Nitrate Modulates Lateral Root Formation by Regulating the Auxin Response and Transport in Rice.

Bobo Wang,Xuejiao Qi,Xiaoli Guo,Huwei Sun,Xiuli Zhu,Yali Zhang,Quanzhi Zhao,Fan Feng,Dan Han

doi:10.3390/genes12060850

Bobo Wang, Xuejiao Qi + Show 7 more

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https://doi.org/10.3390/genes12060850

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Abstract

Nitrate () plays a pivotal role in stimulating lateral root (LR) formation and growth in plants. However, the role of in modulating rice LR formation and the signalling pathways involved in this process remain unclear. Phenotypic and genetic analyses of rice were used to explore the role of strigolactones (SLs) and auxin in -modulated LR formation in rice. Compared with ammonium (), stimulated LR initiation due to higher short-term root IAA levels. However, this stimulation vanished after 7 d, and the LR density was reduced, in parallel with the auxin levels. Application of the exogenous auxin α-naphthylacetic acid to -treated rice plants promoted LR initiation to levels similar to those under at 7 d; conversely, the application of the SL analogue GR24 to -treated rice inhibited LR initiation to levels similar to those under supply by reducing the root auxin levels at 10 d. D10 and D14 mutations caused loss of sensitivity of the LR formation response to . The application of and GR24 downregulated the transcription of PIN-FORMED 2 (PIN2), an auxin efflux carrier in roots. LR number and density in pin2 mutant lines were insensitive to treatment. These results indicate that LR formation by affecting the auxin response and transport in rice, with the involvement of SLs.

Highlights

IntroductionPlants have various mechanisms to adapt to nutrient supply conditions, especially plastic root development [1,2,3,4,5,6,7]
Published: 1 June 2021Plants have various mechanisms to adapt to nutrient supply conditions, especially plastic root development [1,2,3,4,5,6,7]
The lateral root (LR) density of d mutants was less responsive to NO3 supply, resulting in a greater LR density, compared with WT plants regardless of the treatment at 10 d (Figure 4A). These results suggest that SLs are involved in NO-3 -modulated LR formation in rice

Summary

Introduction

Plants have various mechanisms to adapt to nutrient supply conditions, especially plastic root development [1,2,3,4,5,6,7]. Changes in N supplied in the nutrient medium induce plasticity in LR initiation and elongation [5,11,12,13,14]. Studies of an Arabidopsis nitrate reductase double mutant suggested that the local stimulation of LR elongation is a consequence of the NO3− ion acting as a signal rather than a nutrient. Auxin plays a dominant role in the specification of founder cells that give rise to LR initiation and the later stages of LR development and is involved in NO3− -modulated LR growth [10,13,14,20,21]

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