Enhancing phosphorus and zinc acquisition efficiency in rice: a critical review of root traits and their potential utility in rice breeding

Abstract

BackgroundRice is the world's most important cereal crop and phosphorus (P) and zinc (Zn) deficiency are major constraints to its production. Where fertilizer is applied to overcome these nutritional constraints it comes at substantial cost to farmers and the efficiency of fertilizer use is low. Breeding crops that are efficient at acquiring P and Zn from native soil reserves or fertilizer sources has been advocated as a cost-effective solution, but would benefit from knowledge of genes and mechanisms that confer enhanced uptake of these nutrients by roots.ScopeThis review discusses root traits that have been linked to P and Zn uptake in rice, including traits that increase mobilization of P/Zn from soils, increase the volume of soil explored by roots or root surface area to recapture solubilized nutrients, enhance the rate of P/Zn uptake across the root membrane, and whole-plant traits that affect root growth and nutrient capture. In particular, this review focuses on the potential for these traits to be exploited through breeding programmes to produce nutrient-efficient crop cultivars.ConclusionsFew root traits have so far been used successfully in plant breeding for enhanced P and Zn uptake in rice or any other crop. Insufficient genotypic variation for traits or the failure to enhance nutrient uptake under realistic field conditions are likely reasons for the limited success. More emphasis is needed on field studies in mapping populations or association panels to identify those traits and underlying genes that are able to enhance nutrient acquisition beyond the level already present in most cultivars.

The Physiology of Adventitious Roots

“…3). Rice has 13 known phosphate transporters and an additional 13 putative transporters (Rose et al, 2013). Upon detection of low nutrient levels, the expression of these transporter genes increases to improve uptake capacity.…”

“…Increases in phosphorus uptake with shallower roots also corresponded with increased yield in bean (Bonser et al, 1996;Liao et al, 2001;Richardson et al, 2011), so improvements in phosphorus efficiency could be achieved by selecting shallower root systems. However, the tradeoff with shallow roots is a reduction in drought tolerance because the deeper soil layers contain more water, so the ideal scenario for tolerating drought and phosphorus deficiency is a combination of deep and shallow roots (Uga et al, 2011(Uga et al, , 2012Rose et al, 2013). Recent identification of quantitative trait loci for both shallow and deep rooting in rice (Uga et al, 2011(Uga et al, , 2012 and bean (Liao et al, 2004;Richardson et al, 2011) suggest that this may be a real possibility (Rose et al, 2013).…”

Phosphorus and Zinc Interaction Influence Leaf Area Index in Fine vs. Coarse Rice (Oryza sativa L) Genotypes in Northwest Pakistan

“…The desire to improve the Zn and P acquisition efficiency of rice roots arises because P and Zn fertilizers are not always adequate to overcome the crop production constraints. Fertilizers are a costly input, such that their use limits the profitability of rice farming for high-input or low-input systems, and the use of fertilizers for these two rice nutrients is notoriously inefficient (Rose et al, 2013). Phosphorus is the most important element which interferes on zinc uptake by plants.…”

Eksplorasi Lokus Pup1 Berbasis Marka Molekuler pada 55 Genotipe Padi

“…Gejala pada fase vegetatif awal dapat menjadi acuan dalam strategi pemupukan untuk mengurangi kerusakan akibat kekurangan P tersebut (Chen et al, 2014). Kekurangan pasokan P pada fase generatif akan menyebabkan pembentukan gabah tidak sempurna, sehingga banyak gabah menjadi hampa dan mengakibatkan terjadinya penurunan hasil (Rose et al, 2013).…”