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Kotula L, Clode PL, Ranathunge K, Lambers H. Role of roots in adaptation of soil-indifferent Proteaceae to calcareous soils in south-western Australia. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:1490-1505. [PMID: 33170269 DOI: 10.1093/jxb/eraa515] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 11/01/2020] [Indexed: 06/11/2023]
Abstract
Very few of the >650 Proteaceae species in south-western Australia cope with the high calcium (Ca) levels in young, calcareous soils (soil indifferent); most are Ca sensitive and occur on nutrient-impoverished, acidic soils (calcifuge). We assessed possible control points for Ca transport across roots of two soil-indifferent (Hakea prostrata and Banksia prionotes) and two calcifuge (H. incrassata and B. menziesii) Proteaceae. Using quantitative X-ray microanalysis, we investigated cell-specific elemental Ca concentrations at two positions behind the apex in relation to development of apoplastic barriers in roots of plants grown in nutrient solution with low or high Ca supply. In H. prostrata, Ca accumulated in outer cortical cells at 20 mm behind the apex, but [Ca] was low in other cell types. In H. incrassata, [Ca] was low in all cells. Accumulation of Ca in roots of H. prostrata corresponded to development of apoplastic barriers in the endodermis. We found similar [Ca] profiles in roots and similar [Ca] in leaves of two contrasting Banksia species. Soil-indifferent Hakea and Banksia species show different strategies to inhabit calcareous soils: H. prostrata intercepts Ca in roots, reducing transport to shoots, whereas B. prionotes allocates Ca to specific leaf cells.
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Affiliation(s)
- Lukasz Kotula
- UWA School of Agriculture and Environment, The University of Western Australia, Perth, WA, Australia
- UWA School of Biological Sciences, The University of Western Australia, Perth, WA, Australia
| | - Peta L Clode
- UWA School of Biological Sciences, The University of Western Australia, Perth, WA, Australia
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, WA, Australia
| | - Kosala Ranathunge
- UWA School of Biological Sciences, The University of Western Australia, Perth, WA, Australia
| | - Hans Lambers
- UWA School of Biological Sciences, The University of Western Australia, Perth, WA, Australia
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Li Z, Mei X, Li T, Yang S, Qin L, Li B, Zu Y. Effects of calcium application on activities of membrane transporters in Panax notoginseng under cadmium stress. CHEMOSPHERE 2021; 262:127905. [PMID: 33182152 DOI: 10.1016/j.chemosphere.2020.127905] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 07/31/2020] [Accepted: 08/02/2020] [Indexed: 06/11/2023]
Abstract
Pot experiments were conducted to study combined effects of Ca and Cd on contents of Cd and Ca, and membrane transporters activities (CC (calcium channel protein), ATPase and CAXs (cationic/H+ antiporter) of two-year old Panax notoginseng with application of different concentrations of Ca2+ (0, 180 and 360 mgkg-1, prepared by Ca(OH)2 and CaCl2, respectively) under Cd2+ (0, 0.6, 6.0, and 12.0 mgkg-1, prepared by CdCl2•2.5H2O) treatments. The results showed that soil available Cd contents decreased with Ca(OH)2 and CaCl2 application. Soil pH value increased with Ca(OH)2 application. The contents of Cd in all parts of P. notoginseng increased with the increase in Cd treatment concentrations. The Cd content of P. notoginseng decreased with Ca(OH)2 and CaCl2 treatments. The activities of CC and ATPase in the main root of P. notoginseng decreased with the increase in Cd treatment concentrations and application of CaCl2. The activities of CC and ATPase increased with Ca(OH)2application. The activity of CAXs in the main root of P. notoginseng increased with the increase of Cd treatment concentration. The results indicate that Ca and Cd should be both related to membrane transporters activities and activities of CC, ATPase and CAXs are promoted by cooperation of Ca2+and OH+, which suggest the Ca(OH)2 application should be better than application of CaCl2 for Cd detoxification.
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Affiliation(s)
- Zuran Li
- College of Landscape and Horticulture, Yunnan Agricultural University, Kunming, 650201, China
| | - Xinyue Mei
- College of Resources and Environment, Yunnan Agricultural University, Kunming, 650201, China
| | - Tao Li
- College of Resources and Environment, Yunnan Agricultural University, Kunming, 650201, China
| | - Shu Yang
- College of Science, Yunnan Agricultural University, Kunming, 650201, China
| | - Li Qin
- College of Resources and Environment, Yunnan Agricultural University, Kunming, 650201, China
| | - Bo Li
- College of Resources and Environment, Yunnan Agricultural University, Kunming, 650201, China
| | - Yanqun Zu
- College of Resources and Environment, Yunnan Agricultural University, Kunming, 650201, China.
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3
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Tao Q, Jupa R, Liu Y, Luo J, Li J, Kováč J, Li B, Li Q, Wu K, Liang Y, Lux A, Wang C, Li T. Abscisic acid-mediated modifications of radial apoplastic transport pathway play a key role in cadmium uptake in hyperaccumulator Sedum alfredii. PLANT, CELL & ENVIRONMENT 2019; 42:1425-1440. [PMID: 30577078 DOI: 10.1111/pce.13506] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 12/11/2018] [Accepted: 12/14/2018] [Indexed: 05/18/2023]
Abstract
Abscisic acid (ABA) is a key phytohormone underlying plant resistance to toxic metals. However, regulatory effects of ABA on apoplastic transport in roots and consequences for uptake of metal ions are poorly understood. Here, we demonstrate how ABA regulates development of apoplastic barriers in roots of two ecotypes of Sedum alfredii and assess effects on cadmium (Cd) uptake. Under Cd treatment, increased endogenous ABA level was detected in roots of nonhyperaccumulating ecotype (NHE) due to up-regulated expressions of ABA biosynthesis genes (SaABA2, SaNCED), but no change was observed in hyperaccumulating ecotype (HE). Simultaneously, endodermal Casparian strips (CSs) and suberin lamellae (SL) were deposited closer to root tips of NHE compared with HE. Interestingly, the vessel-to-CSs overlap was identified as an ABA-driven anatomical trait. Results of correlation analyses and exogenous applications of ABA/Abamine indicate that ABA regulates development of both types of apoplastic barriers through promoting activities of phenylalanine ammonialyase, peroxidase, and expressions of suberin-related genes (SaCYP86A1, SaGPAT5, and SaKCS20). Using scanning ion-selected electrode technique and PTS tracer confirmed that ABA-promoted deposition of CSs and SL significantly reduced Cd entrance into root stele. Therefore, maintenance of low ABA levels in HE minimized deposition of apoplastic barriers and allowed maximization of Cd uptake via apoplastic pathway.
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Affiliation(s)
- Qi Tao
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China
| | - Radek Jupa
- Department of Experimental Biology, Faculty of Science, Masaryk University, 611 37, Brno, Czech Republic
| | - Yuankun Liu
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Jipeng Luo
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Jinxing Li
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Ján Kováč
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15, Bratislava, Slovakia
| | - Bing Li
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China
| | - Qiquan Li
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China
| | - Keren Wu
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Yongchao Liang
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Alexander Lux
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15, Bratislava, Slovakia
| | - Changquan Wang
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China
| | - Tingqiang Li
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
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Wang H, Wang Z, Dong X. Anatomical structures of fine roots of 91 vascular plant species from four groups in a temperate forest in Northeast China. PLoS One 2019; 14:e0215126. [PMID: 31042717 PMCID: PMC6494041 DOI: 10.1371/journal.pone.0215126] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2017] [Accepted: 03/28/2019] [Indexed: 11/19/2022] Open
Abstract
Fine roots of plants play an important role in terrestrial ecosystems. There is a close association between the anatomical characteristics and physiological and ecological functions of plants, but we still have a very limited knowledge of anatomical traits. For example, (1) we do not know if herbs and grasses have anatomical patterns similar to those of woody plants, and (2) the variation among different woody plants in the same ecosystem is unclear. In the present study, we analysed the anatomical structures of the fine root systems of various groups of vascular plants (ferns, eudicot herbs, monocots and woody plants) from the same ecosystem (a natural secondary forest on Mao'er Mountain, Heilongjiang, China) to answer the following questions: (1) How does the anatomy of the fine roots change with root order in various plant groups in the same ecosystem? (2) What is the pattern of variation within group? The results show that anatomical traits can be divided into 3 categories: traits that indicate the root capacity to transport resource along the root (stele diameter, xylem cell diameter and xylem cell area); traits that indicate absorptive capacity cortical thickness, (the number of cortical cell layers and the diameter of cortical cells); and traits that are integrated indicators (diameter and the stele to root diameter ratio). The traits indicate the root capacity to transport resource along the root order is generally similar among groups, but absorptive capacity is very different. The shift in function is the main factor influencing the fine root anatomy. Some traits show large variation within groups, but the variations in other traits are small. The traits indicate that the lower-order roots (absorbing roots) in distinct groups are of the first one or two root order in ferns, the first two or three orders in eudicot herbs, the first (only two root orders) or first two orders (more than three root orders) in monocots and the first four or five root orders in woody plants and the other roots are higher-order roots (transport roots). The result will helpful to understand the similarities and differences among groups and the physiological and ecological functions of plant roots.
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Affiliation(s)
- Hongfeng Wang
- School of Forestry, Northeast Forestry University, Harbin, China
| | - Zhengquan Wang
- School of Forestry, Northeast Forestry University, Harbin, China
| | - Xueyun Dong
- School of Science, Harbin University, Harbin, China
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Kim YX, Ranathunge K, Lee S, Lee Y, Lee D, Sung J. Composite Transport Model and Water and Solute Transport across Plant Roots: An Update. FRONTIERS IN PLANT SCIENCE 2018; 9:193. [PMID: 29503659 PMCID: PMC5820301 DOI: 10.3389/fpls.2018.00193] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 02/01/2018] [Indexed: 05/19/2023]
Abstract
The present review examines recent experimental findings in root transport phenomena in terms of the composite transport model (CTM). It has been a well-accepted conceptual model to explain the complex water and solute flows across the root that has been related to the composite anatomical structure. There are three parallel pathways involved in the transport of water and solutes in roots - apoplast, symplast, and transcellular paths. The role of aquaporins (AQPs), which facilitate water flows through the transcellular path, and root apoplast is examined in terms of the CTM. The contribution of the plasma membrane bound AQPs for the overall water transport in the whole plant level was varying depending on the plant species, age of roots with varying developmental stages of apoplastic barriers, and driving forces (hydrostatic vs. osmotic). Many studies have demonstrated that the apoplastic barriers, such as Casparian bands in the primary anticlinal walls and suberin lamellae in the secondary cell walls, in the endo- and exodermis are not perfect barriers and unable to completely block the transport of water and some solute transport into the stele. Recent research on water and solute transport of roots with and without exodermis triggered the importance of the extension of conventional CTM adding resistances that arrange in series (epidermis, exodermis, mid-cortex, endodermis, and pericycle). The extension of the model may answer current questions about the applicability of CTM for composite water and solute transport of roots that contain complex anatomical structures with heterogeneous cell layers.
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Affiliation(s)
- Yangmin X. Kim
- Division of Soil and Fertilizer, National Institute of Agricultural Sciences, Rural Development Administration, Wanju, South Korea
| | - Kosala Ranathunge
- School of Biological Sciences, The University of Western Australia, Perth, WA, Australia
| | - Seulbi Lee
- Division of Soil and Fertilizer, National Institute of Agricultural Sciences, Rural Development Administration, Wanju, South Korea
| | - Yejin Lee
- Division of Soil and Fertilizer, National Institute of Agricultural Sciences, Rural Development Administration, Wanju, South Korea
| | - Deogbae Lee
- Division of Soil and Fertilizer, National Institute of Agricultural Sciences, Rural Development Administration, Wanju, South Korea
| | - Jwakyung Sung
- Division of Soil and Fertilizer, National Institute of Agricultural Sciences, Rural Development Administration, Wanju, South Korea
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Song WP, Chen W, Yi JW, Wang HC, Huang XM. Ca Distribution Pattern in Litchi Fruit and Pedicel and Impact of Ca Channel Inhibitor, La 3. FRONTIERS IN PLANT SCIENCE 2017; 8:2228. [PMID: 29375603 PMCID: PMC5767242 DOI: 10.3389/fpls.2017.02228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 12/19/2017] [Indexed: 05/02/2023]
Abstract
Calcium (Ca) deficiency in fruit causes various physiological disorders leading to quality loss. However, disorders related to Ca deficiency are not simply caused by a shortage of calcium supply. Ca distribution is also an important relation. This study examined Ca distribution pattern in fruit and pedicel in litchi (Litchi chinensis Sonn.) and the influence of Ca channel inhibitor La3+ on fruit Ca uptake and distribution. In situ distribution of Ca in the phloem and xylem tissues of the pedicel was visualized by Ca mapping with X-ray microanalyzer. Ca2+ analogy Sr2+ was used to trace Ca2+ transport pathway to fruit as well as distribution pattern. The results showed Ca was more distributed in the pericarp, especially the distal part. Ca level in the bark/phloem was always significantly higher than in the xylem and increased with stem age, suggesting constant influx of Ca into the phloem from the xylem. La3+ increased the ratio of Ca in the xylem to that in the bark in the pedicel and significantly reduced Ca accumulation by 55.6% in fruit, suggesting influx of Ca into the symplast was involved in fruit Ca uptake. Sr2+ introduced from fruit stalk was found to be transported to fruit through the phloem as Sr was largely distributed in the phloem, and fruit stalk girdling significantly reduced Sr accumulation in the pericarp. Ca mapping across the pedicel revealed Ca-rich sites in the parenchyma cells in the phloem and along the cambium, where abundant Ca oxalate crystals were found. The results suggested extensive influx of Ca from xylem/apoplast pathway into the phloem/symplast pathway in the pedicel, which enables phloem/symplast pathway to contribute a considerable part to Ca uptake in litchi fruit.
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Affiliation(s)
| | | | - Jun-Wen Yi
- *Correspondence: Xu-Ming Huang, Jun-Wen Yi,
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Hocking B, Tyerman SD, Burton RA, Gilliham M. Fruit Calcium: Transport and Physiology. FRONTIERS IN PLANT SCIENCE 2016; 7:569. [PMID: 27200042 PMCID: PMC4850500 DOI: 10.3389/fpls.2016.00569] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Accepted: 04/13/2016] [Indexed: 05/18/2023]
Abstract
Calcium has well-documented roles in plant signaling, water relations and cell wall interactions. Significant research into how calcium impacts these individual processes in various tissues has been carried out; however, the influence of calcium on fruit ripening has not been thoroughly explored. Here, we review the current state of knowledge on how calcium may impact the development, physical traits and disease susceptibility of fruit through facilitating developmental and stress response signaling, stabilizing membranes, influencing water relations and modifying cell wall properties through cross-linking of de-esterified pectins. We explore the involvement of calcium in hormone signaling integral to the physiological mechanisms behind common disorders that have been associated with fruit calcium deficiency (e.g., blossom end rot in tomatoes or bitter pit in apples). This review works toward an improved understanding of how the many roles of calcium interact to influence fruit ripening, and proposes future research directions to fill knowledge gaps. Specifically, we focus mostly on grapes and present a model that integrates existing knowledge around these various functions of calcium in fruit, which provides a basis for understanding the physiological impacts of sub-optimal calcium nutrition in grapes. Calcium accumulation and distribution in fruit is shown to be highly dependent on water delivery and cell wall interactions in the apoplasm. Localized calcium deficiencies observed in particular species or varieties can result from differences in xylem morphology, fruit water relations and pectin composition, and can cause leaky membranes, irregular cell wall softening, impaired hormonal signaling and aberrant fruit development. We propose that the role of apoplasmic calcium-pectin crosslinking, particularly in the xylem, is an understudied area that may have a key influence on fruit water relations. Furthermore, we believe that improved knowledge of the calcium-regulated signaling pathways that control ripening would assist in addressing calcium deficiency disorders and improving fruit pathogen resistance.
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Affiliation(s)
- Bradleigh Hocking
- Plant Transport and Signaling Laboratory, ARC Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen OsmondSA, Australia
- ARC Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen OsmondSA, Australia
| | - Stephen D. Tyerman
- Plant Transport and Signaling Laboratory, ARC Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen OsmondSA, Australia
| | - Rachel A. Burton
- ARC Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen OsmondSA, Australia
| | - Matthew Gilliham
- Plant Transport and Signaling Laboratory, ARC Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen OsmondSA, Australia
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Ronchini M, Cherchi L, Cantamessa S, Lanfranchi M, Vianelli A, Gerola P, Berta G, Fumagalli A. Palladium uptake by Pisum sativum: partitioning and effects on growth and reproduction. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:7600-11. [PMID: 25639246 DOI: 10.1007/s11356-015-4132-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 01/15/2015] [Indexed: 06/04/2023]
Abstract
Environmental palladium levels are increasing because of anthropogenic activities. The considerable mobility of the metal, due to solubilisation phenomena, and its known bioavailability may indicate interactions with higher organisms. The aim of the study was to determine the Pd uptake and distribution in the various organs of the higher plant Pisum sativum and the metal-induced effects on its growth and reproduction. P. sativum was grown in vermiculite with a modified Hoagland's solution of nutrients in the presence of Pd at concentrations ranging 0.10-25 mg/L. After 8-10 weeks in a controlled environment room, plants were harvested and dissected to isolate the roots, stems, leaves, pods and peas. The samples were analysed for Pd content using AAS and SEM-EDX. P. sativum absorbed Pd, supplied as K₂PdCl₄, beginning at seed germination and continuing throughout its life. Minimal doses (0.10-1.0 mg Pd/L) severely inhibited pea reproductive processes while showing a peculiar hormetic effect on root development. Pd concentrations ≥1 mg/L induced developmental delay, with late growth resumption, increased leaf biomass (up to 25%) and a 15-20% reduction of root mass. Unsuccessful repeated blossoming efforts led to misshapen pods and no seed production. Photosynthesis was also disrupted. The absorbed Pd (ca. 0.5 % of the supplied metal) was primarily fixed in the root, specifically in the cortex, reaching concentrations up to 200 μg/g. The metal moved through the stem (up to 1 μg/g) to the leaves (2 μg/g) and pods (0.3 μg/g). The presence of Pd in the pea fruits, together with established evidence of environmental Pd accumulation and bioavailability, suggests possible contamination of food plants and propagation in the food chain and must be the cause for concern.
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Affiliation(s)
- Matteo Ronchini
- Dipartimento di Scienze Teoriche e Applicate, Università degli Studi dell'Insubria, via J. H. Dunant 3, 21100, Varese, Italy
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Transcriptome-wide identification of the genes responding to replanting disease in Rehmannia glutinosa L. roots. Mol Biol Rep 2014; 42:881-92. [DOI: 10.1007/s11033-014-3825-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 11/10/2014] [Indexed: 01/22/2023]
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Hu B, Henry A, Brown KM, Lynch JP. Root cortical aerenchyma inhibits radial nutrient transport in maize (Zea mays). ANNALS OF BOTANY 2014; 113:181-9. [PMID: 24249807 PMCID: PMC3864730 DOI: 10.1093/aob/mct259] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Accepted: 09/11/2013] [Indexed: 05/17/2023]
Abstract
BACKGROUND AND AIMS Formation of root cortical aerenchyma (RCA) can be induced by nutrient deficiency. In species adapted to aerobic soil conditions, this response is adaptive by reducing root maintenance requirements, thereby permitting greater soil exploration. One trade-off of RCA formation may be reduced radial transport of nutrients due to reduction in living cortical tissue. To test this hypothesis, radial nutrient transport in intact roots of maize (Zea mays) was investigated in two radiolabelling experiments employing genotypes with contrasting RCA. METHODS In the first experiment, time-course dynamics of phosphate loading into the xylem were measured from excised nodal roots that varied in RCA formation. In the second experiment, uptake of phosphate, calcium and sulphate was measured in seminal roots of intact young plants in which variation in RCA was induced by treatments altering ethylene action or genetic differences. KEY RESULTS In each of three paired genotype comparisons, the rate of phosphate exudation of high-RCA genotypes was significantly less than that of low-RCA genotypes. In the second experiment, radial nutrient transport of phosphate and calcium was negatively correlated with the extent of RCA for some genotypes. CONCLUSIONS The results support the hypothesis that RCA can reduce radial transport of some nutrients in some genotypes, which could be an important trade-off of this trait.
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Affiliation(s)
- Bo Hu
- Department of Plant Science, The Pennsylvania State University, University Park, PA 16802, USA
- Agriculture Department, Inner Mongolia Agriculture University, Hohhot, P. R. China
| | - Amelia Henry
- Intercollege Program in Plant Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Kathleen M. Brown
- Department of Plant Science, The Pennsylvania State University, University Park, PA 16802, USA
- Intercollege Program in Plant Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Jonathan P. Lynch
- Department of Plant Science, The Pennsylvania State University, University Park, PA 16802, USA
- Intercollege Program in Plant Biology, The Pennsylvania State University, University Park, PA 16802, USA
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Abstract
A Casparian strip-bearing endodermis is a feature that has been invariably present in the roots of ferns and angiosperms for approximately 400 million years. As the innermost cortical layer that surrounds the central vasculature of roots, the endodermis acts as a barrier to the free diffusion of solutes from the soil into the stele. Based on an enormous body of anatomical and physiological work, the protective endodermal diffusion barrier is thought to be of major importance for many aspects of root biology, reaching from efficient water and nutrient transport to defense against soil-borne pathogens. Until recently, however, we were ignorant about the genes and mechanisms that drive the differentiation of this intricately structured barrier. Recent work in Arabidopsis has now identified the first major players in Casparian strip formation. A mechanistic understanding of endodermal differentiation will finally allow us to specifically interfere with endodermal barrier function and study the effects on plant growth and survival under various stress conditions. Here, I critically review the major findings and models related to endodermal structure and function from other plant species and assess them in light of recent molecular data from Arabidopsis, pointing out where the older, descriptive work can provide a framework and inspiration for further molecular dissection.
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Affiliation(s)
- Niko Geldner
- Department of Plant Molecular Biology, University of Lausanne, 1015 Lausanne, Switzerland.
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12
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Song WY, Choi KS, Alexis DA, Martinoia E, Lee Y. Brassica juncea plant cadmium resistance 1 protein (BjPCR1) facilitates the radial transport of calcium in the root. Proc Natl Acad Sci U S A 2011; 108:19808-13. [PMID: 22089235 PMCID: PMC3241789 DOI: 10.1073/pnas.1104905108] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Calcium (Ca) is an important structural component of plant cell walls and an intracellular messenger in plants and animals. Therefore, plants tightly control the balance of Ca by regulating Ca uptake and its transfer from cell to cell and organ to organ. Here, we propose that Brassica juncea PCR1 (PCR1), a member of the plant cadmium resistance (PCR) protein family in Indian mustard, is a Ca(2+) efflux transporter that is required for the efficient radial transfer of Ca(2+) in the root and is implicated in the translocation of Ca to the shoot. Knock-down lines of BjPCR1 were greatly stunted and translocated less Ca to the shoot than did the corresponding WT. The localization of BjPCR1 to the plasma membrane and the preferential expression of BjPCR1 in the root epidermal cells of WT plants suggest that BjPCR1 antisense plants could not efficiently transfer Ca(2+) from the root epidermis to the cells located inside the root. Protoplasts isolated from BjPCR1 antisense lines had lower Ca(2+) efflux activity than did those of the WT, and membrane vesicles isolated from BjPCR1-expressing yeast exhibited increased Ca(2+) transport activity. Inhibitor studies, together with theoretical considerations, indicate that BjPCR1 exports one Ca(2+) in exchange for three protons. Root hair-specific expression of BjPCR1 in Arabidopsis results in plants that exhibit increased Ca(2+) resistance and translocation. In conclusion, our data support the hypothesis that BjPCR1 is an exporter required for the translocation of Ca(2+) from the root epidermis to the inner cells, and ultimately to the shoot.
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Affiliation(s)
- Won-Yong Song
- Institute of Plant Biology, University of Zurich, CH-8008 Zurich, Switzerland
- Pohang University of Science and Technology-University of Zurich Cooperative Laboratory, Department of Integrative Bioscience and Biotechnology, World Class University Program, Pohang University of Science and Technology, Pohang 790-784, Korea; and
- Division of Applied Biology, College of Agriculture and Life Sciences, Chungnam National University, Daejeon 305-764, Korea
| | - Kwan-Sam Choi
- Division of Applied Biology, College of Agriculture and Life Sciences, Chungnam National University, Daejeon 305-764, Korea
| | - De Angeli Alexis
- Institute of Plant Biology, University of Zurich, CH-8008 Zurich, Switzerland
| | - Enrico Martinoia
- Institute of Plant Biology, University of Zurich, CH-8008 Zurich, Switzerland
- Pohang University of Science and Technology-University of Zurich Cooperative Laboratory, Department of Integrative Bioscience and Biotechnology, World Class University Program, Pohang University of Science and Technology, Pohang 790-784, Korea; and
| | - Youngsook Lee
- Pohang University of Science and Technology-University of Zurich Cooperative Laboratory, Department of Integrative Bioscience and Biotechnology, World Class University Program, Pohang University of Science and Technology, Pohang 790-784, Korea; and
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Wu H, Jaeger M, Wang M, Li B, Zhang BG. Three-dimensional distribution of vessels, passage cells and lateral roots along the root axis of winter wheat (Triticum aestivum). ANNALS OF BOTANY 2011; 107:843-53. [PMID: 21289027 PMCID: PMC3077985 DOI: 10.1093/aob/mcr005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 10/21/2010] [Accepted: 11/23/2010] [Indexed: 05/18/2023]
Abstract
BACKGROUND AND AIMS The capacity of a plant to absorb and transport water and nutrients depends on anatomical structures within the roots and their co-ordination. However, most descriptions of root anatomical structure are limited to 2-D cross-sections, providing little information on 3-D spatial relationships and hardly anything on their temporal evolution. Three-dimensional reconstruction and visualization of root anatomical structures can illustrate spatial co-ordination among cells and tissues and provide new insights and understanding of the interrelation between structure and function. METHODS Classical paraffin serial-section methods, image processing, computer-aided 3-D reconstruction and 3-D visualization techniques were combined to analyse spatial relationships among metaxylem vessels, passage cells and lateral roots in nodal roots of winter wheat (Triticum aestivum). KEY RESULTS 3-D reconstruction demonstrated that metaxylem vessels were neither parallel, nor did they run directly along the root axis from the root base to the root tip; rather they underwent substitution and transition. Most vessels were connected to pre-existent or newly formed vessels by pits on their lateral walls. The spatial distributions of both passage cells and lateral roots exhibited similar position-dependent patterns. In the transverse plane, the passage cells occurred opposite the poles of the protoxylem and the lateral roots opposite those of the protophloem. Along the axis of a young root segment, the passage cells were arranged in short and discontinuous longitudinal files, thus as the tissues mature, the sequence in which the passage cells lose their transport function is not basipetal. In older segments, passage cells decreased drastically in number and coexisted with lateral roots. The spatial distribution of lateral roots was similar to that of the passage cells, mirroring their similar functions as lateral pathways for water and nutrient transport to the stele. CONCLUSIONS With the 3-D reconstruction and visualization techniques developed here, the spatial relationships between vessels, passage cells and lateral roots and the temporal evolution of these relationships can be described. The technique helps to illustrate synchronization and spatial co-ordination among the root's radial and axial pathways for water and nutrient transport and the interdependence of structure and function in the root.
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Affiliation(s)
- Haiwen Wu
- Key Laboratory of Plant–Soil Interactions, College of Resources and Environmental Sciences, China Agricultural University, 100193 Beijing, China
| | - Marc Jaeger
- CIRAD-AMAP, EPI Digiplante, Bd de la Lironde 34398, Montpellier cedex 5, France
| | - Mao Wang
- College of Biological Sciences, China Agricultural University, 100193 Beijing, China
| | - Baoguo Li
- Key Laboratory of Plant–Soil Interactions, College of Resources and Environmental Sciences, China Agricultural University, 100193 Beijing, China
| | - Bao Gui Zhang
- Key Laboratory of Plant–Soil Interactions, College of Resources and Environmental Sciences, China Agricultural University, 100193 Beijing, China
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Gilliham M, Dayod M, Hocking BJ, Xu B, Conn SJ, Kaiser BN, Leigh RA, Tyerman SD. Calcium delivery and storage in plant leaves: exploring the link with water flow. JOURNAL OF EXPERIMENTAL BOTANY 2011; 62:2233-50. [PMID: 21511913 DOI: 10.1093/jxb/err111] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Calcium (Ca) is a unique macronutrient with diverse but fundamental physiological roles in plant structure and signalling. In the majority of crops the largest proportion of long-distance calcium ion (Ca(2+)) transport through plant tissues has been demonstrated to follow apoplastic pathways, although this paradigm is being increasingly challenged. Similarly, under certain conditions, apoplastic pathways can dominate the proportion of water flow through plants. Therefore, tissue Ca supply is often found to be tightly linked to transpiration. Once Ca is deposited in vacuoles it is rarely redistributed, which results in highly transpiring organs amassing large concentrations of Ca ([Ca]). Meanwhile, the nutritional flow of Ca(2+) must be regulated so it does not interfere with signalling events. However, water flow through plants is itself regulated by Ca(2+), both in the apoplast via effects on cell wall structure and stomatal aperture, and within the symplast via Ca(2+)-mediated gating of aquaporins which regulates flow across membranes. In this review, an integrated model of water and Ca(2+) movement through plants is developed and how this affects [Ca] distribution and water flow within tissues is discussed, with particular emphasis on the role of aquaporins.
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Affiliation(s)
- Matthew Gilliham
- Waite Research Institute, School of Agriculture, Food and Wine, University of Adelaide, PMB1, Glen Osmond, SA, 5064, Australia
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Ranathunge K, Schreiber L, Franke R. Suberin research in the genomics era--new interest for an old polymer. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2011; 180:399-413. [PMID: 21421386 DOI: 10.1016/j.plantsci.2010.11.003] [Citation(s) in RCA: 137] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Revised: 11/08/2010] [Accepted: 11/09/2010] [Indexed: 05/22/2023]
Abstract
Suberin is an apoplastic biopolymer with tissue-specific deposition in the cell walls of the endo- and exodermis of roots, of periderms including wound periderm and other border tissues. Suberised cell walls contain both polyaliphatic and polyaromatic domains which are supposedly cross-linked. The predominant aliphatic components are ω-hydroxyacids, α,ω-diacids, fatty acids and primary alcohols, whereas hydroxycinnamic acids, especially ferulic acid, are the main components of the polyaromatic domain. Although the monomeric composition of suberin has been known for decades, its biosynthesis and deposition has mainly been a subject of speculation. Only recently, significant progress elucidating suberin biosynthesis has been achieved using molecular genetic approaches, especially in the model species Arabidopsis. In parallel, the long-standing hypothesis that suberin functions as an apoplastic barrier has been corroborated by sophisticated, quantitative physiological studies in the past decade. These studies demonstrated that suberised cell walls could act as barriers, minimising the movement of water and nutrients, restricting pathogen invasion and impeding toxic gas diffusion. In addition, suberised cell walls provide a barrier to radial oxygen loss from roots to the anaerobic root substrate in wetland plants. The recent onset of multidisciplinary approaches combining genetic, analytical and physiological studies has begun to deliver further insights into the physiological importance of suberin depositions in plants.
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Affiliation(s)
- Kosala Ranathunge
- Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee 1, D-53115 Bonn, Germany
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Dayod M, Tyerman SD, Leigh RA, Gilliham M. Calcium storage in plants and the implications for calcium biofortification. PROTOPLASMA 2010; 247:215-31. [PMID: 20658253 DOI: 10.1007/s00709-010-0182-0] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Accepted: 07/06/2010] [Indexed: 05/20/2023]
Abstract
Calcium (Ca) is an essential nutrient for plants and animals, with key structural and signalling roles, and its deficiency in plants can result in poor biotic and abiotic stress tolerance, reduced crop quality and yield. Likewise, low Ca intake in humans has been linked to various diseases (e.g. rickets, osteoporosis, hypertension and colorectal cancer) which can threaten quality of life and have major economic costs. Biofortification of various food crops with Ca has been suggested as a good method to enhance human intake of Ca and is advocated as an economically and environmentally advantageous strategy. Efforts to enhance Ca content of crops via transgenic means have had promising results. Overall Ca content of transgenic plants has been increased but in some cases adverse affects on plant function have been observed. This suggests that a better understanding of how Ca ions (Ca(2+)) are stored and transported through plants is required to maximise the effectiveness of future approaches.
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Affiliation(s)
- Maclin Dayod
- Waite Research Institute, School of Agriculture, Food and Wine, University of Adelaide, PMB1, Glen Osmond, SA 5064, Australia
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17
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Dayod M, Tyerman SD, Leigh RA, Gilliham M. Calcium storage in plants and the implications for calcium biofortification. PROTOPLASMA 2010. [PMID: 20658253 DOI: 10.1007/s00709-010-0182-180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Calcium (Ca) is an essential nutrient for plants and animals, with key structural and signalling roles, and its deficiency in plants can result in poor biotic and abiotic stress tolerance, reduced crop quality and yield. Likewise, low Ca intake in humans has been linked to various diseases (e.g. rickets, osteoporosis, hypertension and colorectal cancer) which can threaten quality of life and have major economic costs. Biofortification of various food crops with Ca has been suggested as a good method to enhance human intake of Ca and is advocated as an economically and environmentally advantageous strategy. Efforts to enhance Ca content of crops via transgenic means have had promising results. Overall Ca content of transgenic plants has been increased but in some cases adverse affects on plant function have been observed. This suggests that a better understanding of how Ca ions (Ca(2+)) are stored and transported through plants is required to maximise the effectiveness of future approaches.
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Affiliation(s)
- Maclin Dayod
- Waite Research Institute, School of Agriculture, Food and Wine, University of Adelaide, PMB1, Glen Osmond, SA 5064, Australia
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18
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Conn S, Gilliham M. Comparative physiology of elemental distributions in plants. ANNALS OF BOTANY 2010; 105:1081-102. [PMID: 20410048 PMCID: PMC2887064 DOI: 10.1093/aob/mcq027] [Citation(s) in RCA: 184] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Revised: 11/16/2009] [Accepted: 12/16/2009] [Indexed: 05/18/2023]
Abstract
BACKGROUND Plants contain relatively few cell types, each contributing a specialized role in shaping plant function. With respect to plant nutrition, different cell types accumulate certain elements in varying amounts within their storage vacuole. The role and mechanisms underlying cell-specific distribution of elements in plants is poorly understood. SCOPE The phenomenon of cell-specific elemental accumulation has been briefly reviewed previously, but recent technological advances with the potential to probe mechanisms underlying elemental compartmentation have warranted an updated evaluation. We have taken this opportunity to catalogue many of the studies, and techniques used for, recording cell-specific compartmentation of particular elements. More importantly, we use three case-study elements (Ca, Cd and Na) to highlight the basis of such phenomena in terms of their physiological implications and underpinning mechanisms; we also link such distributions to the expression of known ion or solute transporters. CONCLUSIONS Element accumulation patterns are clearly defined by expression of key ion or solute transporters. Although the location of element accumulation is fairly robust, alterations in expression of certain solute transporters, through genetic modifications or by growth under stress, result in perturbations to these patterns. However, redundancy or induced pleiotropic expression effects may complicate attempts to characterize the pathways that lead to cell-specific elemental distribution. Accumulation of one element often has consequences on the accumulation of others, which seems to be driven largely to maintain vacuolar and cytoplasmic osmolarity and charge balance, and also serves as a detoxification mechanism. Altered cell-specific transcriptomics can be shown, in part, to explain some of this compensation.
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Affiliation(s)
- Simon Conn
- School of Agriculture, Food, and Wine, University of Adelaide, Waite Campus, Glen Osmond, South Australia 5064, Australia
| | - Matthew Gilliham
- School of Agriculture, Food, and Wine, University of Adelaide, Waite Campus, Glen Osmond, South Australia 5064, Australia
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Yamanaka T, Nakagawa Y, Mori K, Nakano M, Imamura T, Kataoka H, Terashima A, Iida K, Kojima I, Katagiri T, Shinozaki K, Iida H. MCA1 and MCA2 that mediate Ca2+ uptake have distinct and overlapping roles in Arabidopsis. PLANT PHYSIOLOGY 2010; 152:1284-96. [PMID: 20097794 PMCID: PMC2832256 DOI: 10.1104/pp.109.147371] [Citation(s) in RCA: 133] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2009] [Accepted: 01/19/2010] [Indexed: 05/18/2023]
Abstract
Ca(2+) is important for plant growth and development as a nutrient and a second messenger. However, the molecular nature and roles of Ca(2+)-permeable channels or transporters involved in Ca(2+) uptake in roots are largely unknown. We recently identified a candidate for the Ca(2+)-permeable mechanosensitive channel in Arabidopsis (Arabidopsis thaliana), named MCA1. Here, we investigated the only paralog of MCA1 in Arabidopsis, MCA2. cDNA of MCA2 complemented a Ca(2+) uptake deficiency in yeast cells lacking a Ca(2+) channel composed of Mid1 and Cch1. Reverse transcription polymerase chain reaction analysis indicated that MCA2 was expressed in leaves, flowers, roots, siliques, and stems, and histochemical observation showed that an MCA2 promoter::GUS fusion reporter gene was universally expressed in 10-d-old seedlings with some exceptions: it was relatively highly expressed in vascular tissues and undetectable in the cap and the elongation zone of the primary root. mca2-null plants were normal in growth and morphology. In addition, the primary root of mca2-null seedlings was able to normally sense the hardness of agar medium, unlike that of mca1-null or mca1-null mca2-null seedlings, as revealed by the two-phase agar method. Ca(2+) uptake activity was lower in the roots of mca2-null plants than those of wild-type plants. Finally, growth of mca1-null mca2-null plants was more retarded at a high concentration of Mg(2+) added to medium compared with that of mca1-null and mca2-null single mutants and wild-type plants. These results suggest that the MCA2 protein has a distinct role in Ca(2+) uptake in roots and an overlapping role with MCA1 in plant growth.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | - Hidetoshi Iida
- Department of Biology, Tokyo Gakugei University, Koganei, Tokyo 184–8501, Japan (T.Y., Y.N., K.M., M.N., T.I., H.K., A.T., H.I.); Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Kawaguchi, Saitama 332–0012, Japan (T.Y., Y.N., K.S., H.I.); Laboratory of Cell Biology, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma 371–8510, Japan (Y.N., I.K.); Gene Research Center, Tokyo University of Agriculture and Technology, Tokyo 183–8509, Japan (M.N.); Biomembrane Signaling Project 2, Tokyo Metropolitan Institute of Medical Science, Bunkyo-ku, Tokyo 113–8613, Japan (K.I.); Laboratory of Plant Molecular Biology, RIKEN Tsukuba Institute, Tsukuba, Ibaraki 305–0074, Japan (Y.N., T.K., K.S.); and Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki 444–8787, Japan (H.I.)
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New insights into {gamma}-aminobutyric acid catabolism: Evidence for {gamma}-hydroxybutyric acid and polyhydroxybutyrate synthesis in Saccharomyces cerevisiae. Appl Environ Microbiol 2009; 75:4231-9. [PMID: 19411412 DOI: 10.1128/aem.00051-09] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The gamma-aminobutyrate (GABA) shunt, an alternative route for the conversion of alpha-ketoglutarate to succinate, involves the glutamate decarboxylase Gad1p, the GABA transaminase Uga1p and the succinate semialdehyde dehydrogenase Uga2p. This pathway has been extensively described in plants and animals, but its function in yeast remains unclear. We show that the flux through Gad1p is insignificant during fermentation in rich sugar-containing medium, excluding a role for this pathway in redox homeostasis under anaerobic conditions or sugar stress. However, we found that up to 4 g of exogenous GABA/liter was efficiently consumed by yeast. We studied the fate of this consumed GABA. Most was converted into succinate, with a reaction yield of 0.7 mol/mol. We also showed that a large proportion of GABA was stored within cells, indicating a possible role for this molecule in stress tolerance mechanisms or nitrogen storage. Furthermore, based on enzymatic and metabolic evidence, we identified an alternative route for GABA catabolism, involving the reduction of succinate-semialdehyde into gamma-hydroxybutyric acid and the polymerization of gamma-hydroxybutyric acid to form poly-(3-hydroxybutyric acid-co-4-hydroxybutyric acid). This study provides the first demonstration of a native route for the formation of this polymer in yeast. Our findings shed new light on the GABA pathway and open up new opportunities for industrial applications.
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Yamaji N, Ma JF. Spatial distribution and temporal variation of the rice silicon transporter Lsi1. PLANT PHYSIOLOGY 2007; 143:1306-13. [PMID: 17259286 PMCID: PMC1820904 DOI: 10.1104/pp.106.093005] [Citation(s) in RCA: 178] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2006] [Accepted: 01/08/2007] [Indexed: 05/13/2023]
Abstract
Rice (Oryza sativa) is a typical silicon (Si) accumulator and requires a large amount of Si for high-yield production. Recently, a gene (Low silicon rice1 [Lsi1]) encoding a Si transporter was identified in rice roots. Here, we characterized Lsi1 in terms of spatial distribution and temporal variation using both physiological and molecular approaches. Results from a multicompartment transport box experiment showed that the major site for Si uptake was located at the basal zone (>10 mm from the root tip) of the roots rather than at the root tips (<10 mm from the root tip). Consistent with the Si uptake pattern, Lsi1 expression and distribution of the Lsi1 protein were found only in the basal zone of roots. In the basal zones of the seminal, crown, and lateral roots, the Lsi1 protein showed a polar localization at the distal side of both the exodermis and endodermis, where the Casparian bands are formed. This indicates that Lsi1 is required for the transport of Si through the cells of the exodermis and endodermis. Expression of Lsi1 displayed a distinct diurnal pattern. Furthermore, expression was transiently enhanced around the heading stage, which coincides with a high Si requirement during this growth stage. Expression was down-regulated by dehydration stress and abscisic acid, suggesting that expression of Lsi1 may be regulated by abscisic acid.
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Affiliation(s)
- Naoki Yamaji
- Research Institute for Bioresources, Okayama University, Kurashiki 710-0046, Japan
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Van Belleghem F, Cuypers A, Semane B, Smeets K, Vangronsveld J, d'Haen J, Valcke R. Subcellular localization of cadmium in roots and leaves of Arabidopsis thaliana. THE NEW PHYTOLOGIST 2007; 173:495-508. [PMID: 17244044 DOI: 10.1111/j.1469-8137.2006.01940.x] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
We examined the subcellular cadmium (Cd) localization in roots and leaves of wild-type Arabidopsis thaliana (ecotype Columbia) exposed to environmentally relevant Cd concentrations. Energy-dispersive X-ray microanalysis (EDXMA) was performed on high-pressure frozen and freeze-substituted tissues. In the root cortex, Cd was associated with phosphorus (Cd/P) in the apoplast and sulfur (Cd/S) in the symplast, suggesting phosphate and phytochelatin sequestration, respectively. In the endodermis, sequestration of Cd/S was present as fine granular deposits in the vacuole and as large granular deposits in the cytoplasm. In the central cylinder, symplastic accumulation followed a distinct pattern illustrating the importance of passage cells for the uptake of Cd. In the apoplast, a shift of Cd/S granular deposits from the middle lamella towards the plasmalemma was observed. Large amounts of precipitated Cd in the phloem suggest retranslocation from the shoot. In leaves, Cd was detected in tracheids but not in the mesophyll tissue. Extensive symplastic and apoplastic sequestration in the root parenchyma combined with retranslocation via the phloem confirms the excluder strategy of Arabidopsis thaliana.
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Affiliation(s)
| | - Ann Cuypers
- Environmental Biology, Hasselt University - Campus Diepenbeek, Agoralaan Building D, 3590 Diepenbeek Belgium
| | - Brahim Semane
- Environmental Biology, Hasselt University - Campus Diepenbeek, Agoralaan Building D, 3590 Diepenbeek Belgium
| | - Karen Smeets
- Environmental Biology, Hasselt University - Campus Diepenbeek, Agoralaan Building D, 3590 Diepenbeek Belgium
| | - Jaco Vangronsveld
- Environmental Biology, Hasselt University - Campus Diepenbeek, Agoralaan Building D, 3590 Diepenbeek Belgium
| | - Jan d'Haen
- IMO - IMOMEC, Hasselt University - Campus Diepenbeek, Wetenschapspark 1, 3590 Diepenbeek Belgium
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Hayter ML, Peterson CA. Can Ca2+ fluxes to the root xylem be sustained by Ca2+-ATPases in exodermal and endodermal plasma membranes? PLANT PHYSIOLOGY 2004; 136:4318-25. [PMID: 15531711 PMCID: PMC535861 DOI: 10.1104/pp.104.041889] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2004] [Revised: 06/09/2004] [Accepted: 06/10/2004] [Indexed: 05/24/2023]
Abstract
The pathway of Ca2+ movement from the soil solution into the root stele has been a subject of controversy. If transport through the endodermis is assumed to be through the cytoplasm, the limiting factor is believed to be the active pumping of Ca2+ from the cytoplasm into the stele apoplast through the plasma membrane lying on the stele side of the Casparian band. By analogy, for similar transport through the exodermis, the limiting step would be the active pumping into the apoplast on the central cortical side of the layer. Such effluxes are mediated by Ca2+-ATPases. To assess whether or not known Ca2+ fluxes to the stele in onion (Allium cepa) roots could be supported by Ca2+-ATPases, the percentages of total membrane protein particles required to effect the transport were calculated using measured values of membrane surface areas, an animal literature value for Ca2+-ATPase V(max), plant literature values for Ca2+-ATPase K(m), and protein densities of relevant membranes. Effects of a putative symplastic movement of Ca2+ from the exo- or endodermis into the next cell layer, which would increase the surface areas available for pumping, were also considered. Depending on the assumptions applied, densities of Ca2+ pumps, calculated as a percentage of total membrane protein particles, varied tremendously between three and 1,600 for the endodermis, and between 0.94 and 1,900 for the exodermis. On the basis of the data, the possibility of Ca2+ transport through the cytoplasm and membranes of the exodermis and endodermis cannot be discounted. Thus, it is premature to assign an entirely apoplastic pathway for Ca2+ movement from the soil solution to the tracheary elements of the xylem. To verify any conclusion with certainty, more detailed data are required for the characteristics of exo- and endodermal Ca2+-ATPases.
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Affiliation(s)
- Meghan L Hayter
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
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Storey R, Leigh RA. Processes modulating calcium distribution in citrus leaves. An investigation using x-ray microanalysis with strontium as a tracer. PLANT PHYSIOLOGY 2004; 136:3838-48. [PMID: 15516511 PMCID: PMC527180 DOI: 10.1104/pp.104.045674] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2004] [Revised: 06/05/2004] [Accepted: 06/07/2004] [Indexed: 05/18/2023]
Abstract
Citrus leaves accumulate large amounts of calcium that must be compartmented effectively to prevent stomatal closure by extracellular Ca2+ and interference with Ca(2+)-based cell signaling pathways. Using x-ray microanalysis, the distribution of calcium between vacuoles in different cell types of leaves of rough lemon (Citrus jambhiri Lush.) was investigated. Calcium was accumulated principally in palisade, spongy mesophyll, and crystal-containing idioblast cells. It was low in epidermal and bundle sheath cells. Potassium showed the reverse distribution. Rubidium and strontium were used as tracers to examine the pathways by which potassium and calcium reached these cells. Comparisons of strontium and calcium distribution indicated that strontium is a good tracer for calcium, but rubidium did not mirror the potassium distribution pattern. The amount of strontium accumulated was highest in palisade cells, lowest in bundle sheath and epidermal cells, and intermediate in the spongy mesophyll. Accumulation of strontium in palisade and spongy mesophyll was accompanied by loss of potassium from these cells and its accumulation in the bundle sheath. Strontium moved apoplastically from the xylem to all cell types, and manipulation of water loss from the adaxial leaf surface suggested that diffusion is responsible for strontium movement to this side of the leaf. The results highlight the importance of palisade and spongy mesophyll as repositories for calcium and suggest that calcium distribution between different cell types is the result of differential rates of uptake. This tracer technique can provide important information about the ion uptake and accumulation properties of cells in intact leaves.
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Affiliation(s)
- Richard Storey
- Horticulture Unit, Commonwealth Scientific and Industrial Research Organisation Plant Industry, Merbein, Victoria 3505, Australia.
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