Sugar ratios, glutathione redox status and phenols in the resurrection species <i>Haberlea rhodopensis</i> and the closely related non‐resurrection species <i>Chirita eberhardtii</i>

Djilianov, Dimitar; Ivanov, Sergey; Moyankova, Daniela; Miteva, L.; Kirova, Elisaveta; Alexieva, V.; Joudi, Mehdi; Peshev, Darin; Ende, Wim Van den

doi:10.1111/j.1438-8677.2010.00436.x

Cited by 58 publications

(59 citation statements)

References 89 publications

(155 reference statements)

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“…7, black circles). Accumulation of Suc at RWC below 20% also has been reported to occur in other resurrection plants, such as Xerophyta humilis and Haberlea rhodopensis (Djilianov et al, 2011). During partial rehydration (approximately 50% RWC), the Suc content in C. pumilum declines significantly, reaching levels similar to that observed in predesiccated plants upon full rehydration (Fig.…”

Section: Changes In Suc Levels During Dehydration and Rehydrationsupporting

confidence: 73%

Photoprotection Conferred by Changes in Photosynthetic Protein Levels and Organization during Dehydration of a Homoiochlorophyllous Resurrection Plant

et al. 2015

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During desiccation, homoiochlorophyllous resurrection plants retain most of their photosynthetic apparatus, allowing them to resume photosynthetic activity quickly upon water availability. These plants rely on various mechanisms to prevent the formation of reactive oxygen species and/or protect their tissues from the damage they inflict. In this work, we addressed the issue of how homoiochlorophyllous resurrection plants deal with the problem of excessive excitation/electron pressures during dehydration using Craterostigma pumilum as a model plant. To investigate the alterations in the supramolecular organization of photosynthetic protein complexes, we examined cryoimmobilized, freeze-fractured leaf tissues using (cryo)scanning electron microscopy. These examinations revealed rearrangements of photosystem II (PSII) complexes, including a lowered density during moderate dehydration, consistent with a lower level of PSII proteins, as shown by biochemical analyses. The latter also showed a considerable decrease in the level of cytochrome f early during dehydration, suggesting that initial regulation of the inhibition of electron transport is achieved via the cytochrome b 6 f complex. Upon further dehydration, PSII complexes are observed to arrange into rows and semicrystalline arrays, which correlates with the significant accumulation of sucrose and the appearance of inverted hexagonal lipid phases within the membranes. As opposed to PSII and cytochrome f, the light-harvesting antenna complexes of PSII remain stable throughout the course of dehydration. Altogether, these results, along with photosynthetic activity measurements, suggest that the protection of retained photosynthetic components is achieved, at least in part, via the structural rearrangements of PSII and (likely) light-harvesting antenna complexes into a photochemically quenched state.

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Section: Changes In Suc Levels During Dehydration and Rehydrationsupporting

confidence: 73%

Photoprotection Conferred by Changes in Photosynthetic Protein Levels and Organization during Dehydration of a Homoiochlorophyllous Resurrection Plant

et al. 2015

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“…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).…”

Section: Relative Water Contentmentioning

confidence: 83%

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

Gashi

Babani

Kongjika

2013

Physiol Mol Biol Plants

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The desiccation-tolerant plants of the R. serbica and R. nathaliae are resurrection plants which are able to fully recover their physiological function after anabiosis. A comparison of chlorophyll fluorescence imaging and photosynthetic pigment contents responses of R. serbica and, for the first time, R. nathaliae to dehydration and rehydration were investigated. For this purpose, plants after collection from their natural habitats were kept fully watered for 14 days at natural condition. The experiment was conducted with mature leaves of both species. R. serbica and R. nathaliae plants were dehydrated to 5.88 % and 7.87 % relative water content (RWC) by withholding water for 15 days, afterwards the plants were rehydrated for 72 hours to 94.67 % and 97.02 % RWC. During desiccation, R. serbica plants preserved the chlorophyll content about 84 %, while R. nathaliae about 90 %. During dehydration when RWC were more than 40 %, photochemical efficiency of PSII for photochemistry, the Fv/Fm ratio, decreased about 40 % in R. nathaliae plants, but a strong reduction with 60 % was recorded for R. serbica. Following rehydration, the Fv/Fm ratio recovered more rapidly in R. nathaliae. The higher photosynthetic rates could also be detected via imaging the chlorophyll fluorescence decrease ratio Rfd, which possessed higher values after rehydration leaves of R.nathaliae as compared to R. serbica. The results showed that the photosynthetic activity and chlorophyll contents after rehydration are recovered more rapidly in R. nathaliae in comparison to R. serbica.

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“…8C). It has been reported that soluble sugars maintain high antioxidant protection, and it is one of the mechanisms in plants to cope with abiotic stress (46,47). Although there are a few reports about the role of ␤-glucosidases in abiotic stress, most of them suggest synthesis and accumulation of ABA as possible mechanisms.…”

Section: Analysis Of Gene Expression Has Often Been Useful To Gain Inmentioning

confidence: 99%

Functional Characterization of CsBGlu12, a β-Glucosidase from Crocus sativus, Provides Insights into Its Role in Abiotic Stress through Accumulation of Antioxidant Flavonols

Baba

Vishwakarma

Ashraf

2017

Journal of Biological Chemistry

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Edited by Joseph JezGlycosylation and deglycosylation are impressive mechanisms that allow plants to regulate the biological activity of an array of secondary metabolites. Although glycosylation improves solubility and renders the metabolites suitable for transport and sequestration, deglycosylation activates them to carry out biological functions. Herein, we report the functional characterization of CsBGlu12, a ␤-glucosidase from Crocus sativus. CsBGlu12 has a characteristic glucoside hydrolase 1 family (␣/␤) 8 triose-phosphate isomerase (TIM) barrel structure with a highly conserved active site. In vitro enzyme activity revealed that CsBGlu12 catalyzes the hydrolysis of flavonol ␤-glucosides and cello-oligosaccharides. Site-directed mutagenesis of any of the two conserved catalytic glutamic acid residues (Glu 200 and Glu 414 ) of the active site completely abolishes the ␤-glucosidase activity. Transcript analysis revealed that Csbglu12 is highly induced in response to UV-B, dehydration, NaCl, methyl jasmonate, and abscisic acid treatments indicating its possible role in plant stress response. Transient overexpression of CsBGlu12 leads to the accumulation of antioxidant flavonols in Nicotiana benthamiana and confers tolerance to abiotic stresses. Antioxidant assays indicated that accumulation of flavonols alleviated the accretion of reactive oxygen species during abiotic stress conditions. ␤-Glucosidases are known to play a role in abiotic stresses, particularly dehydration through abscisic acid; however, their role through accumulation of reactive oxygen species (ROS) scavenging flavonols has not been established. Furthermore, only one ␤-glucosidase 12 homolog has been characterized so far. Therefore, this work presents an important report on characterization of CsBGlu12 and its role in abiotic stress through ROS scavenging.Plants are sessile organisms that cannot escape their predators and the harsh environmental conditions. However, during the course of evolution, plants have learned to defend themselves and adapt to different types of biotic and abiotic stresses by synthesizing a diverse assortment of secondary metabolites. Many of these secondary metabolites are stored in inactive glycosylated forms. The glycosylation chemically stabilizes and enhances the solubility of the metabolites and renders them fit for storage in the vacuole and more so to protect the plant from the noxious effects of its own defense system (1). These glyconjugates are activated by the hydrolysis of the ␤-glucosidic bond by a class of enzymes called ␤-glucosidases. ␤-Glucosidases (EC 3.2.1.2.1) belong to family 1 of glycoside hydrolases and perform diverse and vital functions in plants, which include, but are not limited to, the activation of lignin precursors (2), release of glucose from oligosaccharides (3), release of phytohormones from inactive glycosides (4), and activation of several defense compounds (5-9). This process of glycosylation and deglycosylation offers an efficient mechanism that regulates the homeostasis of secon...

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Sugar ratios, glutathione redox status and phenols in the resurrection species Haberlea rhodopensis and the closely related non‐resurrection species Chirita eberhardtii

Cited by 58 publications

References 89 publications

Photoprotection Conferred by Changes in Photosynthetic Protein Levels and Organization during Dehydration of a Homoiochlorophyllous Resurrection Plant

Photoprotection Conferred by Changes in Photosynthetic Protein Levels and Organization during Dehydration of a Homoiochlorophyllous Resurrection Plant

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

Functional Characterization of CsBGlu12, a β-Glucosidase from Crocus sativus, Provides Insights into Its Role in Abiotic Stress through Accumulation of Antioxidant Flavonols

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