Opportunities for improving phosphorus‐use efficiency in crop plants

<jats:title>Summary</jats:title><jats:p>Limitation of grain crop productivity by phosphorus (P) is widespread and will probably increase in the future. Enhanced P efficiency can be achieved by improved uptake of phosphate from soil (P‐acquisition efficiency) and by improved productivity per unit P taken up (P‐use efficiency). This review focuses on improved P‐use efficiency, which can be achieved by plants that have overall lower P concentrations, and by optimal distribution and redistribution of P in the plant allowing maximum growth and biomass allocation to harvestable plant parts. Significant decreases in plant P pools may be possible, for example, through reductions of superfluous ribosomal RNA and replacement of phospholipids by sulfolipids and galactolipids. Improvements in P distribution within the plant may be possible by increased remobilization from tissues that no longer need it (e.g. senescing leaves) and reduced partitioning of P to developing grains. Such changes would prolong and enhance the productive use of P in photosynthesis and have nutritional and environmental benefits. Research considering physiological, metabolic, molecular biological, genetic and phylogenetic aspects of P‐use efficiency is urgently needed to allow significant progress to be made in our understanding of this complex trait.</jats:p><jats:p><jats:table-wrap position="anchor"> <jats:table frame="void"> <jats:col /> <jats:col /> <jats:col /> <jats:thead> <jats:tr> <jats:th /> <jats:th>Contents</jats:th> <jats:th /> </jats:tr> </jats:thead> <jats:tbody> <jats:tr> <jats:td /> <jats:td>Summary</jats:td> <jats:td>306</jats:td> </jats:tr> <jats:tr> <jats:td>I.</jats:td> <jats:td><jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#ss1">The need to use phosphorus efficiently</jats:ext-link></jats:td> <jats:td>307</jats:td> </jats:tr> <jats:tr> <jats:td>II.</jats:td> <jats:td><jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#ss2">P‐use efficiency and P dynamics in a growing crop</jats:ext-link></jats:td> <jats:td>307</jats:td> </jats:tr> <jats:tr> <jats:td>III.</jats:td> <jats:td><jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#ss3">P pools in plants</jats:ext-link></jats:td> <jats:td>307</jats:td> </jats:tr> <jats:tr> <jats:td>IV.</jats:td> <jats:td><jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#ss6">Phosphorus pools and growth rates</jats:ext-link></jats:td> <jats:td>310</jats:td> </jats:tr> <jats:tr> <jats:td>V.</jats:td> <jats:td><jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#ss7">Are crops different from other plants in their P concentration?</jats:ext-link></jats:td> <jats:td>310</jats:td> </jats:tr> <jats:tr> <jats:td>VI.</jats:td> <jats:td><jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#ss8">Phosphorus use and photosynthesis</jats:ext-link></jats:td> <jats:td>311</jats:td> </jats:tr> <jats:tr> <jats:td>VII.</jats:td> <jats:td><jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#ss9">Crop development and canopy P distribution</jats:ext-link></jats:td> <jats:td>312</jats:td> </jats:tr> <jats:tr> <jats:td>VIII.</jats:td> <jats:td><jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#ss10">Internal redistribution of P in a growing vegetative plant</jats:ext-link></jats:td> <jats:td>313</jats:td> </jats:tr> <jats:tr> <jats:td>IX.</jats:td> <jats:td><jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#ss11">Allocation of P to reproductive structures</jats:ext-link></jats:td> <jats:td>314</jats:td> </jats:tr> <jats:tr> <jats:td>X.</jats:td> <jats:td><jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#ss12">Constraints to P remobilisation</jats:ext-link></jats:td> <jats:td>315</jats:td> </jats:tr> <jats:tr> <jats:td>XI.</jats:td> <jats:td><jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#ss13">Do physiological or phylogenetic trade‐offs constrain traits that could improve PUE?</jats:ext-link></jats:td> <jats:td>316</jats:td> </jats:tr> <jats:tr> <jats:td>XII.</jats:td> <jats:td><jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#ss14">Identifying genetic loci associated with PUE</jats:ext-link></jats:td> <jats:td>316</jats:td> </jats:tr> <jats:tr> <jats:td>XIII.</jats:td> <jats:td><jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#ss15">Conclusions</jats:ext-link></jats:td> <jats:td>317</jats:td> </jats:tr> <jats:tr> <jats:td /> <jats:td><jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#ss16">Acknowledgements</jats:ext-link></jats:td> <jats:td>317</jats:td> </jats:tr> <jats:tr> <jats:td /> <jats:td><jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#ss17">References</jats:ext-link></jats:td> <jats:td>317</jats:td> </jats:tr> </jats:tbody> </jats:table> </jats:table-wrap></jats:p>