leaf Economic and Hydraulic Traits of Alhagisparsifolia Shap. in a Hyper-Arid Desert Ecosystem. PLANTS 2021; 10:plants10091867. [PMID: 34579402 PMCID: PMC8465641 DOI: 10.3390/plants10091867] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 09/05/2021] [Accepted: 09/06/2021] [Indexed: 12/03/2022]
Abstract
In this study, Alhagisparsifolia Shap. was used to test the hypothesis that leaf economic and hydraulic traits are coupled in plants in a hyper-arid region. Five economic traits and six hydraulic traits were examined to explore the relationship. Results showed that the stomatal density (SD) on both surfaces was coupled with maximum stomatal conductance to water vapor (gwmax) and leaf tissue density (TD). SD on adaxial surface (SDaba) was significantly positively related to vein density (VD) but negatively related to leaf thickness (LT) and stomatal length on adaxial surface (SLada). Nitrogen concentration based on mass (Nmass) was significantly negatively correlated with leaf mass per area (LMA), LT, and VD, whereas nitrogen concentration based on area (Narea) was significantly positively related to LMA and TD. Mean annual precipitation (MAP) contributed the most to the changes in LT and stomatal length (SL). Soil salt contributed the most to TD, SD, and gwmax. Soli nutrients influenced the most of LMA and VD. Mean annual temperature contributed the most to Nmass and Narea. In conclusion, the economics of leaves coupled with their hydraulic traits provides an economical and efficient strategy to adapt to the harsh environment in hyper-arid regions.
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11
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Abstract
Shaping global water and carbon cycles, plants lift water from roots to leaves through xylem conduits. The importance of xylem water conduction makes it crucial to understand how natural selection deploys conduit diameters within and across plants. Wider conduits transport more water but are likely more vulnerable to conduction-blocking gas embolisms and cost more for a plant to build, a tension necessarily shaping xylem conduit diameters along plant stems. We build on this expectation to present the Widened Pipe Model (WPM) of plant hydraulic evolution, testing it against a global dataset. The WPM predicts that xylem conduits should be narrowest at the stem tips, widening quickly before plateauing toward the stem base. This universal profile emerges from Pareto modeling of a trade-off between just two competing vectors of natural selection: one favoring rapid widening of conduits tip to base, minimizing hydraulic resistance, and another favoring slow widening of conduits, minimizing carbon cost and embolism risk. Our data spanning terrestrial plant orders, life forms, habitats, and sizes conform closely to WPM predictions. The WPM highlights carbon economy as a powerful vector of natural selection shaping plant function. It further implies that factors that cause resistance in plant conductive systems, such as conduit pit membrane resistance, should scale in exact harmony with tip-to-base conduit widening. Furthermore, the WPM implies that alterations in the environments of individual plants should lead to changes in plant height, for example, shedding terminal branches and resprouting at lower height under drier climates, thus achieving narrower and potentially more embolism-resistant conduits.
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12
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Abstract
Soil-salinization affects, to a different extent, more than one-third of terrestrial river basins (estimate based on the Food and Agriculture Organization Harmonized World Soil Database, 2012). Among these, many are endorheic and ephemeral systems already encompassing different degrees of aridity, land degradation, and vulnerability to climate change. The primary effect of salinization is to limit plant water uptake and evapotranspiration, thereby reducing available soil moisture and impairing soil fertility. In this, salinization resembles aridity and-similarly to aridity-may impose significant controls on hydrological partitioning and the strength of land-vegetation-atmosphere interactions at the catchment scale. However, the long-term impacts of salinization on the terrestrial water balance are still largely unquantified. Here, we introduce a modified Budyko's framework explicitly accounting for catchment-scale salinization and species-specific plant salt tolerance. The proposed framework is used to interpret the water-budget data of 237 Australian catchments-29% of which are already severely salt-affected-from the Australian Water Availability Project (AWAP). Our results provide theoretical and experimental evidence that salinization does influence the hydrological partitioning of salt-affected watersheds, imposing significant constraints on water availability and enhancing aridity. The same approach can be applied to estimate salinization level and vegetation salt tolerance at the basin scale, which would be difficult to assess through classical observational techniques. We also demonstrate that plant salt tolerance has a preeminent role in regulating the feedback of vegetation on the soil water budget of salt-affected basins.
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13
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Qiu R, Katul GG. Maximizing leaf carbon gain in varying saline conditions: An optimization model with dynamic mesophyll conductance. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 101:543-554. [PMID: 31571298 DOI: 10.1111/tpj.14553] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 09/10/2019] [Accepted: 09/20/2019] [Indexed: 06/10/2023]
Abstract
While the adverse effects of elevated salinity levels on leaf gas exchange in many crops are not in dispute, representing such effects on leaf photosynthetic rates (A) continues to draw research attention. Here, an optimization model for stomatal conductance (gc ) that maximizes A while accounting for mesophyll conductance (gm ) was used to interpret new leaf gas exchange measurements collected for five irrigation water salinity levels. A function between chloroplastic CO2 concentration (cc ) and intercellular CO2 concentration (ci ) modified by salinity stress to estimate gm was proposed. Results showed that with increased salinity, the estimated gm and maximum photosynthetic capacity were both reduced, whereas the marginal water use efficiency λ increased linearly. Adjustments of gm , λ and photosynthetic capacity were shown to be consistent with a large corpus of drought-stress experiments. The inferred model parameters were then used to evaluate the combined effects of elevated salinity and atmospheric CO2 concentration (ca ) on leaf gas exchange. For a given salinity level, increasing ca increased A linearly, but these increases were accompanied by mild reductions in gc and transpiration. The ca level needed to ameliorate A reductions due to increased salinity is also discussed using the aforementioned model calculations.
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Affiliation(s)
- Rangjian Qiu
- Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Jiangsu Key Laboratory of Agricultural Meteorology, School of Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing, 210044, China
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
| | - Gabriel G Katul
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
- Department of Civil and Environmental Engineering, Duke University, Durham, NC, 27708, USA
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