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Liang X, Gao Y, Zhang X, Tian Y, Zhang Z, Gao L. Effect of optimal daily fertigation on migration of water and salt in soil, root growth and fruit yield of cucumber (Cucumis sativus L.) in solar-greenhouse. PLoS One 2014; 9:e86975. [PMID: 24475204 PMCID: PMC3903608 DOI: 10.1371/journal.pone.0086975] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 12/16/2013] [Indexed: 11/18/2022] Open
Abstract
Inappropriate and excessive irrigation and fertilization have led to the predominant decline of crop yields, and water and fertilizer use efficiency in intensive vegetable production systems in China. For many vegetables, fertigation can be applied daily according to the actual water and nutrient requirement of crops. A greenhouse study was therefore conducted to investigate the effect of daily fertigation on migration of water and salt in soil, and root growth and fruit yield of cucumber. The treatments included conventional interval fertigation, optimal interval fertigation and optimal daily fertigation. Generally, although soil under the treatment optimal interval fertigation received much lower fertilizers than soil under conventional interval fertigation, the treatment optimal interval fertigation did not statistically decrease the economic yield and fruit nutrition quality of cucumber when compare to conventional interval fertigation. In addition, the treatment optimal interval fertigation effectively avoided inorganic nitrogen accumulation in soil and significantly (P<0.05) increased the partial factor productivity of applied nitrogen by 88% and 209% in the early-spring and autumn-winter seasons, respectively, when compared to conventional interval fertigation. Although soils under the treatments optimal interval fertigation and optimal daily fertigation received the same amount of fertilizers, the treatment optimal daily fertigation maintained the relatively stable water, electrical conductivity and mineral nitrogen levels in surface soils, promoted fine root (<1.5 mm diameter) growth of cucumber, and eventually increased cucumber economic yield by 6.2% and 8.3% and partial factor productivity of applied nitrogen by 55% and 75% in the early-spring and autumn-winter seasons, respectively, when compared to the treatment optimal interval fertigation. These results suggested that optimal daily fertigation is a beneficial practice for improving crop yield and the water and fertilizers use efficiency in solar greenhouse.
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Affiliation(s)
- Xinshu Liang
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Science, China Agricultural University, Beijing, P.R. China
| | - Yinan Gao
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Science, China Agricultural University, Beijing, P.R. China
| | - Xiaoying Zhang
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Science, China Agricultural University, Beijing, P.R. China
| | - Yongqiang Tian
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Science, China Agricultural University, Beijing, P.R. China
| | - Zhenxian Zhang
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Science, China Agricultural University, Beijing, P.R. China
| | - Lihong Gao
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Science, China Agricultural University, Beijing, P.R. China
- * E-mail:
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302
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Namayanja A, Semoka J, Buruchara R, Nchimbi S, Waswa M. Genotypic Variation for Tolerance to Low Soil Phosphorous in Common Bean under Controlled Screen House Conditions. ACTA ACUST UNITED AC 2014. [DOI: 10.4236/as.2014.54030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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303
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Leitner D, Felderer B, Vontobel P, Schnepf A. Recovering root system traits using image analysis exemplified by two-dimensional neutron radiography images of lupine. PLANT PHYSIOLOGY 2014; 164:24-35. [PMID: 24218493 PMCID: PMC3875805 DOI: 10.1104/pp.113.227892] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 11/06/2013] [Indexed: 05/18/2023]
Abstract
Root system traits are important in view of current challenges such as sustainable crop production with reduced fertilizer input or in resource-limited environments. We present a novel approach for recovering root architectural parameters based on image-analysis techniques. It is based on a graph representation of the segmented and skeletonized image of the root system, where individual roots are tracked in a fully automated way. Using a dynamic root architecture model for deciding whether a specific path in the graph is likely to represent a root helps to distinguish root overlaps from branches and favors the analysis of root development over a sequence of images. After the root tracking step, global traits such as topological characteristics as well as root architectural parameters are computed. Analysis of neutron radiographic root system images of lupine (Lupinus albus) grown in mesocosms filled with sandy soil results in a set of root architectural parameters. They are used to simulate the dynamic development of the root system and to compute the corresponding root length densities in the mesocosm. The graph representation of the root system provides global information about connectivity inside the graph. The underlying root growth model helps to determine which path inside the graph is most likely for a given root. This facilitates the systematic investigation of root architectural traits, in particular with respect to the parameterization of dynamic root architecture models.
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Affiliation(s)
| | - Bernd Felderer
- University of Vienna, Computational Science Center, A–1090 Vienna, Austria (D.L.)
- Swiss Federal Institute of Technology in Zurich, Institute of Terrestrial, Ecosystems, CH–8092 Zurich, Switzerland (B.F.)
- Paul Scherrer Institute, Spallation Neutron Source Division CH–5232 Willigen, Switzerland (P.V.)
- Forschungszentrum Jülich, Agrosphere, D–52425 Julich, Germany (A.S.); and
- University of Natural Resources and Life Sciences, Vienna, Institute of Hydraulics and Rural Water Management, A–1190 Vienna, Austria (A.S.)
| | - Peter Vontobel
- University of Vienna, Computational Science Center, A–1090 Vienna, Austria (D.L.)
- Swiss Federal Institute of Technology in Zurich, Institute of Terrestrial, Ecosystems, CH–8092 Zurich, Switzerland (B.F.)
- Paul Scherrer Institute, Spallation Neutron Source Division CH–5232 Willigen, Switzerland (P.V.)
- Forschungszentrum Jülich, Agrosphere, D–52425 Julich, Germany (A.S.); and
- University of Natural Resources and Life Sciences, Vienna, Institute of Hydraulics and Rural Water Management, A–1190 Vienna, Austria (A.S.)
| | - Andrea Schnepf
- University of Vienna, Computational Science Center, A–1090 Vienna, Austria (D.L.)
- Swiss Federal Institute of Technology in Zurich, Institute of Terrestrial, Ecosystems, CH–8092 Zurich, Switzerland (B.F.)
- Paul Scherrer Institute, Spallation Neutron Source Division CH–5232 Willigen, Switzerland (P.V.)
- Forschungszentrum Jülich, Agrosphere, D–52425 Julich, Germany (A.S.); and
- University of Natural Resources and Life Sciences, Vienna, Institute of Hydraulics and Rural Water Management, A–1190 Vienna, Austria (A.S.)
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304
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Manoli A, Begheldo M, Genre A, Lanfranco L, Trevisan S, Quaggiotti S. NO homeostasis is a key regulator of early nitrate perception and root elongation in maize. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:185-200. [PMID: 24220653 PMCID: PMC3883287 DOI: 10.1093/jxb/ert358] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Crop plant development is strongly dependent on nitrogen availability in the soil and on the efficiency of its recruitment by roots. For this reason, the understanding of the molecular events underlying root adaptation to nitrogen fluctuations is a primary goal to develop biotechnological tools for sustainable agriculture. However, knowledge about molecular responses to nitrogen availability is derived mainly from the study of model species. Nitric oxide (NO) has been recently proposed to be implicated in plant responses to environmental stresses, but its exact role in the response of plants to nutritional stress is still under evaluation. In this work, the role of NO production by maize roots after nitrate perception was investigated by focusing on the regulation of transcription of genes involved in NO homeostasis and by measuring NO production in roots. Moreover, its involvement in the root growth response to nitrate was also investigated. The results provide evidence that NO is produced by nitrate reductase as an early response to nitrate supply and that the coordinated induction of non-symbiotic haemoglobins (nsHbs) could finely regulate the NO steady state. This mechanism seems to be implicated on the modulation of the root elongation in response to nitrate perception. Moreover, an improved agar-plate system for growing maize seedlings was developed. This system, which allows localized treatments to be performed on specific root portions, gave the opportunity to discern between localized and systemic effects of nitrate supply to roots.
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Affiliation(s)
- Alessandro Manoli
- Department of Agriculture, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padua, Agripolis, Viale dell’Università, 16, 35020 Legnaro (PD), Italy
| | - Maura Begheldo
- Department of Agriculture, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padua, Agripolis, Viale dell’Università, 16, 35020 Legnaro (PD), Italy
| | - Andrea Genre
- Department of Life Sciences and Systems Biology, University of Turin, Viale Mattioli 25, 10125 Turin, Italy
| | - Luisa Lanfranco
- Department of Life Sciences and Systems Biology, University of Turin, Viale Mattioli 25, 10125 Turin, Italy
| | - Sara Trevisan
- Department of Agriculture, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padua, Agripolis, Viale dell’Università, 16, 35020 Legnaro (PD), Italy
| | - Silvia Quaggiotti
- Department of Agriculture, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padua, Agripolis, Viale dell’Università, 16, 35020 Legnaro (PD), Italy
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305
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Jin K, Shen J, Ashton RW, Dodd IC, Parry MAJ, Whalley WR. How do roots elongate in a structured soil? JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:4761-4777. [PMID: 24043852 DOI: 10.1093/jxb/ert286] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In this review, we examine how roots penetrate a structured soil. We first examine the relationship between soil water status and its mechanical strength, as well as the ability of the soil to supply water to the root. We identify these as critical soil factors, because it is primarily in drying soil that mechanical constraints limit root elongation. Water supply to the root is important because root water status affects growth pressures and root stiffness. To simplify the bewildering complexity of soil-root interactions, the discussion is focused around the special cases of root elongation in soil with pores much smaller than the root diameter and the penetration of roots at interfaces within the soil. While it is often assumed that the former case is well understood, many unanswered questions remain. While low soil-root friction is often viewed as a trait conferring better penetration of strong soils, it may also increase the axial pressure on the root tip and in so doing reduce the rate of cell division and/or expansion. The precise trade-off between various root traits involved in root elongation in homogeneous soil remains to be determined. There is consensus that the most important factors determining root penetration at an interface are the angle at which the root attempts to penetrate the soil, root stiffness, and the strength of the soil to be penetrated. The effect of growth angle on root penetration implicates gravitropic responses in improved root penetration ability. Although there is no work that has explored the effect of the strength of the gravitropic responses on penetration of hard layers, we attempt to outline possible interactions. Impacts of soil drying and strength on phytohormone concentrations in roots, and consequent root-to-shoot signalling, are also considered.
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Affiliation(s)
- Kemo Jin
- Department of Plant Nutrition, College of Resource and Environmental Sciences, China Agricultural University, Beijing 100193, PR China
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306
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Miguel MA, Widrig A, Vieira RF, Brown KM, Lynch JP. Basal root whorl number: a modulator of phosphorus acquisition in common bean (Phaseolus vulgaris). ANNALS OF BOTANY 2013; 112:973-82. [PMID: 23925972 PMCID: PMC3783229 DOI: 10.1093/aob/mct164] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 06/03/2013] [Indexed: 05/18/2023]
Abstract
BACKGROUND AND AIMS Root architectural phenes enhancing topsoil foraging are important for phosphorus acquisition. In this study, the utility of a novel phene is described, basal root whorl number (BRWN), that has significant effects on topsoil foraging in common bean (Phaseolus vulgaris). METHODS Whorls are defined as distinct tiers of basal roots that emerge in a tetrarch fashion along the base of the hypocotyl. Wild and domesticated bean taxa as well as two recombinant inbred line (RIL) populations were screened for BRWN and basal root number (BRN). A set of six RILs contrasting for BRWN was evaluated for performance under low phosphorus availability in the greenhouse and in the field. In the greenhouse, plants were grown in a sand-soil media with low or high phosphorus availability. In the field, plants were grown in an Oxisol in Mozambique under low and moderate phosphorus availability. KEY RESULTS Wild bean accessions tended to have a BRWN of one or two, whereas cultivated accessions had BRWN reaching four and sometimes five. BRWN and BRN did not vary with phosphorus availability, i.e. BRWN was not a plastic trait in these genotypes. Greater BRWN was beneficial for phosphorus acquisition in low phosphorus soil. Genotypes with three whorls had almost twice the shoot biomass, greater root length and greater leaf area than related genotypes with two whorls. In low phosphorus soil, shoot phosphorus content was strongly correlated with BRWN (R(2) = 0.64 in the greenhouse and R(2) = 0.88 in the field). Genotypes with three whorls had shallower root systems with a greater range of basal root growth angles (from 10 to 45 ° from horizontal) than genotypes with two whorls (angles ranged from 60 to 85 ° from horizontal). CONCLUSIONS The results indicate that BRWN is associated with increased phosphorus acquisition and that this trait may have value for selection of genotypes with better performance in low phosphorus soils.
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Affiliation(s)
- M. A. Miguel
- Department of Plant Science, The Pennsylvania State University, University Park, PA 16802, USA
| | - A. Widrig
- Department of Plant Science, The Pennsylvania State University, University Park, PA 16802, USA
| | - R. F. Vieira
- Department of Plant Science, The Pennsylvania State University, University Park, PA 16802, USA
- Empresa de Pesquisa Agropecuária de Minas Gerais, Caixa Postal 216, CEP 36571-000 Viçosa, MG, Brazil
| | - K. M. Brown
- Department of Plant Science, The Pennsylvania State University, University Park, PA 16802, USA
| | - J. P. Lynch
- Department of Plant Science, The Pennsylvania State University, University Park, PA 16802, USA
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307
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York LM, Nord EA, Lynch JP. Integration of root phenes for soil resource acquisition. FRONTIERS IN PLANT SCIENCE 2013; 4:355. [PMID: 24062755 PMCID: PMC3771073 DOI: 10.3389/fpls.2013.00355] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Accepted: 08/23/2013] [Indexed: 05/17/2023]
Abstract
Suboptimal availability of water and nutrients is a primary limitation to plant growth in terrestrial ecosystems. The acquisition of soil resources by plant roots is therefore an important component of plant fitness and agricultural productivity. Plant root systems comprise a set of phenes, or traits, that interact. Phenes are the units of the plant phenotype, and phene states represent the variation in form and function a particular phene may take. Root phenes can be classified as affecting resource acquisition or utilization, influencing acquisition through exploration or exploitation, and in being metabolically influential or neutral. These classifications determine how one phene will interact with another phene, whether through foraging mechanisms or metabolic economics. Phenes that influence one another through foraging mechanisms are likely to operate within a phene module, a group of interacting phenes, that may be co-selected. Examples of root phene interactions discussed are: (1) root hair length × root hair density, (2) lateral branching × root cortical aerenchyma (RCA), (3) adventitious root number × adventitious root respiration and basal root growth angle (BRGA), (4) nodal root number × RCA, and (5) BRGA × root hair length and density. Progress in the study of phenes and phene interactions will be facilitated by employing simulation modeling and near-isophenic lines that allow the study of specific phenes and phene combinations within a common phenotypic background. Developing a robust understanding of the phenome at the organismal level will require new lines of inquiry into how phenotypic integration influences plant function in diverse environments. A better understanding of how root phenes interact to affect soil resource acquisition will be an important tool in the breeding of crops with superior stress tolerance and reduced dependence on intensive use of inputs.
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Affiliation(s)
- Larry M. York
- Intercollege Program in Ecology, The Pennsylvania State University, University ParkPA, USA
- Department of Plant Science, The Pennsylvania State University, University ParkPA, USA
| | - Eric A. Nord
- Intercollege Program in Ecology, The Pennsylvania State University, University ParkPA, USA
- Department of Plant Science, The Pennsylvania State University, University ParkPA, USA
| | - Jonathan P. Lynch
- Intercollege Program in Ecology, The Pennsylvania State University, University ParkPA, USA
- Department of Plant Science, The Pennsylvania State University, University ParkPA, USA
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308
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Postma JA, Schurr U, Fiorani F. Dynamic root growth and architecture responses to limiting nutrient availability: linking physiological models and experimentation. Biotechnol Adv 2013; 32:53-65. [PMID: 24012600 DOI: 10.1016/j.biotechadv.2013.08.019] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Revised: 08/28/2013] [Accepted: 08/29/2013] [Indexed: 11/28/2022]
Abstract
In recent years the study of root phenotypic plasticity in response to sub-optimal environmental factors and the genetic control of these responses have received renewed attention. As a path to increased productivity, in particular for low fertility soils, several applied research projects worldwide target the improvement of crop root traits both in plant breeding and biotechnology contexts. To assist these tasks and address the challenge of optimizing root growth and architecture for enhanced mineral resource use, the development of realistic simulation models is of great importance. We review this research field from a modeling perspective focusing particularly on nutrient acquisition strategies for crop production on low nitrogen and low phosphorous soils. Soil heterogeneity and the dynamics of nutrient availability in the soil pose a challenging environment in which plants have to forage efficiently for nutrients in order to maintain their internal nutrient homeostasis throughout their life cycle. Mathematical models assist in understanding plant growth strategies and associated root phenes that have potential to be tested and introduced in physiological breeding programs. At the same time, we stress that it is necessary to carefully consider model assumptions and development from a whole plant-resource allocation perspective and to introduce or refine modules simulating explicitly root growth and architecture dynamics through ontogeny with reference to key factors that constrain root growth. In this view it is important to understand negative feedbacks such as plant-plant competition. We conclude by briefly touching on available and developing technologies for quantitative root phenotyping from lab to field, from quantification of partial root profiles in the field to 3D reconstruction of whole root systems. Finally, we discuss how these approaches can and should be tightly linked to modeling to explore the root phenome.
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Affiliation(s)
- Johannes A Postma
- Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich, Leo Brandt Strasse, 52425 Jülich, Germany.
| | - Ulrich Schurr
- Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich, Leo Brandt Strasse, 52425 Jülich, Germany.
| | - Fabio Fiorani
- Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich, Leo Brandt Strasse, 52425 Jülich, Germany.
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309
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Haling RE, Brown LK, Bengough AG, Young IM, Hallett PD, White PJ, George TS. Root hairs improve root penetration, root-soil contact, and phosphorus acquisition in soils of different strength. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:3711-21. [PMID: 23861547 DOI: 10.1093/jxb/ert200] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Root hairs are a key trait for improving the acquisition of phosphorus (P) by plants. However, it is not known whether root hairs provide significant advantage for plant growth under combined soil stresses, particularly under conditions that are known to restrict root hair initiation or elongation (e.g. compacted or high-strength soils). To investigate this, the root growth and P uptake of root hair genotypes of barley, Hordeum vulgare L. (i.e. genotypes with and without root hairs), were assessed under combinations of P deficiency and high soil strength. Genotypes with root hairs were found to have an advantage for root penetration into high-strength layers relative to root hairless genotypes. In P-deficient soils, despite a 20% reduction in root hair length under high-strength conditions, genotypes with root hairs were also found to have an advantage for P uptake. However, in fertilized soils, root hairs conferred an advantage for P uptake in low-strength soil but not in high-strength soil. Improved root-soil contact, coupled with an increased supply of P to the root, may decrease the value of root hairs for P acquisition in high-strength, high-P soils. Nevertheless, this work demonstrates that root hairs are a valuable trait for plant growth and nutrient acquisition under combined soil stresses. Selecting plants with superior root hair traits is important for improving P uptake efficiency and hence the sustainability of agricultural systems.
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Affiliation(s)
- Rebecca E Haling
- School of Environmental and Rural Science, University of New England, Armidale, NSW 2351, Australia
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310
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Tian X, Doerner P. Root resource foraging: does it matter? FRONTIERS IN PLANT SCIENCE 2013; 4:303. [PMID: 23964282 PMCID: PMC3740241 DOI: 10.3389/fpls.2013.00303] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2013] [Accepted: 07/22/2013] [Indexed: 05/28/2023]
Affiliation(s)
- Xin Tian
- Institute for Molecular Plant Science, School of Biological Sciences, University of EdinburghEdinburgh, Scotland
| | - Peter Doerner
- Institute for Molecular Plant Science, School of Biological Sciences, University of EdinburghEdinburgh, Scotland
- Laboratoire de Physiologie Cellulaire Végétale, CNRS, CEA, INRA, Université Grenoble AlpesGrenoble, France
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311
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Faget M, Nagel KA, Walter A, Herrera JM, Jahnke S, Schurr U, Temperton VM. Root-root interactions: extending our perspective to be more inclusive of the range of theories in ecology and agriculture using in-vivo analyses. ANNALS OF BOTANY 2013; 112:253-66. [PMID: 23378521 PMCID: PMC3698385 DOI: 10.1093/aob/mcs296] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 11/23/2012] [Indexed: 05/19/2023]
Abstract
BACKGROUND There is a large body of literature on competitive interactions among plants, but many studies have only focused on above-ground interactions and little is known about root-root dynamics between interacting plants. The perspective on possible mechanisms that explain the outcome of root-root interactions has recently been extended to include non-resource-driven mechanisms (as well as resource-driven mechanisms) of root competition and positive interactions such as facilitation. These approaches have often suffered from being static, partly due to the lack of appropriate methodologies for in-situ non-destructive root characterization. SCOPE Recent studies show that interactive effects of plant neighbourhood interactions follow non-linear and non-additive paths that are hard to explain. Common outcomes such as accumulation of roots mainly in the topsoil cannot be explained solely by competition theory but require a more inclusive theoretical, as well as an improved methodological framework. This will include the question of whether we can apply the same conceptual framework to crop versus natural species. CONCLUSIONS The development of non-invasive methods to dynamically study root-root interactions in vivo will provide the necessary tools to study a more inclusive conceptual framework for root-root interactions. By following the dynamics of root-root interactions through time in a whole range of scenarios and systems, using a wide variety of non-invasive methods, (such as fluorescent protein which now allows us to separately identify the roots of several individuals within soil), we will be much better equipped to answer some of the key questions in root physiology, ecology and agronomy.
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Affiliation(s)
- Marc Faget
- Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, 52428 Jülich, Germany.
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312
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Jaramillo RE, Nord EA, Chimungu JG, Brown KM, Lynch JP. Root cortical burden influences drought tolerance in maize. ANNALS OF BOTANY 2013; 112:429-37. [PMID: 23618897 PMCID: PMC3698389 DOI: 10.1093/aob/mct069] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 02/07/2013] [Indexed: 05/18/2023]
Abstract
BACKGROUND AND AIMS Root cortical aerenchyma (RCA) increases water and nutrient acquisition by reducing the metabolic costs of soil exploration. In this study the hypothesis was tested that living cortical area (LCA; transversal root cortical area minus aerenchyma area and intercellular air space) is a better predictor of root respiration, soil exploration and, therefore, drought tolerance than RCA formation or root diameter. METHODS RCA, LCA, root respiration, root length and biomass loss in response to drought were evaluated in maize (Zea mays) recombinant inbred lines grown with adequate and suboptimal irrigation in soil mesocosms. KEY RESULTS Root respiration was highly correlated with LCA. LCA was a better predictor of root respiration than either RCA or root diameter. RCA reduced respiration of large-diameter roots. Since RCA and LCA varied in different parts of the root system, the effects of RCA and LCA on root length were complex. Greater crown-root LCA was associated with reduced crown-root length relative to total root length. Reduced LCA was associated with improved drought tolerance. CONCLUSIONS The results are consistent with the hypothesis that LCA is a driver of root metabolic costs and may therefore have adaptive significance for water acquisition in drying soil.
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Affiliation(s)
| | | | | | | | - Jonathan P. Lynch
- Department of Plant Science, The Pennsylvania State University, 102 Tyson Building, University Park, PA 16803, USA
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313
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Niu YF, Chai RS, Jin GL, Wang H, Tang CX, Zhang YS. Responses of root architecture development to low phosphorus availability: a review. ANNALS OF BOTANY 2013; 112:391-408. [PMID: 23267006 PMCID: PMC3698383 DOI: 10.1093/aob/mcs285] [Citation(s) in RCA: 211] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 11/14/2012] [Indexed: 05/17/2023]
Abstract
BACKGROUND Phosphorus (P) is an essential element for plant growth and development but it is often a limiting nutrient in soils. Hence, P acquisition from soil by plant roots is a subject of considerable interest in agriculture, ecology and plant root biology. Root architecture, with its shape and structured development, can be considered as an evolutionary response to scarcity of resources. SCOPE This review discusses the significance of root architecture development in response to low P availability and its beneficial effects on alleviation of P stress. It also focuses on recent progress in unravelling cellular, physiological and molecular mechanisms in root developmental adaptation to P starvation. The progress in a more detailed understanding of these mechanisms might be used for developing strategies that build upon the observed explorative behaviour of plant roots. CONCLUSIONS The role of root architecture in alleviation of P stress is well documented. However, this paper describes how plants adjust their root architecture to low-P conditions through inhibition of primary root growth, promotion of lateral root growth, enhancement of root hair development and cluster root formation, which all promote P acquisition by plants. The mechanisms for activating alterations in root architecture in response to P deprivation depend on changes in the localized P concentration, and transport of or sensitivity to growth regulators such as sugars, auxins, ethylene, cytokinins, nitric oxide (NO), reactive oxygen species (ROS) and abscisic acid (ABA). In the process, many genes are activated, which in turn trigger changes in molecular, physiological and cellular processes. As a result, root architecture is modified, allowing plants to adapt effectively to the low-P environment. This review provides a framework for understanding how P deficiency alters root architecture, with a focus on integrated physiological and molecular signalling.
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Affiliation(s)
- Yao Fang Niu
- Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Ru Shan Chai
- Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Gu Lei Jin
- College of Agronomy and Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Huan Wang
- Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Cai Xian Tang
- Centre for AgriBioscience/Department of Agricultural Sciences, La Trobe University, Melbourne Campus, Bundoora, Vic 3086, Australia
| | - Yong Song Zhang
- Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
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314
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Rose TJ, Impa SM, Rose MT, Pariasca-Tanaka J, Mori A, Heuer S, Johnson-Beebout SE, Wissuwa M. Enhancing phosphorus and zinc acquisition efficiency in rice: a critical review of root traits and their potential utility in rice breeding. ANNALS OF BOTANY 2013; 112:331-45. [PMID: 23071218 PMCID: PMC3698374 DOI: 10.1093/aob/mcs217] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 08/24/2012] [Indexed: 05/18/2023]
Abstract
BACKGROUND Rice is the world's most important cereal crop and phosphorus (P) and zinc (Zn) deficiency are major constraints to its production. Where fertilizer is applied to overcome these nutritional constraints it comes at substantial cost to farmers and the efficiency of fertilizer use is low. Breeding crops that are efficient at acquiring P and Zn from native soil reserves or fertilizer sources has been advocated as a cost-effective solution, but would benefit from knowledge of genes and mechanisms that confer enhanced uptake of these nutrients by roots. SCOPE This review discusses root traits that have been linked to P and Zn uptake in rice, including traits that increase mobilization of P/Zn from soils, increase the volume of soil explored by roots or root surface area to recapture solubilized nutrients, enhance the rate of P/Zn uptake across the root membrane, and whole-plant traits that affect root growth and nutrient capture. In particular, this review focuses on the potential for these traits to be exploited through breeding programmes to produce nutrient-efficient crop cultivars. CONCLUSIONS Few root traits have so far been used successfully in plant breeding for enhanced P and Zn uptake in rice or any other crop. Insufficient genotypic variation for traits or the failure to enhance nutrient uptake under realistic field conditions are likely reasons for the limited success. More emphasis is needed on field studies in mapping populations or association panels to identify those traits and underlying genes that are able to enhance nutrient acquisition beyond the level already present in most cultivars.
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Affiliation(s)
- T. J. Rose
- Southern Cross Plant Science, Southern Cross University, PO Box 157, Lismore, NSW 2480, Australia
| | - S. M. Impa
- Crop and Environmental Sciences Division, International Rice Research Institute (IRRI), DAPO Bob 7777, Metro Manila, Philippines
| | - M. T. Rose
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
| | - J. Pariasca-Tanaka
- Japan International Research Center for Agricultural Sciences (JIRCAS), Stable Food Production Program, 1-1 Ohwashi Tsukuba, Ibaraki 305-8686, Japan
| | - A. Mori
- Japan International Research Center for Agricultural Sciences (JIRCAS), Stable Food Production Program, 1-1 Ohwashi Tsukuba, Ibaraki 305-8686, Japan
| | - S. Heuer
- Plant Breeding, Genetics and Biotechnology Division, International Rice Research Institute (IRRI), DAPO Bob 7777, Metro Manila, Philippines
| | - S. E. Johnson-Beebout
- Crop and Environmental Sciences Division, International Rice Research Institute (IRRI), DAPO Bob 7777, Metro Manila, Philippines
| | - M. Wissuwa
- Japan International Research Center for Agricultural Sciences (JIRCAS), Stable Food Production Program, 1-1 Ohwashi Tsukuba, Ibaraki 305-8686, Japan
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315
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White PJ, George TS, Gregory PJ, Bengough AG, Hallett PD, McKenzie BM. Matching roots to their environment. ANNALS OF BOTANY 2013; 112:207-22. [PMID: 23821619 PMCID: PMC3698393 DOI: 10.1093/aob/mct123] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 02/28/2013] [Indexed: 05/03/2023]
Abstract
BACKGROUND Plants form the base of the terrestrial food chain and provide medicines, fuel, fibre and industrial materials to humans. Vascular land plants rely on their roots to acquire the water and mineral elements necessary for their survival in nature or their yield and nutritional quality in agriculture. Major biogeochemical fluxes of all elements occur through plant roots, and the roots of agricultural crops have a significant role to play in soil sustainability, carbon sequestration, reducing emissions of greenhouse gasses, and in preventing the eutrophication of water bodies associated with the application of mineral fertilizers. SCOPE This article provides the context for a Special Issue of Annals of Botany on 'Matching Roots to Their Environment'. It first examines how land plants and their roots evolved, describes how the ecology of roots and their rhizospheres contributes to the acquisition of soil resources, and discusses the influence of plant roots on biogeochemical cycles. It then describes the role of roots in overcoming the constraints to crop production imposed by hostile or infertile soils, illustrates root phenotypes that improve the acquisition of mineral elements and water, and discusses high-throughput methods to screen for these traits in the laboratory, glasshouse and field. Finally, it considers whether knowledge of adaptations improving the acquisition of resources in natural environments can be used to develop root systems for sustainable agriculture in the future.
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316
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Lemaire L, Deleu C, Le Deunff E. Modulation of ethylene biosynthesis by ACC and AIB reveals a structural and functional relationship between the K15NO3 uptake rate and root absorbing surfaces. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:2725-37. [PMID: 23811694 DOI: 10.1093/jxb/ert124] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The modification of root traits in relation to nitrate uptake represents a source for improvement of nitrogen uptake efficiency. Because ethylene signalling modulates growth of exploratory and root hair systems more rapidly (minutes to hours) than nitrate signalling (days to weeks), a pharmacological approach was used to decipher the relationships between root elongation and N uptake. Rape seedlings were grown on agar plates supplied with 1mM K(15)NO3 and treated with different concentrations of either the ethylene precursor, ACC (0.1, 1, and 10 μM) or an inhibitor of ethylene biosynthesis, AIB (0.5 and 1 μM). The results showed that rapid modulation of root elongation (up to 8-fold) is more dependent on the ethylene than the nitrate signal. Indeed, ACC treatment induced a partial compensatory increase in (15)N uptake associated with overexpression of the BnNRT2.1 and BnNRT1.1 genes. Likewise, daily root elongation between treatments was not associated with daily nitrate uptake but was correlated with N status. This suggested that a part of the daily root response was modulated by cross talks between ethylene signalling and N and C metabolisms. This was confirmed by the reduction in C allocation to the roots induced by ACC treatment and the correlations of changes in the root length and shoot surface area with the aspartate content. The observed effects of ethylene signalling in the root elongation and NRT gene expression are discussed in the context of the putative role of NRT2.1 and NRT1.1 transporters as nitrate sensors.
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Affiliation(s)
- Lucile Lemaire
- Université de Caen Basse-Normandie, UMR EVA, F-14032 Caen cedex, France
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317
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Lynch JP. Steep, cheap and deep: an ideotype to optimize water and N acquisition by maize root systems. ANNALS OF BOTANY 2013; 112:347-57. [PMID: 23328767 PMCID: PMC3698384 DOI: 10.1093/aob/mcs293] [Citation(s) in RCA: 525] [Impact Index Per Article: 47.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Accepted: 11/21/2012] [Indexed: 05/17/2023]
Abstract
BACKGROUND A hypothetical ideotype is presented to optimize water and N acquisition by maize root systems. The overall premise is that soil resource acquisition is optimized by the coincidence of root foraging and resource availability in time and space. Since water and nitrate enter deeper soil strata over time and are initially depleted in surface soil strata, root systems with rapid exploitation of deep soil would optimize water and N capture in most maize production environments. • THE IDEOTYPE: Specific phenes that may contribute to rooting depth in maize include (a) a large diameter primary root with few but long laterals and tolerance of cold soil temperatures, (b) many seminal roots with shallow growth angles, small diameter, many laterals, and long root hairs, or as an alternative, an intermediate number of seminal roots with steep growth angles, large diameter, and few laterals coupled with abundant lateral branching of the initial crown roots, (c) an intermediate number of crown roots with steep growth angles, and few but long laterals, (d) one whorl of brace roots of high occupancy, having a growth angle that is slightly shallower than the growth angle for crown roots, with few but long laterals, (e) low cortical respiratory burden created by abundant cortical aerenchyma, large cortical cell size, an optimal number of cells per cortical file, and accelerated cortical senescence, (f) unresponsiveness of lateral branching to localized resource availability, and (g) low K(m) and high Vmax for nitrate uptake. Some elements of this ideotype have experimental support, others are hypothetical. Despite differences in N distribution between low-input and commercial maize production, this ideotype is applicable to low-input systems because of the importance of deep rooting for water acquisition. Many features of this ideotype are relevant to other cereal root systems and more generally to root systems of dicotyledonous crops.
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Affiliation(s)
- Jonathan P Lynch
- Department of Plant Science, The Pennsylvania State University, University Park, PA 16802, USA.
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318
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Brown LK, George TS, Dupuy LX, White PJ. A conceptual model of root hair ideotypes for future agricultural environments: what combination of traits should be targeted to cope with limited P availability? ANNALS OF BOTANY 2013; 112:317-30. [PMID: 23172412 PMCID: PMC3698376 DOI: 10.1093/aob/mcs231] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Accepted: 09/21/2012] [Indexed: 05/17/2023]
Abstract
BACKGROUND Phosphorus (P) often limits crop production and is frequently applied as fertilizer; however, supplies of quality rock phosphate for fertilizer production are diminishing. Plants have evolved many mechanisms to increase their P acquisition, and an understanding of these traits could result in improved long-term sustainability of agriculture. This Viewpoint focuses on the potential benefits of root hairs to sustainable production. SCOPE First the various root-related traits that could be deployed to improve agricultural sustainability are catalogued, and their potential costs and benefits to the plant are discussed. A novel mathematical model describing the effects of length, density and longevity of root hairs on P acquisition is developed, and the relative benefits of these three root-hair traits to plant P nutrition are calculated. Insights from this model are combined with experimental data to assess the relative benefits of a range of root hair ideotypes for sustainability of agriculture. CONCLUSIONS A cost-benefit analysis of root traits suggests that root hairs have the greatest potential for P acquisition relative to their cost of production. The novel modelling of root hair development indicates that the greatest gains in P-uptake efficiency are likely to be made through increased length and longevity of root hairs rather than by increasing their density. Synthesizing this information with that from published experiments we formulate six potential ideotypes to improve crop P acquisition. These combine appropriate root hair phenotypes with architectural, anatomical and biochemical traits, such that more root-hair zones are produced in surface soils, where P resources are found, on roots which are metabolically cheap to construct and maintain, and that release more P-mobilizing exudates. These ideotypes could be used to inform breeding programmes to enhance agricultural sustainability.
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Affiliation(s)
| | - T. S. George
- The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK
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319
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Shi L, Shi T, Broadley MR, White PJ, Long Y, Meng J, Xu F, Hammond JP. High-throughput root phenotyping screens identify genetic loci associated with root architectural traits in Brassica napus under contrasting phosphate availabilities. ANNALS OF BOTANY 2013; 112:381-9. [PMID: 23172414 PMCID: PMC3698377 DOI: 10.1093/aob/mcs245] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 09/25/2012] [Indexed: 05/18/2023]
Abstract
BACKGROUND AND AIMS Phosphate (Pi) deficiency in soils is a major limiting factor for crop growth worldwide. Plant growth under low Pi conditions correlates with root architectural traits and it may therefore be possible to select these traits for crop improvement. The aim of this study was to characterize root architectural traits, and to test quantitative trait loci (QTL) associated with these traits, under low Pi (LP) and high Pi (HP) availability in Brassica napus. METHODS Root architectural traits were characterized in seedlings of a double haploid (DH) mapping population (n = 190) of B. napus ['Tapidor' × 'Ningyou 7' (TNDH)] using high-throughput phenotyping methods. Primary root length (PRL), lateral root length (LRL), lateral root number (LRN), lateral root density (LRD) and biomass traits were measured 12 d post-germination in agar at LP and HP. KEY RESULTS In general, root and biomass traits were highly correlated under LP and HP conditions. 'Ningyou 7' had greater LRL, LRN and LRD than 'Tapidor', at both LP and HP availability, but smaller PRL. A cluster of highly significant QTL for LRN, LRD and biomass traits at LP availability were identified on chromosome A03; QTL for PRL were identified on chromosomes A07 and C06. CONCLUSIONS High-throughput phenotyping of Brassica can be used to identify root architectural traits which correlate with shoot biomass. It is feasible that these traits could be used in crop improvement strategies. The identification of QTL linked to root traits under LP and HP conditions provides further insights on the genetic basis of plant tolerance to P deficiency, and these QTL warrant further dissection.
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Affiliation(s)
- Lei Shi
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Taoxiong Shi
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Martin R. Broadley
- Plant and Crop Sciences Division, School of Biosciences, Sutton Bonington Campus, University of Nottingham, Loughborough LE12 5RD, UK
| | | | - Yan Long
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Jinling Meng
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Fangsen Xu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - John P. Hammond
- School of Plant Biology and Institute of Agriculture, University of Western Australia, Crawley, WA 6009, Australia
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320
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Zhang H, Zhu Y, Chen H. Root growth model: a novel approach to numerical function optimization and simulation of plant root system. Soft comput 2013. [DOI: 10.1007/s00500-013-1073-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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321
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Shelley IJ, Nishiuchi S, Shibata K, Inukai Y. SLL1, which encodes a member of the stearoyl-acyl carrier protein fatty acid desaturase family, is involved in cell elongation in lateral roots via regulation of fatty acid content in rice. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2013; 207:12-17. [PMID: 23602094 DOI: 10.1016/j.plantsci.2013.01.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 01/02/2013] [Accepted: 01/09/2013] [Indexed: 06/02/2023]
Abstract
We have identified a gene, SHORT LATERAL ROOT LENGTH1 (SLL1), which is important for the elongation of lateral roots in rice. An sll1 mutant has decreased lateral root growth due to a defect in the cell elongation. The SLL1 gene encodes a member of the stearoyl-acyl carrier protein fatty acid desaturase family that is the key regulator of overall fatty acid desaturation in plants. We measured the fatty acid content and found that the 18:0 content in the sll1 mutant root was approximately 4 times that in the wild-type root. When the sll1 mutant was grown at 33 °C, it complemented the mutant phenotype to a moderate level, which reflects the importance of the low 18:0 content in maintaining the cell membrane structure. The SLL1 gene was expressed at the lateral root tip, whereas SLL1 expression was not detected in the elongation zone of the crown roots. These results indicate that the lateral root specific defect in sll1 mutant is caused by the different expression patterns of SLL1 in lateral and crown roots. In addition, SLL1 over-expressers produced significantly longer lateral roots compared to the wild-type, and thus SLL1 gene would be very useful for improving rice root architecture.
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Affiliation(s)
- Israt Jahan Shelley
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan.
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322
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Screening for Barley Waterlogging Tolerance in Nordic Barley Cultivars (Hordeum vulgare L.) Using Chlorophyll Fluorescence on Hydroponically-Grown Plants. AGRONOMY-BASEL 2013. [DOI: 10.3390/agronomy3020376] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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323
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Chen L, Dodd IC, Theobald JC, Belimov AA, Davies WJ. The rhizobacterium Variovorax paradoxus 5C-2, containing ACC deaminase, promotes growth and development of Arabidopsis thaliana via an ethylene-dependent pathway. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:1565-73. [PMID: 23404897 PMCID: PMC3617834 DOI: 10.1093/jxb/ert031] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Many plant-growth-promoting rhizobacteria (PGPR) associated with plant roots contain the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase and can metabolize ACC, the immediate precursor of the plant hormone ethylene, thereby decreasing plant ethylene production and increasing plant growth. However, relatively few studies have explicitly linked ethylene emission and/or action to growth promotion in these plant-microbe interactions. This study examined effects of the PGPR Variovorax paradoxus 5C-2 containing ACC deaminase on the growth and development of Arabidopsis thaliana using wild-type (WT) plants and several ethylene-related mutants (etr1-1, ein2-1, and eto1-1). Soil inoculation with V. paradoxus 5C-2 promoted growth (leaf area and shoot biomass) of WT plants and the ethylene-overproducing mutant eto1-1, and also enhanced floral initiation of WT plants by 2.5 days. However, these effects were not seen in ethylene-insensitive mutants (etr1-1 and ein2-1) even though bacterial colonization of the root system was similar. Furthermore, V. paradoxus 5C-2 decreased ACC concentrations of rosette leaves of WT plants by 59% and foliar ethylene emission of both WT plants and eto1-1 mutants by 42 and 37%, respectively. Taken together, these results demonstrate that a fully functional ethylene signal transduction pathway is required for V. paradoxus 5C-2 to stimulate leaf growth and flowering of A. thaliana.
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Affiliation(s)
- Lin Chen
- The Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK
| | - Ian C. Dodd
- The Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK
- * To whom correspondence should be addressed. E-mail:
| | - Julian C. Theobald
- The Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK
| | - Andrey A. Belimov
- All-Russia Research Institute for Agricultural Microbiology, Podbelskogo Sh. 3, Pushkin-8, 196608, Saint Petersburg, Russian Federation
| | - William J. Davies
- The Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK
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324
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Gregory PJ, Atkinson CJ, Bengough AG, Else MA, Fernández-Fernández F, Harrison RJ, Schmidt S. Contributions of roots and rootstocks to sustainable, intensified crop production. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:1209-22. [PMID: 23378378 DOI: 10.1093/jxb/ers385] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Sustainable intensification is seen as the main route for meeting the world's increasing demands for food and fibre. As demands mount for greater efficiency in the use of resources to achieve this goal, so the focus on roots and rootstocks and their role in acquiring water and nutrients, and overcoming pests and pathogens, is increasing. The purpose of this review is to explore some of the ways in which understanding root systems and their interactions with soils could contribute to the development of more sustainable systems of intensive production. Physical interactions with soil particles limit root growth if soils are dense, but root-soil contact is essential for optimal growth and uptake of water and nutrients. X-ray microtomography demonstrated that maize roots elongated more rapidly with increasing root-soil contact, as long as mechanical impedance was not limiting root elongation, while lupin was less sensitive to changes in root-soil contact. In addition to selecting for root architecture and rhizosphere properties, the growth of many plants in cultivated systems is profoundly affected by selection of an appropriate rootstock. Several mechanisms for scion control by rootstocks have been suggested, but the causal signals are still uncertain and may differ between crop species. Linkage map locations for quantitative trait loci for disease resistance and other traits of interest in rootstock breeding are becoming available. Designing root systems and rootstocks for specific environments is becoming a feasible target.
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Affiliation(s)
- Peter J Gregory
- East Malling Research, New Road, East Malling, Kent ME19 6BJ, UK
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325
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Shen J, Li C, Mi G, Li L, Yuan L, Jiang R, Zhang F. Maximizing root/rhizosphere efficiency to improve crop productivity and nutrient use efficiency in intensive agriculture of China. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:1181-92. [PMID: 23255279 DOI: 10.1093/jxb/ers342] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Root and rhizosphere research has been conducted for many decades, but the underlying strategy of root/rhizosphere processes and management in intensive cropping systems remain largely to be determined. Improved grain production to meet the food demand of an increasing population has been highly dependent on chemical fertilizer input based on the traditionally assumed notion of 'high input, high output', which results in overuse of fertilizers but ignores the biological potential of roots or rhizosphere for efficient mobilization and acquisition of soil nutrients. Root exploration in soil nutrient resources and root-induced rhizosphere processes plays an important role in controlling nutrient transformation, efficient nutrient acquisition and use, and thus crop productivity. The efficiency of root/rhizosphere in terms of improved nutrient mobilization, acquisition, and use can be fully exploited by: (1) manipulating root growth (i.e. root development and size, root system architecture, and distribution); (2) regulating rhizosphere processes (i.e. rhizosphere acidification, organic anion and acid phosphatase exudation, localized application of nutrients, rhizosphere interactions, and use of efficient crop genotypes); and (3) optimizing root zone management to synchronize root growth and soil nutrient supply with demand of nutrients in cropping systems. Experiments have shown that root/rhizosphere management is an effective approach to increase both nutrient use efficiency and crop productivity for sustainable crop production. The objectives of this paper are to summarize the principles of root/rhizosphere management and provide an overview of some successful case studies on how to exploit the biological potential of root system and rhizosphere processes to improve crop productivity and nutrient use efficiency.
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Affiliation(s)
- Jianbo Shen
- Centre of Resources, Environment and Food Security, Department of Plant Nutrition, China Agricultural University, Beijing 100193, China
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326
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Lambers H, Clements JC, Nelson MN. How a phosphorus-acquisition strategy based on carboxylate exudation powers the success and agronomic potential of lupines (Lupinus, Fabaceae). AMERICAN JOURNAL OF BOTANY 2013; 100:263-88. [PMID: 23347972 DOI: 10.3732/ajb.1200474] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Lupines (Lupinus species; Fabaceae) are an ancient crop with great potential to be developed further for high-protein feed and food, cover crops, and phytoremediation. Being legumes, they are capable of symbiotically fixing atmospheric nitrogen. However, Lupinus species appear to be nonmycorrhizal or weakly mycorrhizal at most; instead some produce cluster roots, which release vast amounts of phosphate-mobilizing carboxylates (inorganic anions). Other lupines produce cluster-like roots, which function in a similar manner, and some release large amounts of carboxylates without specialized roots. These traits associated with nutrient acquisition make lupines ideally suited for either impoverished soils or soils with large amounts of phosphorus that is poorly available for most plants, e.g., acidic or alkaline soils. Here we explore how common the nonmycorrhizal phosphorus-acquisition strategy based on exudation of carboxylates is in the genus Lupinus, concluding it is very likely more widespread than generally acknowledged. This trait may partly account for the role of lupines as pioneers or invasive species, but also makes them suitable crop plants while we reach "peak phosphorus".
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Affiliation(s)
- Hans Lambers
- School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia.
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327
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Vosátka M, Látr A, Gianinazzi S, Albrechtová J. Development of arbuscular mycorrhizal biotechnology and industry: current achievements and bottlenecks. Symbiosis 2013. [DOI: 10.1007/s13199-012-0208-9] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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328
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Niu Y, Chai R, Dong H, Wang H, Tang C, Zhang Y. Effect of elevated CO₂ on phosphorus nutrition of phosphate-deficient Arabidopsis thaliana (L.) Heynh under different nitrogen forms. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:355-67. [PMID: 23183255 PMCID: PMC3528041 DOI: 10.1093/jxb/ers341] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Phosphorus (P) nutrition is always a key issue regarding plants responses to elevated CO(2). Yet it is unclear of how elevated CO(2) affects P uptake under different nitrogen (N) forms. This study investigated the influence of elevated CO(2) (800 µl l(-1)) on P uptake and utilization by Arabidopsis grown in pH-buffered phosphate (P)-deficient (0.5 µM) hydroponic culture supplying with 2mM nitrate (NO(3)(-)) or ammonium (NH(4)(+)). After 7 d treatment, elevated CO(2) enhanced the biomass production of both NO(3)(-)- and NH(4) (+)-fed plants but decreased the P amount absorbed per weight of roots and the P concentration in the shoots of plants supplied with NH(4)(+). In comparison, elevated CO(2) increased the amount of P absorbed per weight of roots, as well as the P concentration in plants and alleviated P deficiency-induced symptoms of plants supplied with NO(3)(-). Elevated CO(2) also increased the root/shoot ratio, total root surface area, and acid phosphatase activity, and enhanced the expression of genes or transcriptional factors involving in P uptake, allocation and remobilization in P deficient plants. Furthermore, elevated CO(2) increased the nitric oxide (NO) level in roots of NO(3)(-)-fed plants but decreased it in NH(4)(+)-fed plants. NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) inhibited plant P acquisition by roots under elevated CO(2). Considering all of these findings, this study concluded that a combination of elevated CO(2) and NO(3)(-) nutrition can induce a set of plant adaptive strategies to improve P status from P-deficient soluble sources and that NO may be a signalling molecule that controls these processes.
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Affiliation(s)
- Yaofang Niu
- Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Rushan Chai
- Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Huifen Dong
- Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Huan Wang
- Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Caixian Tang
- Department of Agricultural Sciences/Centre for AgriBioscience, La Trobe University, Melbourne Campus, Vic 3086, Australia
| | - Yongsong Zhang
- Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
- Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
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329
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White PJ, George TS, Dupuy LX, Karley AJ, Valentine TA, Wiesel L, Wishart J. Root traits for infertile soils. FRONTIERS IN PLANT SCIENCE 2013; 4:193. [PMID: 23781228 PMCID: PMC3678079 DOI: 10.3389/fpls.2013.00193] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 05/24/2013] [Indexed: 05/18/2023]
Abstract
Crop production is often restricted by the availability of essential mineral elements. For example, the availability of N, P, K, and S limits low-input agriculture, the phytoavailability of Fe, Zn, and Cu limits crop production on alkaline and calcareous soils, and P, Mo, Mg, Ca, and K deficiencies, together with proton, Al and Mn toxicities, limit crop production on acid soils. Since essential mineral elements are acquired by the root system, the development of crop genotypes with root traits increasing their acquisition should increase yields on infertile soils. This paper examines root traits likely to improve the acquisition of these elements and observes that, although the efficient acquisition of a particular element requires a specific set of root traits, suites of traits can be identified that benefit the acquisition of a group of mineral elements. Elements can be divided into three Groups based on common trait requirements. Group 1 comprises N, S, K, B, and P. Group 2 comprises Fe, Zn, Cu, Mn, and Ni. Group 3 contains mineral elements that rarely affect crop production. It is argued that breeding for a limited number of distinct root ideotypes, addressing particular combinations of mineral imbalances, should be pursued.
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Affiliation(s)
- Philip J. White
- The James Hutton InstituteInvergowrie, UK
- *Correspondence: Philip J. White, The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK e-mail:
| | | | | | | | | | - Lea Wiesel
- The James Hutton InstituteInvergowrie, UK
| | - Jane Wishart
- School of Biology, University of St. AndrewsSt. Andrews, UK
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330
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Nagel KA, Putz A, Gilmer F, Heinz K, Fischbach A, Pfeifer J, Faget M, Blossfeld S, Ernst M, Dimaki C, Kastenholz B, Kleinert AK, Galinski A, Scharr H, Fiorani F, Schurr U. GROWSCREEN-Rhizo is a novel phenotyping robot enabling simultaneous measurements of root and shoot growth for plants grown in soil-filled rhizotrons. FUNCTIONAL PLANT BIOLOGY : FPB 2012; 39:891-904. [PMID: 32480839 DOI: 10.1071/fp12023] [Citation(s) in RCA: 165] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2012] [Accepted: 04/14/2012] [Indexed: 05/21/2023]
Abstract
Root systems play an essential role in ensuring plant productivity. Experiments conducted in controlled environments and simulation models suggest that root geometry and responses of root architecture to environmental factors should be studied as a priority. However, compared with aboveground plant organs, roots are not easily accessible by non-invasive analyses and field research is still based almost completely on manual, destructive methods. Contributing to reducing the gap between laboratory and field experiments, we present a novel phenotyping system (GROWSCREEN-Rhizo), which is capable of automatically imaging roots and shoots of plants grown in soil-filled rhizotrons (up to a volume of ~18L) with a throughput of 60 rhizotrons per hour. Analysis of plants grown in this setup is restricted to a certain plant size (up to a shoot height of 80cm and root-system depth of 90cm). We performed validation experiments using six different species and for barley and maize, we studied the effect of moderate soil compaction, which is a relevant factor in the field. First, we found that the portion of root systems that is visible through the rhizotrons' transparent plate is representative of the total root system. The percentage of visible roots decreases with increasing average root diameter of the plant species studied and depends, to some extent, on environmental conditions. Second, we could measure relatively minor changes in root-system architecture induced by a moderate increase in soil compaction. Taken together, these findings demonstrate the good potential of this methodology to characterise root geometry and temporal growth responses with relatively high spatial accuracy and resolution for both monocotyledonous and dicotyledonous species. Our prototype will allow the design of high-throughput screening methodologies simulating environmental scenarios that are relevant in the field and will support breeding efforts towards improved resource use efficiency and stability of crop yields.
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Affiliation(s)
- Kerstin A Nagel
- Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Alexander Putz
- Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Frank Gilmer
- Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Kathrin Heinz
- Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Andreas Fischbach
- Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Johannes Pfeifer
- Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Marc Faget
- Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Stephan Blossfeld
- Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Michaela Ernst
- Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Chryssa Dimaki
- Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Bernd Kastenholz
- Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Ann-Katrin Kleinert
- Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Anna Galinski
- Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Hanno Scharr
- Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Fabio Fiorani
- Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Ulrich Schurr
- Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
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331
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Vinod KK, Heuer S. Approaches towards nitrogen- and phosphorus-efficient rice. AOB PLANTS 2012; 2012:pls028. [PMID: 23115710 PMCID: PMC3484362 DOI: 10.1093/aobpla/pls028] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 09/03/2012] [Indexed: 05/18/2023]
Abstract
BACKGROUND AND AIMS Food production has to increase to meet the demand of a growing population. In light of the high energy costs and increasingly scarce resources, future agricultural systems have to be more productive and more efficient in terms of inputs such as fertilizer and water. The development of rice varieties with high yield under low-nutrient conditions has therefore become a breeding priority. The rapid progress made in sequencing and molecular-marker technology is now beginning to change the way breeding is done, providing new opportunities. SCOPE Nitrogen (N) and phosphorus (P) are applied to agricultural systems in large quantities and a deficiency of either nutrient leads to yield losses and triggers complex molecular and physiological responses. The underlying genes are now being identified and studied in detail, and an increasing number of quantitative trait loci (QTLs) related to N and P uptake and utilization are being reported. Here, we provide an overview of the different aspects related to N and P in rice production systems, and apply a breeder's perspective on the potential of relevant genes and pathways for breeding applications. MAIN POINTS For the development of nutrient-efficient rice, a holistic approach should be followed combining optimized fertilizer management with enhanced nutrient uptake via a vigorous root system, leading to increased grain filling and yield. Despite an increasing number of N- and P-related genes and QTLs being reported, very few are actively used in molecular breeding programmes. The complex regulation of N- and P-related pathways challenges breeders and the research community to identify large-effect genes/QTLs. For this it will be important to focus more on the analysis of tolerant genotypes rather than model plants, since tolerance pathways may employ a different set of genes.
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Affiliation(s)
- K. K. Vinod
- Indian Agricultural Research Institute, New Delhi, India
| | - Sigrid Heuer
- International Rice Research Institute, Los Baños, Philippines
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332
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Nutrient Management in Support of Environmental and Agricultural Sustainability. SUSTAINABILITY 2012. [DOI: 10.3390/su4102513] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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333
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Jain A, Nagarajan VK, Raghothama KG. Transcriptional regulation of phosphate acquisition by higher plants. Cell Mol Life Sci 2012; 69:3207-24. [PMID: 22899310 PMCID: PMC11114959 DOI: 10.1007/s00018-012-1090-6] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Revised: 07/09/2012] [Accepted: 07/09/2012] [Indexed: 01/27/2023]
Abstract
Phosphorus (P), an essential macronutrient required for plant growth and development, is often limiting in natural and agro-climatic environments. To cope with heterogeneous or low phosphate (Pi) availability, plants have evolved an array of adaptive responses facilitating optimal acquisition and distribution of Pi. The root system plays a pivotal role in Pi-deficiency-mediated adaptive responses that are regulated by a complex interplay of systemic and local Pi sensing. Cross-talk with sugar, phytohormones, and other nutrient signaling pathways further highlight the intricacies involved in maintaining Pi homeostasis. Transcriptional regulation of Pi-starvation responses is particularly intriguing and involves a host of transcription factors (TFs). Although PHR1 of Arabidopsis is an extensively studied MYB TF regulating subset of Pi-starvation responses, it is not induced during Pi deprivation. Genome-wide analyses of Arabidopsis have shown that low Pi stress triggers spatiotemporal expression of several genes encoding different TFs. Functional characterization of some of these TFs reveals their diverse roles in regulating root system architecture, and acquisition and utilization of Pi. Some of the TFs are also involved in phytohormone-mediated root responses to Pi starvation. The biological roles of these TFs in transcriptional regulation of Pi homeostasis in model plants Arabidopsis thaliana and Oryza sativa are presented in this review.
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Affiliation(s)
- Ajay Jain
- National Research Centre on Plant Biotechnology, PUSA Campus, New Delhi, India.
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334
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Cai H, Chen F, Mi G, Zhang F, Maurer HP, Liu W, Reif JC, Yuan L. Mapping QTLs for root system architecture of maize (Zea mays L.) in the field at different developmental stages. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2012; 125:1313-24. [PMID: 22718302 DOI: 10.1007/s00122-012-1915-6] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Accepted: 06/05/2012] [Indexed: 05/21/2023]
Abstract
Root system architecture (RSA) is seldom considered as a selection criterion to improve yield in maize breeding, mainly because of the practical difficulties with their evaluation under field conditions. In the present study, phenotypic profiling of 187 advanced-backcross BC(4)F(3) maize lines (Ye478 × Wu312) was conducted at different developmental stages under field conditions at two locations (Dongbeiwang in 2007 and Shangzhuang in 2008) for five quantitative root traits. The aims were to (1) understand the genetic basis of root growth in the field; (2) investigate the contribution of root traits to grain yield (GY); and (3) detect QTLs controlling root traits at the seedling (I), silking (II) and maturation (III) stages. Axial root (AR)-related traits showed higher heritability than lateral root (LR)-related traits, which indicated stronger environmental effects on LR growth. Among the three developmental stages, root establishment at stage I showed the closest relationship with GY (r = 0.33-0.43, P < 0.001). Thirty QTLs for RSA were detected in the BC(4)F(3) population and only 13.3 % of the QTLs were detected at stage III. Most important QTLs for root traits were located on chromosome 6 near the locus umc1257 (bin 6.02-6.04) at stage I, and chromosome 10 near the locus umc2003 (bin 10.04) for number of AR across all three developmental stages. The regions of chromosome 7 near the locus bnlg339 (bin 7.03) and chromosome 1 near the locus bnlg1556 (bin 1.07) harbored QTLs for both GY- and LR-related traits at stages I and II, respectively. These results help to understand the genetic basis of root development under field conditions and their contribution to grain yield.
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Affiliation(s)
- Hongguang Cai
- Key Laboratory of Plant-Soil Interaction, MOE, College Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China
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335
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Smith RA, Findeis JL. Exploring audience segmentation: investigating adopter categories to diffuse an innovation to prevent famine in rural Mozambique. JOURNAL OF HEALTH COMMUNICATION 2012; 18:6-19. [PMID: 23020741 PMCID: PMC3772073 DOI: 10.1080/10810730.2012.688249] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Audience segmentation is a useful tool for designing effective campaigns. Further, the efficiency promised in diffusion science rests to some degree on the existence of adopter categories that can be identified and used to strategically disseminate prevention innovations. This study investigates the potential to identify adopter categories in potential recipients (n = 127) of an innovation to prevent food shortages in Mozambique. A 5-class model was found using latent class analysis, but it showed important differences from existing descriptions of adopter categories. Implications for theory and practice are discussed.
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Affiliation(s)
- Rachel A Smith
- Department of Communication Arts and Sciences and the Center for Infectious Disease Dynamics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
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336
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Santner J, Smolders E, Wenzel WW, Degryse F. First observation of diffusion-limited plant root phosphorus uptake from nutrient solution. PLANT, CELL & ENVIRONMENT 2012; 35:1558-1566. [PMID: 22452489 DOI: 10.1111/j.1365-3040.2012.02509.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Diffusion towards the root surface has recently been shown to control the uptake of metal ions from solutions. The uptake flux of phosphorus (P) from solutions often approaches the maximal diffusion flux at low external concentrations, suggesting diffusion-controlled uptake also for P. Potential diffusion limitation in P uptake from nutrient solutions was investigated by measuring P uptake of Brassica napus from solutions using P-loaded Al(2) O(3) nanoparticles as mobile P buffer. At constant, low free phosphate concentration, plant P uptake increased up to eightfold and that of passive, diffusion-based samplers up to 40-fold. This study represents the first experimental evidence of diffusion-limited P uptake by plant roots from nutrient solution. The Michaelis constant of the free phosphate ion obtained in unbuffered solutions (K(m) = 10.4 µmol L(-1) ) was 20-fold larger than in the buffered system (K(m) ∼0.5 µmol L(-1) ), indicating that K(m) s determined in unbuffered solutions do not represent the transporter affinity. Increases in the P uptake efficiency of plants by increasing the carrier affinity are therefore unlikely, while increased root surface area or exudation of P-solubilizing compounds are more likely to enhance P uptake. Furthermore, our results highlight the important role natural nanoparticles may have in plant P nutrition.
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Affiliation(s)
- Jakob Santner
- Rhizosphere Ecology and Biogeochemistry Group, Department of Forest and Soil Sciences, Institute of Soil Science, University of Natural Resources and Life Sciences Vienna, Konrad-Lorenz Strasse 24, 3430 Tulln, Austria.
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337
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Brown L, George T, Thompson J, Wright G, Lyon J, Dupuy L, Hubbard S, White P. What are the implications of variation in root hair length on tolerance to phosphorus deficiency in combination with water stress in barley (Hordeum vulgare)? ANNALS OF BOTANY 2012; 110:319-28. [PMID: 22539540 PMCID: PMC3394649 DOI: 10.1093/aob/mcs085] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Accepted: 03/05/2012] [Indexed: 05/17/2023]
Abstract
BACKGROUND AND AIMS Phosphorus commonly limits crop yield and is frequently applied as fertilizer; however, supplies of quality rock phosphate for fertilizer production are diminishing. Plants have evolved many mechanisms to increase their P-fertilizer use efficiency, and an understanding of these traits could result in improved long-term sustainability of agriculture. Here a mutant population is utilized to assess the impact of root hair length on P acquisition and yield under P-deficient conditions alone or when combined with drought. METHODS Mutants with various root hair phenotypes were grown in the glasshouse in pots filled with soil representing sufficient and deficient P treatments and, in one experiment, a range of water availability was also imposed. Plants were variously harvested at 7 d, 8 weeks and 14 weeks, and variables including root hair length, rhizosheath weight, biomass, P accumulation and yield were measured. KEY RESULTS The results confirmed the robustness of the root hair phenotypes in soils and their relationship to rhizosheath production. The data demonstrated that root hair length is important for shoot P accumulation and biomass, while only the presence of root hairs is critical for yield. Root hair presence was also critical for tolerance to extreme combined P deficit and drought stress, with genotypes with no root hairs suffering extreme growth retardation in comparison with those with root hairs. CONCLUSIONS The results suggest that although root hair length is not important for maintaining yield, the presence of root hairs is implicit to sustainable yield of barley under P-deficient conditions and when combined with extreme drought. Root hairs are a trait that should be maintained in future germplasm.
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Affiliation(s)
- L.K. Brown
- James Hutton Institute (JHI), Invergowrie, Dundee DD2 5DA, UK
| | - T.S. George
- James Hutton Institute (JHI), Invergowrie, Dundee DD2 5DA, UK
| | - J.A. Thompson
- James Hutton Institute (JHI), Invergowrie, Dundee DD2 5DA, UK
| | - G. Wright
- James Hutton Institute (JHI), Invergowrie, Dundee DD2 5DA, UK
| | - J. Lyon
- James Hutton Institute (JHI), Invergowrie, Dundee DD2 5DA, UK
| | - L. Dupuy
- James Hutton Institute (JHI), Invergowrie, Dundee DD2 5DA, UK
| | - S.F. Hubbard
- Division of Plant Science, University of Dundee at JHI, Invergowrie, Dundee DD2 5DA, UK
| | - P.J. White
- James Hutton Institute (JHI), Invergowrie, Dundee DD2 5DA, UK
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338
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Remans T, Thijs S, Truyens S, Weyens N, Schellingen K, Keunen E, Gielen H, Cuypers A, Vangronsveld J. Understanding the development of roots exposed to contaminants and the potential of plant-associated bacteria for optimization of growth. ANNALS OF BOTANY 2012; 110:239-52. [PMID: 22634257 PMCID: PMC3394651 DOI: 10.1093/aob/mcs105] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 03/28/2012] [Indexed: 05/24/2023]
Abstract
BACKGROUND AND SCOPE Plant responses to the toxic effects of soil contaminants, such as excess metals or organic substances, have been studied mainly at physiological, biochemical and molecular levels, but the influence on root system architecture has received little attention. Nevertheless, the precise position, morphology and extent of roots can influence contaminant uptake. Here, data are discussed that aim to increase the molecular and ecological understanding of the influence of contaminants on root system architecture. Furthermore, the potential of plant-associated bacteria to influence root growth by their growth-promoting and stress-relieving capacities is explored. METHODS Root growth parameters of Arabidopsis thaliana seedlings grown in vertical agar plates are quantified. Mutants are used in a reverse genetics approach to identify molecular components underlying quantitative changes in root architecture after exposure to excess cadmium, copper or zinc. Plant-associated bacteria are isolated from contaminated environments, genotypically and phenotypically characterized, and used to test plant root growth improvement in the presence of contaminants. KEY RESULTS The molecular determinants of primary root growth inhibition and effects on lateral root density by cadmium were identified. A vertical split-root system revealed local effects of cadmium and copper on root development. However, systemic effects of zinc exposure on root growth reduced both the avoidance of contaminated areas and colonization of non-contaminated areas. The potential for growth promotion and contaminant degradation of plant-associated bacteria was demonstrated by improved root growth of inoculated plants exposed to 2,4-di-nitro-toluene (DNT) or cadmium. CONCLUSIONS Knowledge concerning the specific influence of different contaminants on root system architecture and the molecular mechanisms by which this is achieved can be combined with the exploitation of plant-associated bacteria to influence root development and increase plant stress tolerance, which should lead to more optimal root systems for application in phytoremediation or safer biomass production.
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Affiliation(s)
- Tony Remans
- Environmental Biology, Hasselt University, Diepenbeek, Belgium.
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339
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Dupuy LX, Vignes M. An algorithm for the simulation of the growth of root systems on deformable domains. J Theor Biol 2012; 310:164-74. [PMID: 22732275 DOI: 10.1016/j.jtbi.2012.06.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Revised: 06/08/2012] [Accepted: 06/17/2012] [Indexed: 10/28/2022]
Abstract
Models of root systems are essential tools to understand how crops access and use soil resources during their development. However, scaling up such models to field scale remains a great challenge. In this paper, we detail a new approach to compute the growth of root systems based on density distribution functions. Growth was modelled as the dynamics of root apical meristems, using Partial Differential Equations. Trajectories of root apical meristems were used to deform root domains, the bounded support of root density functions, and update density distributions at each time increment of the simulation. Our results demonstrate that it is possible to predict the growth of root domains, by including developmentally meaningful parameters such as root elongation rate, gravitropic rate and branching rate. Models of this type are computationally more efficient than state-of-the-art finite volume methods. At a given prediction accuracy, computational time is over 10 times quicker; it allowed deformable models to be used to simulate ensembles of interacting plants. Application to root competition in crop-weed systems is demonstrated. The models presented in this study indicate that similar approaches could be developed to model shoot or whole plant processes with potential applications in crop and ecological modelling.
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340
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Kell DB. Large-scale sequestration of atmospheric carbon via plant roots in natural and agricultural ecosystems: why and how. Philos Trans R Soc Lond B Biol Sci 2012; 367:1589-97. [PMID: 22527402 PMCID: PMC3321694 DOI: 10.1098/rstb.2011.0244] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The soil holds twice as much carbon as does the atmosphere, and most soil carbon is derived from recent photosynthesis that takes carbon into root structures and further into below-ground storage via exudates therefrom. Nonetheless, many natural and most agricultural crops have roots that extend only to about 1 m below ground. What determines the lifetime of below-ground C in various forms is not well understood, and understanding these processes is therefore key to optimising them for enhanced C sequestration. Most soils (and especially subsoils) are very far from being saturated with organic carbon, and calculations show that the amounts of C that might further be sequestered (http://dbkgroup.org/carbonsequestration/rootsystem.html) are actually very great. Breeding crops with desirable below-ground C sequestration traits, and exploiting attendant agronomic practices optimised for individual species in their relevant environments, are therefore important goals. These bring additional benefits related to improvements in soil structure and in the usage of other nutrients and water.
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Affiliation(s)
- Douglas B Kell
- School of Chemistry and Manchester Interdisciplinary Biocentre, University of Manchester, 131 Princess St, Manchester M1 7DN, UK.
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341
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Pacheco-Villalobos D, Hardtke CS. Natural genetic variation of root system architecture from Arabidopsis to Brachypodium: towards adaptive value. Philos Trans R Soc Lond B Biol Sci 2012; 367:1552-8. [PMID: 22527398 PMCID: PMC3321687 DOI: 10.1098/rstb.2011.0237] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Root system architecture is a trait that displays considerable plasticity because of its sensitivity to environmental stimuli. Nevertheless, to a significant degree it is genetically constrained as suggested by surveys of its natural genetic variation. A few regulators of root system architecture have been isolated as quantitative trait loci through the natural variation approach in the dicotyledon model, Arabidopsis. This provides proof of principle that allelic variation for root system architecture traits exists, is genetically tractable, and might be exploited for crop breeding. Beyond Arabidopsis, Brachypodium could serve as both a credible and experimentally accessible model for root system architecture variation in monocotyledons, as suggested by first glimpses of the different root morphologies of Brachypodium accessions. Whether a direct knowledge transfer gained from molecular model system studies will work in practice remains unclear however, because of a lack of comprehensive understanding of root system physiology in the native context. For instance, apart from a few notable exceptions, the adaptive value of genetic variation in root system modulators is unknown. Future studies should thus aim at comprehensive characterization of the role of genetic players in root system architecture variation by taking into account the native environmental conditions, in particular soil characteristics.
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Affiliation(s)
| | - Christian S. Hardtke
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, 1015 Lausanne, Switzerland
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342
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Lynch JP, Brown KM. New roots for agriculture: exploiting the root phenome. Philos Trans R Soc Lond B Biol Sci 2012; 367:1598-604. [PMID: 22527403 PMCID: PMC3321693 DOI: 10.1098/rstb.2011.0243] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Recent advances in root biology are making it possible to genetically design root systems with enhanced soil exploration and resource capture. These cultivars would have substantial value for improving food security in developing nations, where yields are limited by drought and low soil fertility, and would enhance the sustainability of intensive agriculture. Many of the phenes controlling soil resource capture are related to root architecture. We propose that a better understanding of the root phenome is needed to effectively translate genetic advances into improved crop cultivars. Elementary, unique root phenes need to be identified. We need to understand the 'fitness landscape' for these phenes: how they affect crop performance in an array of environments and phenotypes. Finally, we need to develop methods to measure phene expression rapidly and economically without artefacts. These challenges, especially mapping the fitness landscape, are non-trivial, and may warrant new research and training modalities.
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Affiliation(s)
- Jonathan P Lynch
- Department of Horticulture, Pennsylvania State University, University Park, PA 16802, USA.
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343
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Ingram PA, Zhu J, Shariff A, Davis IW, Benfey PN, Elich T. High-throughput imaging and analysis of root system architecture in Brachypodium distachyon under differential nutrient availability. Philos Trans R Soc Lond B Biol Sci 2012; 367:1559-69. [PMID: 22527399 PMCID: PMC3321691 DOI: 10.1098/rstb.2011.0241] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Nitrogen (N) and phosphorus (P) deficiency are primary constraints for plant productivity, and root system architecture (RSA) plays a vital role in the acquisition of these nutrients. The genetic determinants of RSA are poorly understood, primarily owing to the complexity of crop genomes and the lack of sufficient RSA phenotyping methods. The objective of this study was to characterize the RSA of two Brachypodium distachyon accessions under different nutrient availability. To do so, we used a high-throughput plant growth and imaging platform, and developed software that quantified 19 different RSA traits. We found significant differences in RSA between two Brachypodium accessions grown on nutrient-rich, low-N and low-P conditions. More specifically, one accession maintained axile root growth under low N, while the other accession maintained lateral root growth under low P. These traits resemble the RSA of crops adapted to low-N and -P conditions, respectively. Furthermore, we found that a number of these traits were highly heritable. This work lays the foundation for future identification of important genetic components of RSA traits under nutrient limitation using a mapping population derived from these two accessions.
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Affiliation(s)
| | | | | | | | - Philip N. Benfey
- GrassRoots Biotechnology, Durham, NC, USA
- Department of Biology and Center for Systems Biology, Duke University, Durham, NC, USA
| | - Tedd Elich
- GrassRoots Biotechnology, Durham, NC, USA
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344
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Gan Y, Bernreiter A, Filleur S, Abram B, Forde BG. Overexpressing the ANR1 MADS-box gene in transgenic plants provides new insights into its role in the nitrate regulation of root development. PLANT & CELL PHYSIOLOGY 2012; 53:1003-16. [PMID: 22523192 DOI: 10.1093/pcp/pcs050] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The expression of the ANR1 MADS-box gene was manipulated in transgenic plants to investigate its role in the NO(3)(-)-dependent regulation of root development in Arabidopsis thaliana. Constitutive overexpression of ANR1 in roots, achieved using GAL4 enhancer trap lines, resulted in more rapid early seedling development, increased lengths and numbers of lateral roots and increased shoot fresh weight. Based on results obtained with five different enhancer trap lines, the overexpression of ANR1 in the lateral root tips appears to be more important for this phenotype than its level of expression in the developing lateral root primordia. Dexamethasone-mediated induction of ANR1 in lines expressing an ANR1-GR (glucocorticoid receptor) fusion protein stimulated lateral root growth but not primary root growth. Short-term (24 h) dexamethasone treatments led to prolonged stimulation of lateral root growth, whether the lateral roots were already mature or still unemerged at the time of treatment. In split-root experiments, localized application of dexamethasone to half of the root system of an ANR1-GR line elicited a localized increase in both the length and numbers of lateral roots, mimicking the effect of a localized NO(3)(-) treatment. In both types of transgenic line, the root phenotype was strongly dependent on the presence of NO(3)(-), indicating that there are additional components involved in ANR1 function that are NO(3)(-) regulated. The implications of these results for our understanding of ANR1's mode of action in the root response to localized NO(3)(-) are discussed.
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Affiliation(s)
- Yinbo Gan
- Centre for Sustainable Agriculture, Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
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345
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Gowda VRP, Henry A, Vadez V, Shashidhar HE, Serraj R. Water uptake dynamics under progressive drought stress in diverse accessions of the OryzaSNP panel of rice (Oryza sativa). FUNCTIONAL PLANT BIOLOGY : FPB 2012; 39:402-411. [PMID: 32480792 DOI: 10.1071/fp12015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 03/16/2012] [Indexed: 06/11/2023]
Abstract
In addition to characterising root architecture, evaluating root water uptake ability is important for understanding drought response. A series of three lysimeter studies were conducted using the OryzaSNP panel, which consists of 20 diverse rice (Oryza sativa L.) genotypes. Large genotypic differences in drought response were observed in this genotype panel in terms of plant growth and water uptake. Total water uptake and daily water uptake rates in the drought-stress treatment were correlated with root length density, especially at depths below 30cm. Patterns of water uptake among genotypes remained consistent throughout the stress treatments: genotypes that initially extracted more water were the same genotypes that extracted more water at the end of the study. These results suggest that response to drought by deep root growth, rather than a conservative soil water pattern, seems to be important for lowland rice. Genotypes in the O. sativa type aus group showed some of the greatest water uptake and root growth values. Since the OryzaSNP panel has been genotyped in detail with SNP markers, we expect that these results will be useful for understanding the genetics of rice root growth and function for water uptake in response to drought.
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Affiliation(s)
- Veeresh R P Gowda
- International Rice Research Institute, DAPO Box 7777, Metro Manila 1301, Philippines
| | - Amelia Henry
- International Rice Research Institute, DAPO Box 7777, Metro Manila 1301, Philippines
| | - Vincent Vadez
- International Crops Research Institute for the Semiarid Tropics, Patancheru, Hyderabad, Andra Pradesh, India
| | - H E Shashidhar
- Department of Biotechnology, College of Agriculture, University of Agricultural Sciences, GKVK, Bangalore 560065, India
| | - Rachid Serraj
- International Rice Research Institute, DAPO Box 7777, Metro Manila 1301, Philippines
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346
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Chochois V, Vogel JP, Watt M. Application of Brachypodium to the genetic improvement of wheat roots. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:3467-3474. [PMID: 22467408 DOI: 10.1093/jxb/ers044] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
To meet the demands of a larger and more affluent global population, wheat yields must increase faster this century than last, with less irrigation, fertilizer, and land. Modelling and experiments consistently demonstrate a large potential for increasing wheat productivity by improving root systems; however, application of research to new varieties is slow because of the inherent difficulties associated with working underground. This review makes the case for the use of the model grass Brachypodium distachyon to simplify root research and accelerate the identification of genes underlying wheat root improvement. Brachypodium is a small temperate grass with many genomic, genetic, and experimental resources that make it a tractable model plant. Brachypodium and wheat have very similar root anatomies which are distinct from rice root anatomy that is specialized to help it overcome anaerobic conditions associated with submerged roots. As a dicotyledonous plant, Arabidopsis has an even more divergent root system that features a tap root system and cambia with secondary growth, both of which are lacking in the grasses. The major advantage of Brachypodium is its small stature that allows the adult grass root system to be readily phenotyped, unlike rice and maize. This will facilitate the identification of genes in adult roots that greatly influence yield by modulating water uptake during flowering and grain development. A summary of the advantages of Brachypodium for root studies is presented, including the adult root system architecture and root growth during grain development. Routes to translate discoveries from Brachypodium to wheat are also discussed.
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347
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Fita A, Bowen HC, Hayden RM, Nuez F, Picó B, Hammond JP. Diversity in expression of phosphorus (P) responsive genes in Cucumis melo L. PLoS One 2012; 7:e35387. [PMID: 22536378 PMCID: PMC3334927 DOI: 10.1371/journal.pone.0035387] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 03/15/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Phosphorus (P) is a major limiting nutrient for plant growth in many soils. Studies in model species have identified genes involved in plant adaptations to low soil P availability. However, little information is available on the genetic bases of these adaptations in vegetable crops. In this respect, sequence data for melon now makes it possible to identify melon orthologues of candidate P responsive genes, and the expression of these genes can be used to explain the diversity in the root system adaptation to low P availability, recently observed in this species. METHODOLOGY AND FINDINGS Transcriptional responses to P starvation were studied in nine diverse melon accessions by comparing the expression of eight candidate genes (Cm-PAP10.1, Cm-PAP10.2, Cm-RNS1, Cm-PPCK1, Cm-transferase, Cm-SQD1, Cm-DGD1 and Cm-SPX2) under P replete and P starved conditions. Differences among melon accessions were observed in response to P starvation, including differences in plant morphology, P uptake, P use efficiency (PUE) and gene expression. All studied genes were up regulated under P starvation conditions. Differences in the expression of genes involved in P mobilization and remobilization (Cm-PAP10.1, Cm-PAP10.2 and Cm-RNS1) under P starvation conditions explained part of the differences in P uptake and PUE among melon accessions. The levels of expression of the other studied genes were diverse among melon accessions, but contributed less to the phenotypical response of the accessions. CONCLUSIONS This is the first time that these genes have been described in the context of P starvation responses in melon. There exists significant diversity in gene expression levels and P use efficiency among melon accessions as well as significant correlations between gene expression levels and phenotypical measurements.
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Affiliation(s)
- Ana Fita
- Centro de Conservación y Mejora de la Agrodiversidad Valenciana, Universitat Politècnica de València, Valencia, Spain.
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348
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Bouteillé M, Rolland G, Balsera C, Loudet O, Muller B. Disentangling the intertwined genetic bases of root and shoot growth in Arabidopsis. PLoS One 2012; 7:e32319. [PMID: 22384215 PMCID: PMC3286473 DOI: 10.1371/journal.pone.0032319] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Accepted: 01/25/2012] [Indexed: 01/11/2023] Open
Abstract
Root growth and architecture are major components of plant nutrient and water use efficiencies and these traits are the matter of extensive genetic analysis in several crop species. Because root growth relies on exported assimilate from the shoot, and changes in assimilate supply are known to alter root architecture, we hypothesized (i) that the genetic bases of root growth could be intertwined with the genetic bases of shoot growth and (ii) that the link could be either positive, with alleles favouring shoot growth also favouring root growth, or negative, because of competition for assimilates. We tested these hypotheses using a quantitative genetics approach in the model species Arabidopsis thaliana and the Bay-0 × Shahdara recombinant inbred lines population. In accordance with our hypothesis, root and shoot growth traits were strongly correlated and most root growth quantitative trait loci (QTLs) colocalized with shoot growth QTLs with positive alleles originating from either the same or the opposite parent. In order to identify regions that could be responsible for root growth independently of the shoot, we generated new variables either based on root to shoot ratios, residuals of root to shoot correlations or coordinates of principal component analysis. These variables showed high heritability allowing genetic analysis. They essentially all yielded similar results pointing towards two regions involved in the root--shoot balance. Using Heterogeneous Inbred Families (a kind of near-isogenic lines), we validated part of the QTLs present in these two regions for different traits. Our study thus highlights the difficulty of disentangling intertwined genetic bases of root and shoot growth and shows that this difficulty can be overcome by using simple statistical tools.
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Affiliation(s)
- Marie Bouteillé
- INRA, Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux, UMR759, INRA, Montpellier, France
- SupAgro, Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux, UMR759, INRA, Montpellier, France
| | - Gaëlle Rolland
- INRA, Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux, UMR759, INRA, Montpellier, France
- SupAgro, Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux, UMR759, INRA, Montpellier, France
| | - Crispulo Balsera
- INRA, Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux, UMR759, INRA, Montpellier, France
- SupAgro, Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux, UMR759, INRA, Montpellier, France
| | - Olivier Loudet
- INRA, UMR1318, Institut Jean-Pierre Bourgin, Versailles, France
- AgroParisTech, UMR1318, Institut Jean-Pierre Bourgin, Versailles, France
| | - Bertrand Muller
- INRA, Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux, UMR759, INRA, Montpellier, France
- SupAgro, Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux, UMR759, INRA, Montpellier, France
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349
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Kijoji AA, Nchimbi-Msolla S, Kanyeka ZL, Klassen SP, Serraj R, Henry A. Water extraction and root traits in Oryza sativa × Oryza glaberrima introgression lines under different soil moisture regimes. FUNCTIONAL PLANT BIOLOGY : FPB 2012; 40:54-66. [PMID: 32481086 DOI: 10.1071/fp12163] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Accepted: 09/21/2012] [Indexed: 06/11/2023]
Abstract
Drought is a major constraint to rainfed rice production in some parts of sub Saharan Africa (SSA) because of irregular and low rainfall. Improving root water uptake during progressive soil drying could contribute to terminal drought stress resistance. Two lysimeter experiments were conducted using 200 introgression lines (ILs) derived from Oryza sativa L.×Oryza glaberrima Steud. crosses (IR64/RAM54 and IR64/RAM90) to characterise water uptake and root traits under progressive soil drying and to assess genetic differences among these lines in relation to drought stress. The lysimeter facility setup and protocols for simultaneous monitoring of water uptake rates and leaf area are described. Significant genetic variability for water uptake and root traits among the ILs was observed under drought stress. Water uptake in the drought stress treatments was correlated with root length density (RLD) and root dry matter (RDM) at lower soil depths. The highest RLD values at depth were observed among the RAM90 ILs and genetic differences were observed between RAM90 and RAM54 populations, implying that accession RAM90 could be used as a source for improving drought avoidance in lowland rice. The ILs with greater water uptake identified in this study will be used in future research for improving drought resistance of rice in SSA.
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Affiliation(s)
- Abubakary A Kijoji
- Sokoine University of Agriculture, Department of Crop Science and Production, PO Box 3005, Morogoro, Tanzania
| | - Susan Nchimbi-Msolla
- Sokoine University of Agriculture, Department of Crop Science and Production, PO Box 3005, Morogoro, Tanzania
| | - Zakaria L Kanyeka
- International Rice Research Institute, Southern and East Africa Regional Office, Box 33581, Dar es Salaam, Tanzania
| | - Stephen P Klassen
- International Rice Research Institute, Crop and Environmental Sciences Division, DAPO Box 7777, Metro Manila, Philippines
| | - Rachid Serraj
- International Rice Research Institute, Crop and Environmental Sciences Division, DAPO Box 7777, Metro Manila, Philippines
| | - Amelia Henry
- International Rice Research Institute, Crop and Environmental Sciences Division, DAPO Box 7777, Metro Manila, Philippines
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350
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Edelstein DM, Tonjes DJ. Modeling an Improvement in Phosphorus Utilization in Tropical Agriculture. ACTA ACUST UNITED AC 2012. [DOI: 10.1080/10440046.2011.627993] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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