Autophagy mediates hydrotropic response in Arabidopsis thaliana roots. (July 2018)

• Record Type: Journal Article
• Authors: Jiménez-Nopala, Gladys; Salgado-Escobar, Angel Eduardo; Cevallos-Porta, Diego; Cárdenas, Luis; Sepúlveda-Jiménez, Gabriela; Cassab, Gladys; Porta, Helena
• Is Part Of: Plant science. Volume 272(2018)
• Page Start: 1
• Page End: 13
• Publication Date: 2018-07
• Subjects: dpg days post germination -- NM normal or germination medium -- WSM water stress medium; Autophagy -- Root hydrotropism -- Water potential gradient -- H2O2 accumulation -- Lipid peroxidation; Botany -- Periodicals; Botanique -- Périodiques; 580
• DOI: 10.1016/j.plantsci.2018.03.026
• Languages: English
• ISSNs: 0168-9452

Abstract

Highlights: The autophagyc flux is required for the hydrotropic response. The root curvature is absent in autophagy mutants in the hydrotropic NM-WSM system. H2 O2 and autophagosomes accumulate in the root curvature at a similar time in NM-WSM system. Peroxidase activity inhibition and RBOH activity inhibition regulates root curvature. Abstract: This work shows that autophagy plays a key role in the hydrotropic curvature of Arabidopsis thaliana roots. An analysis of GFP-ATG8a transgenic plants showed that autophagosomes accumulated in the root curvature 2 h after the transfer of seedlings to Normal Medium-Water Stress Medium (NM-WSM). Autophagy flux was required for root bending. Remarkably, several atg mutants did not show hydrotropic curvature in NM-WSM or the splitting-agar system. Hyper, an H2 O2 sensor showed that H2 O2 preferentially accumulated in the root curvature at a similar rate as the autophagosomes did during hydrotropic response. Peroxidase and ROBH activity inhibition affected, negatively or positively root curvature. This data suggested H2 O2 balance was required for root bending. Malondialdehyde, a metabolite used as an indicator of oxidative stress, accumulated at the same rate during the development of the curvature in NM-WSM. These results suggest that autophagy is required for the hydrotropic response in NM-WSM. We discuss the possible regulatory role of H2 O2 on autophagy during the hydrotropic response that might relieve oxidative stress provoked by water stress. NM-WSM is water stress system suitable for studying hydrotropic responses on a short-term basis.