The Combined Effect of Heat and Osmotic Stress on Suberization of Arabidopsis Roots

Abstract

The simultaneous occurrence of heat stress and drought is becoming more regular as a consequence of climate change, causing extensive agricultural losses. The application of either heat or osmotic stress increase cell-wall suberization in different tissues, which may play a role in improving plant resilience. In this work, we studied how the suberization process is affected by the combination of drought and heat stress by following the expression of suberin biosynthesis genes, cell-wall suberization and the chemical composition in Arabidopsis roots. The Arabidopsis plants used in this study were at the onset of secondary root development. At this point, one can observe a developmental gradient in the main root, with primary development closer to the root tip and secondary development, confirmed by the suberized phellem, closer to the shoot. Remarkably, we found a differential response depending on the root zone. The combination of drought and heat stress increased cell wall suberization in main root segments undergoing secondary development and in lateral roots (LRs), while the main root zone, at primary development stage, was not particularly affected. We also found differences in the overall chemical composition of the cell walls in both root zones in response to combined stress. The data gathered showed that, under combined drought and heat stress, Arabidopsis roots undergo differential cell wall remodeling depending on developmental stage, with modifications in the biosynthesis and/or assembly of major cell wall components.

Disruption of the ABA1 encoding zeaxanthin epoxidase caused defective suberin layers in Arabidopsis seed coats

“…Data from the eFP browser database ( ) showed that the expression of MYB107 , MYB9 , FAR4 , FAR5 , CYP86B1 , GPAT5 , ASFT , LTPG15 , ABCG6 , ABCG20 , and ABCG23 was induced in Arabidopsis seedlings after 3 h of 10 µM ABA treatment ( Figure S4 ). Exogenous ABA treatment was also found to induce expression of the fluorescent protein-encoding gene mCITRINE-SYP122 in Arabidopsis roots under the control of the GPAT5 promoter ( Barberon et al., 2016 ; Shukla et al., 2021 ; Leal et al., 2022 ). In kiwifruit, the expression of AchnMYB107 , which is a homologue of AtMYB107 , is increased in response to exogenous ABA treatment, followed by the induction of AchnCYP86A1 and AchnFAR expression, which are speculated to encode a fatty acid ω-hydroxylase and fatty acyl reductase, respectively, responsible for wound suberization in kiwifruit ( Wei et al., 2020a ; Wei et al., 2020b ).…”