ABSTRACT
Vegetative desiccation tolerance is a complex trait that is linked to the colonisation of the land during plant evolution. Resurrection plants are so named because their vegetative tissues, including the cell walls that constitute them, can survive reversible desiccation. Several cell wall adaptations have been implicated in permitting desiccation tolerance in different tissues including xyloglucan remodelling and arabinosylation of pectin and hemicellulose polymers. A role for pectin arabinans in vegetative desiccation tolerance has been established by experiments and reported in the literature. Mannans have been found to be modified in desiccation-tolerant spike mosses during desiccation. More recent studies have implicated glycine-rich proteins in forming wall-associated kinase and pectin complexes in the walls of angiosperm resurrection plants. This in turn implicates these complexes in a signal transduction capacity and plays a role in cell wall integrity signalling during dehydration. However, there remains a lack of focus on mechanisms associated with cell wall stability during desiccation–rehydration cycling. In this chapter, we highlight arabinogalactan proteins as promising candidates for future research in the context of drought resistance. We propose that GRP–WAK–FERONIA–pectin–calcium complexes form calcium stores in the cell wall upon desiccation. These stores are then able to liberate their calcium as a cytosolic burst upon rehydration to drive growth and development.
