Characterization of oxidative and antioxidative events during dehydration and rehydration of resurrection plant Ramonda nathaliae

Abstract

In order to investigate changes of oxidative status in relation to the activity of the various protective mechanisms in resurrection plant Ramonda nathaliae, we have analysed time and relative water content (RWC) related changes in lipid peroxidation and ion leakage, hydrogen peroxide accumulation, changes of pigment content and antioxidative enzyme activity, together with expression of dehydrins. The results indicate that enhanced oxidative status during dehydration, not previously reported for resurrection plants, could play an active role in inducing the desiccation adaptive response in R. nathaliae. A critical phase is shown to exist during dehydration (in the range of RWC between 50 and 70%) during which a significant increase in hydrogen peroxide accumulation, lipid peroxidation and ion leakage, accompanied by a general decline in antioxidative enzyme activity, takes place. This phase is designated as a transition characterized by change in the type of stress response. The initial response, relying mainly on the enzymatic antioxidative system, is suspended but more effective, desiccation specific protective mechanisms, such as expression of dehydrins, are then switched on. The expression of dehydrins in R. nathaliae could be inducible as well as constitutive. In order to cope with the oxidative stress associated with rapid rewatering, R. nathaliae reactivated antioxidative enzymes. We propose that controlled elevation of reactive oxygen species, such as hydrogen peroxide, could be an important mechanism enabling resurrection plants to sense dehydration and to trigger an adaptive programme at an appropriate stage during the dehydration/rehydration cycle.

Chlorophyll fluorescence imaging of photosynthetic activity and pigment contents of the resurrection plants Ramonda serbica and Ramonda nathaliae during dehydration and rehydration

“…Degl'Innocenti et al (2008) showed that in R. serbica, the RWC decreased from values of 97 % in fully hydrated control plants to values of only 7 % after 2 weeks dehydration. In addition, the RWC of R. nathaliae decreased from 94.5 % to 3.6 % during dehydration (Jovanoviç et al 2011). Kinetics of relative water content during dehydration-rehydration cycle was reported from other authors in R. serbica (Augusti et al 2001;Quartacci et al 2002;Veljovic-Jovanoviç et al 2006;Sgherri et al 2004) and Haberlea rhodopensis (Nagy- Deri et al 2011;Mihailova et al 2011;Djilianov et al 2011;Georgieva et al 2010).…”

“…Previous investigation of R. serbica and R. nathaliae has brought the evidence to adaptive features necessary to preserve cell membrane integrity (Quartacci et al 2002), antioxidative capacity (Sgherri et al 2004;Jovanoviç et al 2011), photosynthetic activity (Tuba et al 1998), CO 2 fixation and chlorophyll a fluorescence (Degl'Innocenti et al 2008), genome size variation and polyploidy (Siljak-Yakovlev et al 2008), osmotic adjustment (Zivkoviç et al 2005), seed germination (Gashi et al 2012a) and in vitro cultivation from seeds of Ramonda plants (Kongjika et al 2002;Gashi et al 2011;Dontcheva et al 2009;Daskalova et al 2012). …”

Orthodox Seeds and Resurrection Plants: Two of a Kind?

“…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). In the angiosperm resurrection species Ramonda nathaliae (an HDT), a time-course analysis of different antioxidant enzyme activities revealed the sequential involvement of these enzymes in dehydration and subsequent rehydration (Jovanovic et al, 2011).…”

“…In Arabidopsis seeds and X. viscosa leaves, LEA proteins are broadly distributed in subcellular compartments, reflecting their protective role in the various cellular membranes (Candat et al, 2014;Costa et al, 2017). LEA genes are dehydration inducible and are constitutively expressed in resurrection species (Rodriguez et al, 2010;Jovanovic et al, 2011;Gechev et al, 2013;Giarola et al, 2015a;Costa et al, 2017). The expression of LEA genes from C. plantagineum increases upon early or partial dehydration (Rodriguez et al, 2010;Giarola et al, 2015a).…”

Micropropagation and in vitro conservation of the rare and threatened plants Ramonda serbica and Ramonda nathaliae

“…In recent study, the resurrection plants from Ramonda genus have become important models for studying drought tolerance (Quartacci et al 2002;Veljovic-Jovanovic et al 2006;Gashi et al 2013a), photosynthetic abilities during transition from anabiosis (Augusti et al, 2001;Degl'Innocenti et al 2008;Gashi et al, 2013a), antioxidative capacity (Sgherri et al 2004;Jovanovic et al 2011) and other specialized and multidisciplinary studies. Other authors have reported a genetic (polyploidy) and morphologic diversity within and between plants of genus Ramonda populations (Siljak-Yakovlev et al 2008;Daskalova et al 2012;Gashi et al 2013b;Gashi 2013).…”