Three-dimensional quantitative description of symbiont ultrastructure within the algal layer oftwo members of the lichen family Umbilicariaceae

Valladares, Fernando; Ascaso, Carmen

doi:10.1017/s0024282992000380

Cited by 30 publications

(5 citation statements)

References 37 publications

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“…Under field conditions, slow dehydration results in responses in the cells of lichen phycobionts that are commonly seen in both mosses and resurrection plants (angiosperms). These common responses include the shrinkage of cytoplasm and chloroplasts, accumulation of starch in thylakoids, vacuolar fragmentation, and slight withdrawal of plasmalemma from cell wall but maintenance of membrane integrity (Oliver & Bewley ; Valladares & Ascaso ; Farrant et al . ).…”

Section: Discussionmentioning

confidence: 99%

The response of Asterochloris erici (Ahmadjian) Skaloud et Peksa to desiccation: a proteomic approach

Gasulla

Jain

Barreno

et al. 2013

Plant Cell & Environment

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The study of desiccation tolerance of lichens, and of their chlorobionts in particular, has frequently focused on the antioxidant system that protects the cell against photo-oxidative stress during dehydration/rehydration cycles. In this study, we used proteomic and transcript analyses to assess the changes associated with desiccation in the isolated phycobiont Asterochloris erici. Algae were dried either slowly (5-6 h) or rapidly (<60 min), and rehydrated after 24 h in the desiccated state. To identify proteins that accumulated during the drying or rehydration processes, we employed two-dimensional (2D) difference gel electrophoresis (DIGE) coupled with individual protein identification using trypsin digestion and liquid chromatography-tandem mass spectrometry (LC-MS/ MS). Proteomic analyses revealed that desiccation caused an increase in relative abundance of only 11-13 proteins, regardless of drying rate, involved in glycolysis, cellular protection, cytoskeleton, cell cycle, and targeting and degradation. Transcripts of five Hsp90 and two b-tubulin genes accumulated primarily at the end of the dehydration process. In addition, transmission electron microscopy (TEM) images indicate that ultrastructural cell injuries, perhaps resulting from physical or mechanical stress rather than metabolic damage, were more intense after rapid dehydration. This occurred with no major change in the proteome. These results suggest that desiccation tolerance of A. erici is achieved by constitutive mechanisms.

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Section: Discussionmentioning

confidence: 99%

The response of Asterochloris erici (Ahmadjian) Skaloud et Peksa to desiccation: a proteomic approach

Gasulla

Jain

Barreno

et al. 2013

Plant Cell & Environment

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“…Semi-quantitative measurements were taken from electron micrographs. The volume density (Fv), representing the percentage of a reference volume occupied by a certain structure (Valladares & Ascaso, 1992). was calculated for major organelles and storage bodies visible in sections of the photobiont.…”

Section: Quantitative Ultrastructural Studies and Immunogold Localizamentioning

confidence: 99%

Potential effects of rising tropospheric concentrations of CO₂ and O₃ on green‐algal lichens

Balaguer

Valladares²,

Ascaso³

et al. 1996

New Phytologist

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SUMMARYParmelia sulcata Taylor was used as a model to examine the efFects of elevated CO.^ and/or O^ on green algal lichens. Tballi were exposed for 30 d in duplicate controlied-environment chambers to two atmospheric concentrations of CO^ ('ambient' [350 /(mol mol '] and 'elevated ' [700 //mol mol"'] 24 h d"') and two O,, regimes ('non-polluted' air [CF, < 5 nmol mol"'] and 'polluted' air [15nmQlmol"' overnight rising to a midday maximum of 75 nmol mol"']). in a factorial design. Elevated CO^ or elevated Oj depressed the light saturated rate of COj assimilation (-4^^,) measured at ambient CO.^ by 30 "" and 18 "", respectively. However, despite this efTect ulfrastrucfura) studies revealed increased Jipid axorage in ce]]s oi the phoEobJonr in response to CO^-enrichment. Simultaneous exposure to elevated O^ reduced CO.,-induced lipid accumulation and reduced -4,^, in an additive manner. Gold-antibody labelling revealed that the decline in photosynthetic capacity induced by elevated CO, and/or O^ was accompanied by a parallel decrease in the concentration of Rubisco in the algal pyrenoid (r = 0-93). Interestingly, differences in the amount of Rubisco protein were not correlated with changes in pyrenoid volume. Measurements of in vivo chlorophyll-fluorescence induction kinetics showed that the decline in ,4^^^ induced by elevated CO., and/or O^ was not associated with significant changes in the photochemical efficiency of photosystem (PS) II. Although the experimental conditions inevitably imposed some stress on the thalli, revealed as a significant decline in the efficiency of PS II photochemistry, and enhanced starch accumulation in the photobiont over the fumigation period, the study shows tbat tbe green-algal lichen symbiosis might be influenced by future changes in atmospheric composition. Pbotosynthetic capacity, measured at ambient CO,, was found to be reduced after a controlled 30 d exposure to elevated CO^ and/or O,^ and this efTect was associated with a parallel decline in tbe amount of Rubisco in the pyrenoid of algal chloropiasts.

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“…The use of secondary metabolites as taxonomic characters to discern species has a long history in lichenology (Brodo, 1986;W.L. Culberson, 1969;Hawksworth, 1976;Rogers, 1989;Culberson & Culberson, 1994;Lumbsch, 1998), with recent molecular studies both supporting refuting (Articus &Buschbom & Mueller, 2006;Nelsen & Gargas, 2009) their correlation with species limits. The relationship between species classification and the presence/ absence of the secondary metabolite lichexanthone has been questioned by Harris (1991Harris ( , 1995Harris ( , 1998, who concluded that this metabolite is of little use for species classification in the family, while Aptroot & al.…”

Section: Introductionmentioning

confidence: 99%

Elucidating phylogenetic relationships and genus‐level classification within the fungal family Trypetheliaceae (Ascomycota: Dothideomycetes)

Nelsen

Lücking

Aptroot³

et al. 2014

TAXON

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While the phylogenetic position of Trypetheliaceae has been the subject of recent molecular studies, the relationships within this family have been little studied. Here we construct a detailed genus‐level phylogeny of the family. We confirm previous morphology‐based findings suggesting that a substantial proportion of genera are not monophyletic, and that an overemphasis has been placed on certain character state combinations which do not strictly reflect phylogenetic relationships. Specifically, patterns of ascospore septation, ostiole orientation and type of ascomatal aggregation are evolutionarily labile, and of limited utility for the delimitation of genera as currently circumscribed. We show that species from a number of genera including Astrothelium, Bathelium, Cryptothelium, Laurera and Trypethelium together form a strongly supported group, referred to here as the “Astrothelium” clade. Species from Aptrootia, Architrypethelium, Campylothelium, Marcelaria (L. purpurina and L. cumingii groups), Pseudopyrenula and species from the Trypethelium eluteriae group fall outside of the “Astrothelium” clade and each form monophyletic groups. In contrast, species from Arthopyrenia, Mycomicrothelia and Polymeridium fall outside of the “Astrothelium” clade, and do not form monophyletic groups. The data presented here validate earlier morphology‐based findings suggesting generic delimitations are in need of revision, and provides a first step towards identifying the utility of individual characters and identifying which characters and character state combinations may be useful for future classification.

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Three-dimensional quantitative description of symbiont ultrastructure within the algal layer oftwo members of the lichen family Umbilicariaceae

Cited by 30 publications

References 37 publications

The response of Asterochloris erici (Ahmadjian) Skaloud et Peksa to desiccation: a proteomic approach

The response of Asterochloris erici (Ahmadjian) Skaloud et Peksa to desiccation: a proteomic approach

Potential effects of rising tropospheric concentrations of CO₂ and O₃ on green‐algal lichens

Elucidating phylogenetic relationships and genus‐level classification within the fungal family Trypetheliaceae (Ascomycota: Dothideomycetes)

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Three-dimensional quantitative description of symbiont ultrastructure within the algal layer oftwo members of the lichen family Umbilicariaceae

Cited by 30 publications

References 37 publications

The response of Asterochloris erici (Ahmadjian) Skaloud et Peksa to desiccation: a proteomic approach

The response of Asterochloris erici (Ahmadjian) Skaloud et Peksa to desiccation: a proteomic approach

Potential effects of rising tropospheric concentrations of CO2 and O3 on green‐algal lichens

Elucidating phylogenetic relationships and genus‐level classification within the fungal family Trypetheliaceae (Ascomycota: Dothideomycetes)

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Potential effects of rising tropospheric concentrations of CO₂ and O₃ on green‐algal lichens