Time-lapse Analysis of Root Reorientation in Arabidopsis: Effects of Genotype and Medium

Video: https://youtu.be/KNNL8cd5S0A

During the progression of root in soil, root cap cells are the first to encounter obstacles and are known to sense environmental cues, thus making the root cap a potential mechanosensing site. In this study, a two-layered growth medium system was developed in order to study root responses to variations in the physical strength of the medium and the importance of the root cap in the establishment of these responses. Root growth and trajectory of primary roots of Arabidopsis seedlings were investigated using in vivo image analysis. After contact with the harder layer of the medium, the root either penetrated it or underwent rapid curvature, thus enabling reorientation of growth. We initially hypothesized that the root-cap structure would affect apex penetration and reorientation, with pointed caps facilitating and domed caps impeding root penetration. This hypothesis was investigated by analysing the responses of Arabidopsis mutants with altered root caps. The primary root of lines of the fez-2 mutant, which has fewer root-cap cell layers and a more pointed root cap than wild-type roots, showed impaired penetration ability. Conversely, smb-3 roots, which display a rectangular-shaped cap, showed enhanced penetration abilities. These results, which contradict our original hypothesis, reveal a role for resistance to buckling in determining root penetration abilities.

This video compilation showcases time-lapse movies of Arabidopsis thaliana root reorientation under different conditions. Observe the dynamic behavior of wild-type and mutant roots (smb-3 and fez-2) in response to varying media (0.2/0.3 and 0.2/0.5). Witness diverse growth patterns, including step-like and wavy formations, providing valuable insights into root gravitropism and the underlying molecular mechanisms.

Keywords: Arabidopsis thaliana, Root growth, Plant development, Time-lapse, Microscopy, Plant biology

Citation:

J Roué, H Chauvet, N Brunel-Michac, F Bizet, B Moulia, E Badel, V Legué, Root cap size and shape influence responses to the physical strength of the growth medium in Arabidopsis thaliana primary roots, Journal of Experimental Botany, Volume 71, Issue 1, 1 January 2020, Pages 126–137, https://doi.org/10.1093/jxb/erz418

Published on: 04 November 2019

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