The xerobranching response represses lateral root formation when roots are not in contact with water

Orman-Ligeza, Beata; Morris, Emily C.; Parizot, Boris; Lavigne, Tristan; Bab�, Aurelie; Ligeza, Aleksander; Klein, Stephanie; Sturrock, Craig; Xuan, Wei; Nov�k, Ond?ey; Ljung, Karin; Fernandez, Maria; Rodriguez, Pedro L.; Dodd, Ian C.; De Smet, Ive; Chaumont, Francois; Batoko, Henri; P�rilleux, Claire; Lynch, Jonathan P.; Bennett, Malcolm J.; Beeckman, Tom; Draye, Xavier

Abstract

© 2018 Elsevier Ltd Efficient soil exploration by roots represents an important target for crop improvement and food security [1, 2]. Lateral root (LR) formation is a key trait for optimizing soil foraging for crucial resources such as water and nutrients. Here, we report an adaptive response termed xerobranching, exhibited by cereal roots, that represses branching when root tips are not in contact with wet soil. Non-invasive X-ray microCT imaging revealed that cereal roots rapidly repress LR formation as they enter an air space within a soil profile and are no longer in contact with water. Transcript profiling of cereal root tips revealed that transient water deficit triggers the abscisic acid (ABA) response pathway. In agreement with this, exogenous ABA treatment can mimic repression of LR formation under transient water deficit. Genetic analysis in Arabidopsis revealed that ABA repression of LR formation requires the PYR/PYL/RCAR-dependent signaling pathway. Our findings suggest that ABA acts as the key signal regulating xerobranching. We conclude that this new ABA-dependent adaptive mechanism allows roots to rapidly respond to changes in water availability in their local micro-environment and to use internal resources efficiently. Orman-Ligeza et al. report that lateral root formation is repressed in soil air spaces. This novel adaptive response appears to be regulated by the abiotic stress signal ABA. They propose that this mechanism enables plants to fine-tune root branching to local variation in soil structure and water availability.

• Journal Article Type: Article
• Acceptance Date: Jul 23, 2018
• Online Publication Date: Sep 27, 2018
• Publication Date: Oct 8, 2018
• Deposit Date: Aug 3, 2018
• Publicly Available Date: Sep 28, 2019
• Journal: Current Biology
• Print ISSN: 0960-9822
• Publisher: Elsevier (Cell Press)
• Peer Reviewed: Peer Reviewed
• Volume: 28
• Issue: 19
• Pages: 3165-3173.e5
• DOI: https://doi.org/10.1016/j.cub.2018.07.074
• Keywords: Lateral roots, soil air spaces, water deficit, root system architecture, abscisic acid, auxin, cereal crops, Arabidopsis
• Public URL: https://nottingham-repository.worktribe.com/output/927165
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S0960982218310042?dgcid=rss_sd_all
• Additional Information: This article is maintained by: Elsevier; Article Title: The Xerobranching Response Represses Lateral Root Formation When Roots Are Not in Contact with Water; Journal Title: Current Biology; CrossRef DOI link to publisher maintained version: https://doi.org/10.1016/j.cub.2018.07.074; Content Type: article; Copyright: © 2018 Elsevier Ltd.