Cell wall changes during the formation of aerenchyma in sugarcane roots


Leite D., Grandis A., Tavares E., Piovezani A., Pattathil S., Avci U. , ...More

Annals of Botany, vol.120, no.5, pp.693-708, 2017 (Journal Indexed in SCI Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 120 Issue: 5
  • Publication Date: 2017
  • Doi Number: 10.1093/aob/mcx050
  • Title of Journal : Annals of Botany
  • Page Numbers: pp.693-708
  • Keywords: Aerenchyma, arabinoxylan, bioenergy, cell wall, cellulose, glycome profile, hemicellulose, pectin, Saccharum, xyloglucan, β-glucan

Abstract

©The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company.• Background and Aims Aerenchyma develops in different plant organs and leads to the formation of intercellular spaces that can be used by the plant to transport volatile substances. Little is known about the role of cell walls in this process, although the mechanism of aerenchyma formation is known to involve programmed cell death and some cell wall modifications. We assessed the role that cell wall-related mechanisms might play in the formation of aerenchyma in sugarcane roots. • Methods Sections of roots (5 cm) were subjected to microtomography analysis. These roots were divided into 1- cm segments and subjected to cell wall fractionation. We performed analyses of monosaccharides, oligosaccharides and lignin and glycome profiling. Sections were visualized by immunofluorescence and immunogold labelling using selected monoclonal antibodies against polysaccharide epitopes according to the glycome profiles. • Key Results During aerenchyma formation, gas spaces occupied up to 40 % of the cortex cross-section within the first 5 cm of the root. As some of the cortex cells underwent dissolution of the middle lamellae, leading to cell separation, cell expansion took place along with cell death. Mixed-linkage β-glucan was degraded along with some homogalacturonan and galactan, culminating in the formation of cell wall composites made of xyloglucan, arabinoxylans, cellulose and possibly lignin. • Conclusion The composites formed seem to play a role in the physical-chemical properties of the gas chambers, providing mechanical resistance to forces acting upon the root and at the same time decreasing permeability to gases.