Application of biochemical studies to improving nitrogen fixation

Vance, Carroll P.; Lamb, J. F. S.

doi:10.1071/ea00007

Cited by 9 publications

(3 citation statements)

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“…Selection for increased root hair abundance has led to enhanced P acquisition in bean, clover, barley and Arabidopsis . Wissuwa & Ae (2001) have identified four quantitative trait loci (QTL) in rice ( Oryza sativa ) associated with increased P uptake under P‐deficiency, two of which were related to maintenance of root growth under low P. Similarly, these root architecture traits are also important in the acquisition of N and other nutrients (Klepper, 1992; Zhang & Forde, 1998; Lamb et al ., 2000; Vance & Lamb, 2001).…”

Section: Improving P Acquisitionmentioning

confidence: 99%

Phosphorus acquisition and use: critical adaptations by plants for securing a nonrenewable resource

2003

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Contents Introduction 424 The phosphorus conundrum 424 Adaptations to low P 424 Uptake of P 424 P deficiency alters root development and function 426 P deficiency modifies carbon metabolism 431 Acid phosphatase 436 Genetic regulation of P responsive genes 437 Improving P acquisition 439 Synopsis 440 Summary Phosphorus (P) is limiting for crop yield on > 30% of the world's arable land and, by some estimates, world resources of inexpensive P may be depleted by 2050. Improvement of P acquisition and use by plants is critical for economic, humanitarian and environmental reasons. Plants have evolved a diverse array of strategies to obtain adequate P under limiting conditions, including modifications to root architecture, carbon metabolism and membrane structure, exudation of low molecular weight organic acids, protons and enzymes, and enhanced expression of the numerous genes involved in low‐P adaptation. These adaptations may be less pronounced in mycorrhizal‐associated plants. The formation of cluster roots under P‐stress by the nonmycorrhizal species white lupin (Lupinus albus), and the accompanying biochemical changes exemplify many of the plant adaptations that enhance P acquisition and use. Physiological, biochemical, and molecular studies of white lupin and other species response to P‐deficiency have identified targets that may be useful for plant improvement. Genomic approaches involving identification of expressed sequence tags (ESTs) found under low‐P stress may also yield target sites for plant improvement. Interdisciplinary studies uniting plant breeding, biochemistry, soil science, and genetics under the large umbrella of genomics are prerequisite for rapid progress in improving nutrient acquisition and use in plants.

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Section: Improving P Acquisitionmentioning

confidence: 99%

Phosphorus acquisition and use: critical adaptations by plants for securing a nonrenewable resource

2003

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“…Based on immunoprecipitation with specific antibodies, about 50 % of alfalfa nodule MDH activity can be attributed to neMDH activity. Immunolocalization indicates that neMDH can be predominantly found in infected cells while cytosolic MDH (cMDH) seems to be the most abundant form in uninfected cells (Vance and Lamb, 2001). Comparable nodule enhanced forms of MDH have been found in pea and soybean (Fedorova et al, 1999).…”

Section: Nitrogen Feedback-regulationmentioning

confidence: 99%

“…The advent of techniques allowing specific targeting of single enzymes in legume nodules does not only contribute to our understanding of nitrogen fixation regulation, but holds the potential for improving the performance of symbiotically grown legumes beyond results achievable by conventional breeding (Vance and Lamb, 2001). However, a more precise understanding of factors limiting and regulating nitrogen fixation seems to be important for increasing legume productivity via improved nitrogen fixation.…”

Section: Introductionmentioning

confidence: 99%

How are nitrogen fixation rates regulated in legumes?

Schulze¹

2004

Z. Pflanzenernähr. Bodenk.

137

101

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± ZusammenfassungSymbiotic nitrogen fixation by the legume-Rhizobium symbiosis is a finely regulated process that involves significant carbon and energy metabolism by the plant. At present, there are three competing theories as to how the regulation of the process is achieved at the whole plant level. Theory one (carbon supply regulation) states that nitrogen fixation rates are regulated by either current nodule assimilate supply or through metabolism of assimilates into compounds that can be used by the bacteroids. A second theory (oxygen supply regulation) assumes that oxygen diffusion into the nodules is tightly regulated and is the principal regulatory factor for nitrogen fixation rates. A third theory (N-feedback regulation) suggests that a product of nitrogen fixation or assimilation exerts a feedback regulatory impact. The paper summarizes experimental data which support or reject the mentioned theories. Moreover, implications of nitrogen fixation under P stress and of phenomena connected with the argon or acetylene induced decline in nitrogenase activity for the understanding of nitrogen fixation regulation are discussed. It is concluded that we currently have no theory that explains all aspects and experimental results concerning the regulation of nitrogen fixation in legumes. With our growing ability to impact the process, e.g., by genetic engineering, this understanding of nitrogen fixation regulation has potential to be translated into agronomically sustainable benefits. Wie werden die Stickstofffixierungsraten bei Leguminosen reguliert?Die symbiontische N 2 -Fixierung bei Leguminosen ist ein fein regulierter Prozess, der einen massiven Substanzumsatz in der Pflanze beinhaltet. Gegenwärtig gibt es drei konkurrierende Theorien über die Art, wie die Regulation des Prozesses auf Ganzpflanzenbasis erreicht wird. Eine Theorie (Regulation über die Kohlenstoffversorgung) geht von einer Abhängigkeit bzw. Regulation der N 2 -Fixierungsraten entweder durch die Assimilatversorgung der Knöllchen oder von einer Limitierung des nötigen metabolischen Umsatzes der Assimilate in für den Bakteroiden verwertbare Verbindungen aus. In der zweiten Theorie (Regulation über die Sauerstoffversorgung) wird angenommen, dass die Sauerstoffdiffusion in das Knöllchen einer strengen Regulation unterliegt und dies der prinzipielle Regulationsfaktor für die N 2 -Fixierungsraten ist. Die dritte Theorie (ªN-feedbackº-Regulation) besagt, dass ein bisher nicht zweifelsfrei identifiziertes Produkt der Stickstoffixierung oder -assimilation eine ªfeedbackª-Wirkung auf die N 2 -Fixierung ausübt. Der vorliegende Artikel fasst die bis heute gesammelten experimentellen Daten zusammen, die für oder gegen die genannten Theorien sprechen. In diesem Zusammenhang wird diskutiert, auf welche Weise die Regulation der N 2 -Fixierung unter P-Mangelbedingungen erfolgt. Schlieûlich wird diskutiert, ob die Klärung der Ursache der Azetylen-bzw. Argon-induzierten Abnahme der Nitrogenaseaktivität zum Verständnis der Regulation der N 2 -Fixierung beitragen kan...

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Carbon And Nitrogen Metabolism In Actinorhizal Nodules

Valverde

Huss‐Danell

Nitrogen-Fixing Actinorhizal Symbioses

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Application of biochemical studies to improving nitrogen fixation

Cited by 9 publications

References 72 publications

Phosphorus acquisition and use: critical adaptations by plants for securing a nonrenewable resource

Phosphorus acquisition and use: critical adaptations by plants for securing a nonrenewable resource

How are nitrogen fixation rates regulated in legumes?

Carbon And Nitrogen Metabolism In Actinorhizal Nodules

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