title: Physiological and molecular alterations in plants exposed to high [CO2] under phosphorus stress.
abstract: Atmospheric [CO2] has increased substantially in recent decades and will continue to do so, whereas the availability of phosphorus (P) is limited and unlikely to increase in the future. P is a non-renewable resource, and it is essential to every form of life. P is a key plant nutrient controlling the responsiveness of photosynthesis to [CO2]. Increases in [CO2] typically results in increased biomass through stimulation of net photosynthesis, and hence enhance the demand for P uptake. However, most soils contain low concentrations of available P. Therefore, low P is one of the major growth-limiting factors for plants in many agricultural and natural ecosystems. The adaptive responses of plants to [CO2] and P availability encompass alterations at morphological, physiological, biochemical and molecular levels. In general low P reduces growth, whereas high [CO2] enhances it particularly in C3 plants. Photosynthetic capacity is often enhanced under high [CO2] with sufficient P supply through modulation of enzyme activities involved in carbon fixation such as ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). However, high [CO2] with low P availability results in enhanced dry matter partitioning towards roots. Alterations in below-ground processes including root morphology, exudation and mycorrhizal association are influenced by [CO2] and P availability. Under high P availability, elevated [CO2] improves the uptake of P from soil. In contrast, under low P availability, high [CO2] mainly improves the efficiency with which plants produce biomass per unit P. At molecular level, the spatio-temporal regulation of genes involved in plant adaptation to low P and high [CO2] has been studied individually in various plant species. Genome-wide expression profiling of high [CO2] grown plants revealed hormonal regulation of biomass accumulation through complex transcriptional networks. Similarly, differential transcriptional regulatory networks are involved in P-limitation responses in plants. Analysis of expression patterns of some typical P-limitation induced genes under high [CO2] suggests that long-term exposure of plants to high [CO2] would have a tendency to stimulate similar transcriptional responses as observed under P-limitation. However, studies on the combined effect of high [CO2] and low P on gene expression are scarce. Such studies would provide insights into the development of P efficient crops in the context of anticipated increases in atmospheric [CO2].
authors: Division of Plant Physiology, Indian Agricultural Research Institute, New Delhi 110012, India. Electronic address: renu.pandey.iari@gmail.com.
authors: Renu
authors: R
authors: Pandey
authors: Department of Biology, University of Antwerp, 2610, Belgium.
authors: Gaurav
authors: G
authors: Zinta
authors: Department of Biology, University of Antwerp, 2610, Belgium; Department of Botany, Faculty of Science, University of Beni-Sueif, Beni-Sueif 62511, Egypt.
authors: Hamada
authors: H
authors: AbdElgawad
authors: Department of Botany, Aligarh Muslim University, Aligarh 201002, India.
authors: Altaf
authors: A
authors: Ahmad
authors: Division of Plant Physiology, Indian Agricultural Research Institute, New Delhi 110012, India.
authors: Vanita
authors: V
authors: Jain
authors: Department of Biology, University of Antwerp, 2610, Belgium.
authors: Ivan A
authors: IA
authors: Janssens
mesh_terms: D002245:Carbon Dioxide / Q000378:metabolism*; D017753:Ecosystem; D018506:Gene Expression Regulation, Plant; D053263:Gene Regulatory Networks; D010758:Phosphorus / Q000378:metabolism*; D010788:Photosynthesis / Q000235:genetics; D063245:Plant Development / Q000235:genetics*; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D010944:Plants / Q000235:genetics* / Q000378:metabolism; D012273:Ribulose-Bisphosphate Carboxylase / Q000096:biosynthesis / Q000235:genetics; D012987:Soil; D013312:Stress, Physiological
chemical_list: D012987:Soil; D002245:Carbon Dioxide; D010758:Phosphorus; D012273:Ribulose-Bisphosphate Carboxylase
keywords: Elevated CO(2); Growth; Mycorrhiza; Phosphorus limitation; Photosynthesis; Root exudation; Root morphology; Transcriptional regulation