An international research team, led by scientists from the Shanghai Jiao Tong University and University of Nottingham has discovered how plant roots sense soil hardness, and the research result was published on Science, a premier global weekly journal. The research illustrates how the plant signal ‘ethylene’ causes roots to stop growing in hard soils, but after this signal is disabled, roots are able to push through compacted soil. Scientists have discovered a signal that causes roots to stop growing in hard soils which can be ‘switched off’ to allow them to punch through compacted soil - a discovery that could help plants to grow in even the most damaged soils. Prof. Dabing ZHANG and post-doctoral fellow Dr. Guoqiang HUANG from School of Life Sciences and Biotechnology are co-corresponding author and co-first author, respectively.

Hard (compacted) soils represent a major challenge facing modern agriculture that can reduce crop yields over 50% by reducing root growth, causing significant losses annually. Soil compaction triggers a reduction in root penetration and uptake of water and nutrients (Figure 1). Despite its clear importance for agriculture and global food security, the mechanism underpinning root compaction responses has been unclear until now.

Figure 1 The different between hard and soft soils.

(A)  3D-structure image of soft soil; (B) 3D-structure image of hard soil.

From 1854, scientists try to explore the regulatory mechanism of plant roots respond to soil hardness. Passive response is believed to be adopted by plants in this process. While, this work found that roots continued growing in very hard soils when the ethylene signal was switched off. A new model was proposed by these scientists that plant roots sense soil hardness via the redistricted ethylene (Figure 2). The similar mechanism was found in Arabidopsis, Wheat, Rice and Maize. The potential for new crops that can now go deeper in soils and capture previously unavailable resources is rather inspiring!

Figure 2 work model

(A) Rice roots grow in soft soil; (B)Rice roots grow in hard soil.

This work was supported by National Key Technologies Research and Development Program of China, Ministry of Science and Technology (grant nos. 2016YFD0100804 and 2016YFE0101000), the National Natural Science Foundation of China (grant nos. 31970803 and 31861163002), China Postdoctoral Science Foundation Project (2019M661486) and Shanghai Post-doctoral Excellent Program (2018063)

Full text link: https://science.sciencemag.org/cgi/doi/10.1126/science.abf3013