72 research outputs found
Comparative transcriptomics reveals the role of altered energy metabolism in the establishment of single-cell C4 photosynthesis in Bienertia sinuspersici
Single-cell C4 photosynthesis (SCC4) in terrestrial plants without Kranz anatomy involves three steps: initial CO2 fixation in the cytosol, CO2 release in mitochondria, and a second CO2 fixation in central chloroplasts. Here, we investigated how the large number of mechanisms underlying these processes, which occur in three different compartments, are orchestrated in a coordinated manner to establish the C4 pathway in Bienertia sinuspersici, a SCC4 plant. Leaves were subjected to transcriptome analysis at three different developmental stages. Functional enrichment analysis revealed that SCC4 cycle genes are coexpressed with genes regulating cyclic electron flow and amino/organic acid metabolism, two key processes required for the production of energy molecules in C3 plants. Comparative gene expression profiling of B. sinuspersici and three other species (Suaeda aralocaspica, Amaranthus hypochondriacus, and Arabidopsis thaliana) showed that the direction of metabolic flux was determined via an alteration in energy supply in peripheral chloroplasts and mitochondria via regulation of gene expression in the direction of the C4 cycle. Based on these results, we propose that the redox homeostasis of energy molecules via energy metabolism regulation is key to the establishment of the SCC4 pathway in B. sinuspersici
Release of SOS2 kinase from sequestration with GIGANTEA determines salt tolerance in Arabidopsis
Kim, Woe-Yeon et al.--Environmental challenges to plants typically entail retardation of vegetative growth
and delay or cessation of flowering. Here we report a link between the flowering time
regulator, GIGANTEA (GI), and adaptation to salt stress that is mechanistically based
on GI degradation under saline conditions, thus retarding flowering. GI, a switch in
photoperiodicity and circadian clock control, and the SNF1-related protein kinase SOS2
functionally interact. In the absence of stress, the GI:SOS2 complex prevents SOS2-
based activation of SOS1, the major plant Na+/H+-antiporter mediating adaptation to
salinity. GI over-expressing, rapidly flowering, plants show enhanced salt sensitivity,
whereas gi mutants exhibit enhanced salt tolerance and delayed flowering. Salt-induced
degradation of GI confers salt tolerance by the release of the SOS2 kinase. The GISOS2
interaction introduces a higher order regulatory circuit that can explain in
molecular terms, the long observed connection between floral transition and adaptive
environmental stress tolerance in Arabidopsis.This research was supported by the Next-Generation
BioGreen 21 Program (Systems and Synthetic Agrobiotech Center, no. PJ008025), a Cooperative Research Program for Agriculture Science & Technology Development
(Project No. PJ007850), and the Ministry of Education, Science and Technology for the
World Class University (WCU) program (R32-10148) from the Rural Development
Administration, Republic of Korea, and by grant BIO2009-08641 financed by the
Spanish Ministry of Science and Innovation and the FEDER program.Peer reviewe
TsHKT1;2, a HKT1 homolog from the extremophile arabidopsis relative Thellungiella salsuginea, shows K \u3csup\u3e+\u3c/sup\u3e specificity in the presence of NaCl
Cellular Na +/K + ratio is a crucial parameter determining plant salinity stress resistance. We tested the function of plasma membrane Na +/K + cotransporters in the High-affinity K + Transporter (HKT) family from the halophytic Arabidopsis (Arabidopsis thaliana) relative Thellungiella salsuginea. T. salsuginea contains at least two HKT genes. TsHKT1;1 is expressed at very low levels, while the abundant TsHKT1;2 is transcriptionally strongly up-regulated by salt stress. TsHKT-based RNA interference in T. salsuginea resulted in Na + sensitivity and K + deficiency. The athkt1 mutant lines overexpressing TsHKT1;2 proved less sensitive to Na + and showed less K + deficiency than lines overexpressing AtHKT1. TsHKT1;2 ectopically expressed in yeast mutants lacking Na + or K + transporters revealed strong K + transporter activity and selectivity for K + over Na +. Altering two amino acid residues in TsHKT1;2 to mimic the AtHKT1 sequence resulted in enhanced sodium uptake and loss of the TsHKT1;2 intrinsic K + transporter activity. We consider the maintenance of K + uptake through TsHKT1;2 under salt stress an important component supporting the halophytic lifestyle of T. salsuginea. © 2012 American Society of Plant Biologists
Overexpression of arabidopsis YUCCA6 in potato results in high-auxin developmental phenotypes and enhance
Indole-3-acetic acid (IAA), a major plant auxin, is produced in both tryptophan-dependent and tryptophanindependent pathways. A major pathway in Arabidopsis thaliana generates IAA in two reactions from tryptophan. Step one converts tryptophan to indole-3-pyruvic acid (IPA) by tryptophan aminotransferases followed by a rate-limiting step converting IPA to IAA catalyzed by YUCCA proteins. We identified eight putative StYUC (Solanum tuberosum YUCCA) genes whose deduced amino acid sequences share 50%-70% identity with those of Arabidopsis YUCCA proteins. All include canonical, conserved YUCCA sequences: FATGY motif, FMO signature sequence, and FAD-binding and NADPbinding sequences. In addition, five genes were found with ~50% amino acid sequence identity to Arabidopsis tryptophan aminotransferases. Transgenic potato (Solanum tuberosum cv. Jowon) constitutively overexpressing Arabidopsis AtYUC6 displayed high-auxin phenotypes such as narrow downward-curled leaves, increased height, erect stature, and longevity. Transgenic potato plants overexpressing AtYUC6 showed enhanced drought tolerance based on reduced water loss. The phenotype was correlated with reduced levels of reactive oxygen species in leaves. The results suggest a functional YUCCA pathway of auxin biosynthesis in potato that may be exploited to alter plant responses to the environment. © 2012 The Author
Release of SOS2 kinase from sequestration with GIGANTEA determines salt tolerance in Arabidopsis
Kim, Woe-Yeon et al.--Environmental challenges to plants typically entail retardation of vegetative growth
and delay or cessation of flowering. Here we report a link between the flowering time
regulator, GIGANTEA (GI), and adaptation to salt stress that is mechanistically based
on GI degradation under saline conditions, thus retarding flowering. GI, a switch in
photoperiodicity and circadian clock control, and the SNF1-related protein kinase SOS2
functionally interact. In the absence of stress, the GI:SOS2 complex prevents SOS2-
based activation of SOS1, the major plant Na+/H+-antiporter mediating adaptation to
salinity. GI over-expressing, rapidly flowering, plants show enhanced salt sensitivity,
whereas gi mutants exhibit enhanced salt tolerance and delayed flowering. Salt-induced
degradation of GI confers salt tolerance by the release of the SOS2 kinase. The GISOS2
interaction introduces a higher order regulatory circuit that can explain in
molecular terms, the long observed connection between floral transition and adaptive
environmental stress tolerance in Arabidopsis.This research was supported by the Next-Generation
BioGreen 21 Program (Systems and Synthetic Agrobiotech Center, no. PJ008025), a Cooperative Research Program for Agriculture Science & Technology Development
(Project No. PJ007850), and the Ministry of Education, Science and Technology for the
World Class University (WCU) program (R32-10148) from the Rural Development
Administration, Republic of Korea, and by grant BIO2009-08641 financed by the
Spanish Ministry of Science and Innovation and the FEDER program.Peer reviewe
Diplomirani studenti na Odsjeku za informacijske znanosti Filozofskog fakulteta Sveučilišta u Osijeku za razdoblje 2014.-2016.
<p><b>Copyright information:</b></p><p>Taken from "The SUMO E3 ligase, , regulates flowering by controlling a salicylic acid-mediated floral promotion pathway and through affects on chromatin structure"</p><p></p><p>The Plant Journal 2008;53(3):530-540.</p><p>Published online Jan 2008</p><p>PMCID:PMC2254019.</p><p>© 2007 The Authors Journal compilation 2007 Blackwell Publishing Ltd</p
The F-Box Protein ZEITLUPE Confers Dosage-Dependent Control on the Circadian Clock, Photomorphogenesis, and Flowering Time
As an F-box protein, ZEITLUPE (ZTL) is involved in targeting one or more substrates for ubiquitination and degradation via the proteasome. The initial characterization of ZTL suggested a function limited largely to the regulation of the circadian clock. Here, we show a considerably broader role for ZTL in the control of circadian period and photomorphogenesis. Using a ZTL-specific antibody, we quantitated and characterized a ZTL dosage series that ranges from a null mutation to a strong ZTL overexpressor. In the dark, ztl null mutations lengthen circadian period, and overexpression causes arrhythmicity, suggesting a more comprehensive role for this protein in the clock than previously suspected. In the light, circadian period becomes increasingly shorter at higher levels of ZTL, to the point of arrhythmicity. By contrast, hypocotyl length increases and flowering time is delayed in direct proportion to the level of ZTL. We propose a novel testable mechanism by which circadian period and amplitude may act together to gate phytochrome B–mediated suppression of hypocotyl. We also demonstrate that ZTL-dependent delay of flowering is mediated through decreases in CONSTANS and FLOWERING LOCUS T message levels, thus directly linking proteasome-dependent proteolysis to flowering
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