Molecular mechanisms underpinning phosphorus‐use efficiency in rice

Abstract

Orthophosphate (H PO , Pi) is an essential macronutrient integral to energy metabolism as well as a component of membrane lipids, nucleic acids, including ribosomal RNA, and therefore essential for protein synthesis. The Pi concentration in the solution of most soils worldwide is usually far too low for maximum growth of crops, including rice. This has prompted the massive use of inefficient, polluting, and nonrenewable phosphorus (P) fertilizers in agriculture. We urgently need alternative and more sustainable approaches to decrease agriculture's dependence on Pi fertilizers. These include manipulating crops by (a) enhancing the ability of their roots to acquire limiting Pi from the soil (i.e. increased P-acquisition efficiency) and/or (b) increasing the total biomass/yield produced per molecule of Pi acquired from the soil (i.e. increased P-use efficiency). Improved P-use efficiency may be achieved by producing high-yielding plants with lower P concentrations or by improving the remobilization of acquired P within the plant so as to maximize growth and biomass allocation to developing organs. Membrane lipid remodelling coupled with hydrolysis of RNA and smaller P-esters in senescing organs fuels P remobilization in rice, the world's most important cereal crop.

Foliar phosphorus fractions reveal how tropical plants maintain photosynthetic rates despite low soil phosphorus availability

“…Similarly, there was no response of photosynthetic rate to N and P fertilization in understorey species of a tropical plantation (Zhu, Lu, & Mo, ) or in response to P addition in lowland tropical forest understorey seedlings after 10 years of P fertilization (Pasquini & Santiago, ). The results, combined with LMA results, also agree with studies of several crop species which demonstrated that photosynthesis is far less sensitive to fertilization than leaf growth (Assuero et al, ; Chiera et al, ; Dissanayaka et al, ).…”

“…Under P deficiency, photosynthesis is generally reduced (Turnbull, Warren, & Adams, 2007) due to feedback inhibition resulting from reduced leaf growth (Dissanayaka et al, 2018) or because orthophosphate (Pi) in the cytosol becomes limiting (Warren, 2011). Plants also tend to increase their leaf mass per unit area (LMA; Chiera, Thomas, and Rufty (2002) and increase their photosynthetic P-use efficiency (Hidaka & Kitayama, 2009) when P supply is limited.…”

Phosphorus use efficiency and fertilizers: future opportunities for improvements

“…Phosphate forms a major component of fundamental biomolecules such as nucleic acids, adenosine phosphates and phospholipids. Ignoring stored vacuolar phosphorus, cellular phospholipids can account for up to a third of organic phosphorus in cells (in the order of RNA > phospholipids > phosphate-esters > DNA > phosphorylated proteins) and therefore represent a major proportion of the phosphorus budget [32,33] . Adaptive metabolic responses that release these stores can make a major contribute to plant adaption to growth under lowphosphorus conditions and represents a target for improving crop phosphorus use efficiency.…”

“…3). Metabolic adaptation and membrane remodeling enables plants to adapt to extremely low-phosphorus environments [33,34] . Yet the fundamental understanding of the processes underpinning membrane lipid exchange in crops remains limited.…”

Metabolic alterations provide insights into Stylosanthes roots responding to phosphorus deficiency

“…Remobilization of P-containing metabolites is considered as an important strategy for plants adaption to P deficiency [15]. Under P-limiting conditions, P-containing metabolites, such as nucleic acid, phospholipids and phosphorylated sugars, can be scavenged to release Pi and maintain P homeostasis in plant cells [60]. It has been shown that phosphorylated sugars are reduced by P deficiency in various plants, such as Arabidopsis [37], barley [40], white lupin (Lupinus albus) [61] and Populus cathayana [62].…”