Investigating Cell Wall Modifications in Tobacco Cotyledons: Impacts of Salt and Drought Stress on Cellulose and Pectin Dynamics

Abstract

Drought and soil salinity present significant challenges to global agriculture, threatening crop yields and food security. This study investigates the structural responses of tobacco (Nicotiana tabacum SR-1) cotyledons to salt and drought stress, focusing on the remodelling of cellulose and pectins, major cell wall components. Cell wall nano-imaging using the atomic force microscopy showed that diameter of the cellulose microfibrils was significantly decreased under stress conditions, in response to stress. Confocal microscopy coupled with immunolocalization techniques, showed interesting changes in distribution of homogalacturonan (HG) pectins in the cotyledon cell wall of stressed plants compared to control conditions. While cell walls of plants grown under NaCl stress showed decrease in both de-esterified and methyl-esterified HG, which are essential for the cell wall integrity, plants grown on polyethylene glycol media, which simulated drought stress, exhibited observable increase in DE-HG. This could be a part of potential mechanism for drought resistance mediated via cell wall remodelling and strengthening through overproduction of HG, however additional research is needed to confirm and elucidate these findings. Our findings provide potential insights that may inform the development of crop varieties with improved resistance to abiotic stresses.