Plant roots sense soil compaction through restricted ethylene diffusion.

Bipin K Pandey,Karin Ljung,Laurentius A C J Voesenek,Sacha J Mooney,Guoqiang Huang,Jonathan P Lynch,Michal Karady,Rahul Bhosale,Sjon Hartman,Kathleen M Brown,Olivier C Martin,Lottie Jose,Dabing Zhang,Craig J Sturrock,William R Whalley,Malcolm J Bennett

doi:10.1126/science.abf3013

Abstract

Soil compaction represents a major challenge for modern agriculture. Compaction is intuitively thought to reduce root growth by limiting the ability of roots to penetrate harder soils. We report that root growth in compacted soil is instead actively suppressed by the volatile hormone ethylene. We found that mutant Arabidopsis and rice roots that were insensitive to ethylene penetrated compacted soil more effectively than did wild-type roots. Our results indicate that soil compaction lowers gas diffusion through a reduction in air-filled pores, thereby causing ethylene to accumulate in root tissues and trigger hormone responses that restrict growth. We propose that ethylene acts as an early warning signal for roots to avoid compacted soils, which would be relevant to research into the breeding of crops resilient to soil compaction.

Highlights

Laboratory of Growth Regulators, Institute of Experimental Botany of the Czech Academy of Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish
Ethylene concentrations outside the root could increase due to the reduction in soil pore space in compacted soil, impacting gas diffusion from root tissues
In agreement with model assumptions, restricting gas diffusion from root tip tissues triggered a rapid and sustained increase in EIN3-GFP in root elongation zone cell nuclei compared to controls

Summary

Introduction

Ethylene concentrations outside the root could increase due to the reduction in soil pore space in compacted soil, impacting gas diffusion from root tissues To test this ‘restricted gas diffusion’ model, we used the EIN3-GFP Arabidopsis ethylene response reporter In agreement with model assumptions, restricting gas diffusion from root tip tissues triggered a rapid and sustained increase in EIN3-GFP in root elongation zone cell nuclei compared to controls

Results

Conclusion