Desiccation tolerance.

Abstract

Desiccation tolerance is the ability to survive loss of 90% of cellular water or dehydration to water concentrations of <0.1g HrO g-1 dry mass. It is relatively common in reproductive stru such as seeds (termed orthodox), but is rare in vegetative tissues, occurring in some 350 spe higher plants (termed 'resurrection plants'). In this chapter we present an overview of the s associated with desiccation and review the current mechanisms proposed to explain how or seeds and resurrection plants tolerate such water Ioss. Physiological, biochemical and molecula esses involved in protection from mechanical stress, oxidative damage and metabolic disruptio

Extremophyte adaptations to salt and water deficit stress

“…Such an approach would typically take into consideration changes in the transcriptome, proteome, metabolome and lipidome, contextualised by input from biochemical, biophysical and physiological studies. To date, this has not been fully achieved for any one species, although considerable information is available for at least 12 different resurrection plant species (reviewed in Farrant et al 2012;Dinakar and Bartels 2013). Such studies have revealed common (presumably conserved) strategies among species, but yet with individual differences among them, which collectively ameliorate the stresses associated with extreme water deficit and ultimately enable a stable metabolically quiescent state in air dry tissues.…”

Orthodox Seeds and Resurrection Plants: Two of a Kind?

“…In HDT, the leaf area exposed to light (for example) is reduced via leaf curling, the presence of reflective hairs, and anthocyanin accumulation ( Fig. 1; Challabathula et al, 2016;Farrant et al, 2017). On the other hand, under dehydration stress, PDT (see Box 1; Fig.…”

“…The protein storage vacuoles found in orthodox seeds are thought to be very similar to the vacuoles found in resurrection plants, although the nature of the contents can differ among species ( Fig. 2; for review, see Farrant et al, 2017). For example, in the resurrection species Eragrostis Figure 2.…”

“…In both seeds and vegetative tissues of angiosperm resurrection plants, most mechanisms associated with subcellular protection against water deficit are induced (for review, see Farrant et al, 2012;Dinakar and Bartels, 2013;Farrant et al, 2017), rather than being constitutive, as is the case in ancestors of land plants (Oliver et al, 2000(Oliver et al, , 2005. Thus, the rate of drying is important in the institution of such protection mechanisms.…”

“…Therefore, ROS levels must be tightly controlled in the cell via enzymatic and nonenzymatic ROS-scavenging systems Sano et al, 2016). Seeds and resurrection plants use a complex array of inherent antioxidant molecules to protect themselves from abiotic stress, such as superoxide dismutases, catalases, glutathione and ascorbate peroxidases, flavonoids, and tocopherols (Illing et al, 2005;Djilianov et al, 2011;Dinakar and Bartels, 2012;Gechev et al, 2013;Sano et al, 2016;Farrant et al, 2017). In angiosperm resurrection plants, genes encoding antioxidant enzymes are either constitutively expressed or induced by drought (;50% RWC), particularly desiccation (Dinakar and Bartels, 2012;Gechev et al, 2013;Farrant et al, 2015).…”