Responses of root architecture development to low phosphorus availability: a review

Abstract

BackgroundPhosphorus (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.ScopeThis 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.ConclusionsThe 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.

Ecological relevance of strigolactones in nutrient uptake and other abiotic stresses, and in plant-microbe interactions below-ground

“…Here, it was shown to stimulate lateral root and root hair formation, as well as their subsequent development, and to inhibit primary root growth (Fig. 2) (reviewed by Niu et al 2013). In maize and rice, P starvation inhibits lateral root formation, while it promotes primary root growth (Li et al 2012;Sun et al 2014).…”

Duplicate and Conquer: Multiple Homologs ofPHOSPHORUS-STARVATION TOLERANCE1Enhance Phosphorus Acquisition and Sorghum Performance on Low-Phosphorus Soils

“…Another strategy to cope with low-P availability is to increase the soil volume accessed by root systems by forming mycorrhizal symbioses Smith and Smith, 2012;Rai et al, 2013). Due to low-P mobility on tropical soils, changes in root architecture and morphology enhance P uptake by facilitating soil exploration (Williamson et al, 2001;Ho et al, 2005;Walk et al, 2006;Svistoonoff et al, 2007;Lynch, 2011;Ingram et al, 2012;Niu et al, 2013). Root structural changes leading to higher P uptake include increased root hair growth (Yan et al, 2004;Haling et al, 2013;Lan et al, 2013) and length and enhancing lateral root over primary root growth (Williamson et al, 2001;Wang et al, 2013).…”

Growth and nutrient efficiency of Betula alnoides clones in response to phosphorus supply

“…Clone BY1 performed the best with the maximum biomass, root to shoot ratio and internal nutrient supply. Further research on physiological plasticity, such as leaf traits, organic acid and mycorrhizal responses of B. alnoides clones to phosphorus supply should be undertaken to better understand the adaptive mechanisms of plants to low phosphorus contents of growing media or soils (Plassard & Dell 2010, Niu et al 2013, Richardson et al 2011, Xie et al 2014, Zhao et al 2013). …”