Agriculture Reference
In-Depth Information
Chapter 4
Efficient Mineral Nutrition: Genetic
Improvement of Phosphate Uptake and Use
Efficiency in Crops
Astrid Gruen, Martin R. Broadley, Peter Buchner,
and Malcolm J. Hawkesford
Abstract Phosphorus (P) is an essential macronutrient for plants, the lack of which
can be a major constraint for agricultural productivity. Economic, political and
environmental factors have prioritized the need for research on P acquisition
efficiency (PAE), P utilization efficiency (PUE) and P fertiliser uptake efficiency
in crops. P has critical functions in plants and complex interactions in soils.
Appropriate screening approaches and implications of improvement in crop pro-
duction are discussed. P acquisition is mediated by members of phosphate trans-
porter families and the roles of these phosphate transporters as well as enzymes
involved in P partitioning and re-translocation are complex. There is also a critical
importance of regulatory genes including transcription factors, signalling pathways
and apparently other P-responsive genes with unknown function. Furthermore,
morphological and biochemical responses enhance P solubility in the soil and
facilitate uptake and include root plasticity, secretion processes and symbioses.
Exploitation of genetic variation, classical breeding and biotechnological gene
modification of target genes are future routes for crop improvement. There is a
need for selection not just for uptake but also focussing on P storage pools within
cells and tissues, and additionally a consideration of crop P requirements during the
different growth stages of crops. The review concludes with a summary giving an
outlook to future questions related to crop PAE/PUE improvement.
Keywords Phosphorus • Acquisition efficiency • Utilization efficiency • Phosphate
transporters • Mycorrhiza • Signaling • Diversity • Adaptation • QTL
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