A Chlorophyll a/b-binding Protein Homolog That Is Induced by Iron Deficiency Is Associated with Enlarged Photosystem I Units in the Eucaryotic Alga Dunaliella salina

Varsano, Tal; Wolf, Sharon G.; Pick, Uri

doi:10.1074/jbc.m511057200

Cited by 48 publications

(43 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Under iron deWciency, transgenic plants were able to maintain leaf greenness, while control plants showed yellowing of the leaves. Several enzymatic reactions required for chlorophyll biosynthesis are Fe-dependent (Miller et al 1995); therefore, photosynthesis is highly vulnerable to iron limitation (Varsano et al 2006). Independent transgenic events expressing the Arabidopsis FRO2 protein showed signiWcantly higher chlorophyll concentrations in the leaves when compared to control (Fig.…”

Section: Discussionmentioning

confidence: 98%

Molecular and phenotypic characterization of transgenic soybean expressing the Arabidopsis ferric chelate reductase gene, FRO2

Vasconcelos

Eckert

Arahana

et al. 2006

Planta

View full text Add to dashboard Cite

Soybean (Glycine max Merr.) production is reduced under iron-limiting calcareous soils throughout the upper Midwest regions of the US. Like other dicotyledonous plants, soybean responds to iron-limiting environments by induction of an active proton pump, a ferric iron reductase and an iron transporter. Here we demonstrate that heterologous expression of the Arabidopsis thaliana ferric chelate reductase gene, FRO2, in transgenic soybean significantly enhances Fe(+3) reduction in roots and leaves. Root ferric reductase activity was up to tenfold higher in transgenic plants and was not subjected to post-transcriptional regulation. In leaves, reductase activity was threefold higher in the transgenic plants when compared to control. The enhanced ferric reductase activity led to reduced chlorosis, increased chlorophyll concentration and a lessening in biomass loss in the transgenic events between Fe treatments as compared to control plants grown under hydroponics that mimicked Fe-sufficient and Fe-deficient soil environments. However, the data indicate that constitutive FRO2 expression under non-iron stress conditions may lead to a decrease in plant productivity as reflected by reduced biomass accumulation in the transgenic events under non-iron stress conditions. When grown at Fe(III)-EDDHA levels greater than 10 microM, iron concentration in the shoots of transgenic plants was significantly higher than control. The same observation was found in the roots in plants grown at iron levels higher than 32 microM Fe(III)-EDDHA. These results suggest that heterologous expression of an iron chelate reductase in soybean can provide a route to alleviate iron deficiency chlorosis.

show abstract

Section: Discussionmentioning

confidence: 98%

Molecular and phenotypic characterization of transgenic soybean expressing the Arabidopsis ferric chelate reductase gene, FRO2

Vasconcelos

Eckert

Arahana

et al. 2006

Planta

View full text Add to dashboard Cite

show abstract

“…Fe stress responsive LHC gene products, such as CP43Ј and Tidi, which are found in cyanobacteria and green algae (22), respectively, function as peripheral light-harvesting antennas coupled to PSI reaction centers. Large-scale patterns in open ocean variable fluorescence suggest that such specialized pigment-protein complexes are typical in phytoplankton populations found in iron-limited HNLC waters (17).…”

Section: Resultsmentioning

confidence: 99%

Whole-cell response of the pennate diatom Phaeodactylum tricornutum to iron starvation

Allen

LaRoche²,

Maheswari

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

406

505

View full text Add to dashboard Cite

Marine primary productivity is iron (Fe)-limited in vast regions of the contemporary oceans, most notably the high nutrient low chlorophyll (HNLC) regions. Diatoms often form large blooms upon the relief of Fe limitation in HNLC regions despite their prebloom low cell density. Although Fe plays an important role in controlling diatom distribution, the mechanisms of Fe uptake and adaptation to low iron availability are largely unknown. Through a combination of nontargeted transcriptomic and metabolomic approaches, we have explored the biochemical strategies preferred by Phaeodactylum tricornutum at growth-limiting levels of dissolved Fe. Processes carried out by components rich in Fe, such as photosynthesis, mitochondrial electron transport, and nitrate assimilation, were down-regulated. Our results show that this retrenchment is compensated by nitrogen (N) and carbon (C) reallocation from protein and carbohydrate degradation, adaptations to chlorophyll biosynthesis and pigment metabolism, removal of excess electrons by mitochondrial alternative oxidase (AOX) and non-photochemical quenching (NPQ), and augmented Fe-independent oxidative stress responses. Iron limitation leads to the elevated expression of at least three gene clusters absent from the Thalassiosira pseudonana genome that encode for components of iron capture and uptake mechanisms.genome ͉ metabalomics ͉ photosynthesis ͉ transcriptomics ͉ nutrients

show abstract

“…In C. reinhardtii, RNAi knockout mutants of Lhca3 cause a depletion of all LHCI proteins, with the exception of Lhca2 and 9, suggesting Lhca3 is important for linking the LHCI antenna system to PSI, but whether this is a consistent role in other taxa remains to be seen (Naumann et al 2005). In Dunaliella, for instance, iron stress causes the induction of a large Lhca3 variant that effectively increases PSI antenna size, presumably to balance excitation between the photosystems (Varsano et al 2006). Overall it seems that green algae are capable of modulating the makeup and structure of the PSI-LHCI supercomplex in response to changing environmental conditions.…”

Section: Photosystem I Light-harvesting Antennaementioning

confidence: 97%

Structural and functional diversification of the light-harvesting complexes in photosynthetic eukaryotes

2010

View full text Add to dashboard Cite

Eukaryotes acquired photosynthetic metabolism over a billion years ago, and during that time the light-harvesting antennae have undergone significant structural and functional divergence. The antenna systems are generally used to harvest and transfer excitation energy into the reaction centers to drive photosynthesis, but also have the dual role of energy dissipation. Phycobilisomes formed the first antenna system in oxygenic photoautotrophs, and this soluble protein complex continues to be the dominant antenna in extant cyanobacteria, glaucophytes, and red algae. However, phycobilisomes were lost multiple times during eukaryotic evolution in favor of a thylakoid membrane-integral light-harvesting complex (LHC) antenna system found in the majority of eukaryotic taxa. While photosynthesis spread across different eukaryotic kingdoms via endosymbiosis, the antenna systems underwent extensive modification as photosynthetic groups optimized their light-harvesting capacity and ability to acclimate to changing environmental conditions. This review discusses the different classes of LHCs within photosynthetic eukaryotes and examines LHC diversification in different groups in a structural and functional context.

show abstract

A Chlorophyll a/b-binding Protein Homolog That Is Induced by Iron Deficiency Is Associated with Enlarged Photosystem I Units in the Eucaryotic Alga Dunaliella salina

Cited by 48 publications

References 40 publications

Molecular and phenotypic characterization of transgenic soybean expressing the Arabidopsis ferric chelate reductase gene, FRO2

Molecular and phenotypic characterization of transgenic soybean expressing the Arabidopsis ferric chelate reductase gene, FRO2

Whole-cell response of the pennate diatom Phaeodactylum tricornutum to iron starvation

Structural and functional diversification of the light-harvesting complexes in photosynthetic eukaryotes

Contact Info

Product

Resources

About