ALBERT

Description:    The use of artificial freezing tests, identification of biomarkers linked to or directly involved in the low-temperature tolerance processes, could prove useful in applied strawberry breeding. This study was conducted to identify genotypes of diploid strawberry that differ in their tolerance to low-temperature stress and to investigate whether a set of candidate proteins and metabolites correlate with the level of tolerance. 17 Fragaria vesca , 2 F. nilgerrensis , 2 F. nubicola , and 1 F. pentaphylla genotypes were evaluated for low-temperature tolerance. Estimates of temperatures where 50 % of the plants survived (LT 50 ) ranged from −4.7 to −12.0 °C between the genotypes. Among the F. vesca genotypes, the LT 50 varied from −7.7 °C to −12.0 °C. Among the most tolerant were three F. vesca ssp. bracteata genotypes (FDP821, NCGR424, and NCGR502), while a F. vesca ssp. californica genotype (FDP817) was the least tolerant (LT 50 −7.7 °C). Alcohol dehydrogenase (ADH), total dehydrin expression, and content of central metabolism constituents were assayed in select plants acclimated at 2 °C. The LT 50 estimates and the expression of ADH and total dehydrins were highly correlated ( r adh  = −0.87, r dehyd  = −0.82). Compounds related to the citric acid cycle were quantified in the leaves during acclimation. While several sugars and acids were significantly correlated to the LT 50 estimates early in the acclimation period, only galactinol proved to be a good LT 50 predictor after 28 days of acclimation ( r galact  = 0.79). It is concluded that ADH, dehydrins, and galactinol show great potential to serve as biomarkers for cold tolerance in diploid strawberry. Content Type Journal Article Category Original Article Pages 1-13 DOI 10.1007/s00425-012-1771-2 Authors Jahn Davik, Bioforsk - Norwegian Institute for Agricultural and Environmental Research, Kvithamar, 7500 Stjordal, Norway Gage Koehler, Department of Biology, Indiana University Purdue University Indianapolis, Indiana, 46202 USA Britta From, Department of Natural Sciences and Technology, Hedmark University College, 2318 Hamar, Norway Torfinn Torp, Bioforsk - Norwegian Institute for Agricultural and Environmental Research, 1432 Ås, Norway Jens Rohloff, Department of Biology, Norwegian University of Science and Technology, 7491 Trondheim, Norway Petter Eidem, Department of Biology, Norwegian University of Science and Technology, 7491 Trondheim, Norway Robert C. Wilson, Department of Natural Sciences and Technology, Hedmark University College, 2318 Hamar, Norway Anita Sønsteby, Bioforsk - Norwegian Institute for Agricultural and Environmental Research, 2849 Kapp, Norway Stephen K. Randall, Department of Biology, Indiana University Purdue University Indianapolis, Indiana, 46202 USA Muath Alsheikh, Graminor Breeding Ltd., 2322 Ridabu, Norway Journal Planta Online ISSN 1432-2048 Print ISSN 0032-0935

Description:    Lipopolysaccharides (LPS), as lipoglycan microbe-associated molecular pattern molecules, trigger activation of signal transduction pathways involved in defence that generate an enhanced defensive capacity in plants. The transcriptional regulation of the genes for tryptophan synthase B, TSB1 , and the cytochrome P450 monooxygenases CYP79B2 and CYP71B15 , involved in the camalexin biosynthetic pathway, were investigated in response to LPS treatment. GUS-reporter assays for CYP71B15 and CYP79B2 gene promoter activation were performed on transgenic plants and showed positive histochemical staining in response to LPS treatment, indicating activation of the promoters. Quantitative PCR revealed that transcripts of TSB1 , CYP79B2 and CYP71B15 exhibited differential, transient up-regulation. TSB1 transcript levels were up-regulated between 6 and 9 h after LPS-induction, while CYP71B15 and CYP79B2 both exhibited maxima at 12 h. To obtain information on the gene-to-metabolite network, the effect of the transcriptome changes on the metabolome was correlated to camalexin production. Increases in camalexin concentration were quantified by ultra pressure liquid chromatography-mass spectrometry and both absorbance spectra and elemental composition confirmed its identity. The concentrations increased from 0.03 to 3.7 μg g −1 fresh weight over a 24-h time period, thus indicating that the up-regulation of the biosynthetic pathway in response to LPS was accompanied by a time-dependent increase in camalexin concentration. Metabolomic analysis through principal component analysis-derived scores plots revealed clusters of sample replicates for 0, 6, 12, 18 and 24 h while loadings plots for LPS data identified camalexin as a biomarker that clearly demonstrated the variability between samples. Content Type Journal Article Category Original Article Pages 1-12 DOI 10.1007/s00425-012-1606-1 Authors Caryn Ann Beets, Department of Biochemistry, University of Johannesburg, Auckland Park, Johannesburg, South Africa Ju-Chi Huang, Department of Biochemistry, University of Johannesburg, Auckland Park, Johannesburg, South Africa Ntakadzeni Edwin Madala, Department of Biochemistry, University of Johannesburg, Auckland Park, Johannesburg, South Africa Ian Dubery, Department of Biochemistry, University of Johannesburg, Auckland Park, Johannesburg, South Africa Journal Planta Online ISSN 1432-2048 Print ISSN 0032-0935

Description:    The nucleolar activity of Hyacinthus orientalis L. embryo sac cells was investigated. The distributions of nascent pre-rRNA (ITS1), 26S rRNA and of the 5S rRNA and U3 snoRNA were determined using fluorescence in situ hybridization (FISH). Our results indicated the different rRNA metabolism of the H. orientalis female gametophyte cells before and after fertilization. In the target cells for the male gamete, i.e., the egg cell and the central cell whose activity is silenced in the mature embryo sac (Pięciński et al. in Sex Plant Reprod 21:247–257, 2008 ; Niedojadło et al. in Planta doi: 10.1007/s00425-012-1599-9 , 2011 ), rRNA metabolism is directed at the accumulation of rRNPs in the cytoplasm and immature transcripts in the nucleolus. In both cells, fertilization initiates the maturation of the maternal pre-rRNA and the expression of zygotic rDNA. The resumption of rRNA transcription observed in the hyacinth zygote indicates that in plants, there is a different mechanism for the regulation of RNA Pol I activity than in animals. In synergids and antipodal cells, which have somatic functions, the nucleolar activity is correlated with the metabolic activity of these cells and changes in successive stages of embryo sac development. Content Type Journal Article Category Original Article Pages 1-14 DOI 10.1007/s00425-012-1618-x Authors Katarzyna Niedojadło, Department of Cell Biology, Institute of General and Molecular Biology, Nicolaus Copernicus University, Gagarina 9, 87-100 Toruń, Poland Szymon Pięciński, Department of Cell Biology, Institute of General and Molecular Biology, Nicolaus Copernicus University, Gagarina 9, 87-100 Toruń, Poland Dariusz Jan Smoliński, Department of Cell Biology, Institute of General and Molecular Biology, Nicolaus Copernicus University, Gagarina 9, 87-100 Toruń, Poland Elżbieta Bednarska-Kozakiewicz, Department of Cell Biology, Institute of General and Molecular Biology, Nicolaus Copernicus University, Gagarina 9, 87-100 Toruń, Poland Journal Planta Online ISSN 1432-2048 Print ISSN 0032-0935

Description:    Acylamino acid-releasing enzyme/oxidized protein hydrolase (AARE/OPH) has been biochemically demonstrated to be a bifunctional protease that has exopeptidase activity against N α -acylated peptides and endopeptidase activity against oxidized and glycated proteins; however, its physiological role remains unknown. In this study, to determine its physiological significance, we produced AARE/OPH-overexpressing and -suppressed plants and assessed the biological impacts of AARE/OPH. The subcellular localization of Arabidopsis AARE/OPH was found to be cytoplasmic and nuclear by transient expression analysis of tdTomato-fused Arabidopsis AARE/OPH. Overexpression of AARE/OPH exhibited no apparent effect on the level of oxidized proteins because wild types probably have inherently high AARE/OPH activity. Through RNAi gene suppressing, we successfully produced AARE/OPH-suppressed Arabidopsis plants ( aare ) that exhibited almost no AARE activity. In the aare plant, electrolyte leakage by methyl viologen treatment was enhanced compared to that of non-transformant plants, suggesting that the plasma membranes of aare easily suffered oxidative damage, probably as a result of deterioration of the cytoplasmic antioxidative system. Correspondingly, proteomic analysis revealed that the aare plant accumulated a number of oxidized proteins including cytoplasmic antioxidant enzymes. On the basis of these results, we concluded that AARE/OPH plays a homeostatic role in sustaining the cytoplasmic antioxidative system. Content Type Journal Article Category Original Article Pages 1-10 DOI 10.1007/s00425-012-1614-1 Authors Atsushi Nakai, Faculty of Agriculture, Tottori University, Koyama-cho Minami 4-101, Tottori, 680-8553 Japan Yasuo Yamauchi, Graduate School of Agricultural Science, Kobe University, Rokkodai 1-1, Kobe, 657-8501 Japan Sawako Sumi, Faculty of Agriculture, Tottori University, Koyama-cho Minami 4-101, Tottori, 680-8553 Japan Kiyoshi Tanaka, Faculty of Agriculture, Tottori University, Koyama-cho Minami 4-101, Tottori, 680-8553 Japan Journal Planta Online ISSN 1432-2048 Print ISSN 0032-0935

Description:    Tryptophan decarboxylase (TDC) converts tryptophan into tryptamine that is the indole moiety of ajmalicine. The full-length cDNA of Rauvolfia verticillata ( RvTDC ) was 1,772 bps that contained a 1,500-bp ORF encoding a 499-amino-acid polypeptide. Recombinant 55.5 kDa RvTDC converted tryptophan into tryptamine. The K m of RvTDC for tryptophan was 2.89 mM, higher than those reported in other TIAs-producing plants. It demonstrated that RvTDC had lower affinity to tryptophan than other plant TDCs. The K m of RvTDC was also much higher than that of strictosidine synthase and strictosidine glucosidase in Rauvolfia . This suggested that TDC might be the committed-step enzyme involved in ajmalicine biosynthesis in R . verticillata . The expression of RvTDC was slightly upregulated by MeJA; the five MEP pathway genes and SGD showed no positive response to MeJA; and STR was sharply downregulated by MeJA. MeJA-treated hairy roots produced higher level of ajmalicine (0.270 mg g −1 DW) than the EtOH control (0.183 mg g −1 DW). Highest RvTDC expression level was detected in hairy root, about respectively 11, 19, 65, and 109-fold higher than in bark, young leaf, old leaf, and root. Highest ajmalicine content was also found in hairy root (0.249 mg g −1 DW) followed by in bark (0.161 mg g −1 DW) and young leaf (0.130 mg g −1 DW), and least in root (0.014 mg g −1 DW). Generally, the expression level of RvTDC was positively consistent with the accumulation of ajmalicine. Therefore, it could be deduced that TDC might be the key enzyme involved in ajmalicine biosynthesis in Rauvolfia . Content Type Journal Article Category Original Article Pages 1-12 DOI 10.1007/s00425-012-1608-z Authors Wanhong Liu, Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), Laboratory of Natural Products and Metabolic Engineering, Chongqing Engineering and Technology Research Center for Sweetpotato, School of Life Sciences, Southwest University, Chongqing, 400715 China Rong Chen, Center for Biomedicine and Health, Hangzhou Normal University, Hangzhou, 310012 China Min Chen, School of Pharmaceutical Sciences, Southwest University, Chongqing, 400715 China Haoxing Zhang, Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), Laboratory of Natural Products and Metabolic Engineering, Chongqing Engineering and Technology Research Center for Sweetpotato, School of Life Sciences, Southwest University, Chongqing, 400715 China Meifang Peng, Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), Laboratory of Natural Products and Metabolic Engineering, Chongqing Engineering and Technology Research Center for Sweetpotato, School of Life Sciences, Southwest University, Chongqing, 400715 China Chunxian Yang, Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), Laboratory of Natural Products and Metabolic Engineering, Chongqing Engineering and Technology Research Center for Sweetpotato, School of Life Sciences, Southwest University, Chongqing, 400715 China Xingjia Ming, Chongqing Academy of Chinese Materia Medica, Chongqing, 400065 China Xiaozhong Lan, Tibet Agricultural and Animal Husbandry College, Nyingchi of Tibet, 860000 China Zhihua Liao, School of Life Sciences, Southwest University, Chongqing, 400715 China Journal Planta Online ISSN 1432-2048 Print ISSN 0032-0935

Description:    Reports about diurnal changes of assimilates in phloem sap are controversial. We determined the diurnal changes of sucrose and amino acid concentrations and fluxes in exudates from cut aphid stylets on tansy leaves ( Tanacetum vulgare ), and sucrose, amino acid and K + concentrations and fluxes in bleeding sap of castor bean pedicel ( Ricinus communis ). Approximately half of the tansy sieve tubes exhibited a diurnal cycle of sucrose concentrations and fluxes in phloem sap. Data from many tansy plants indicated an increased sucrose flux in the phloem during daytime in case of low N-nutrition, not at high N-nutrition. The sucrose concentration in phloem sap of young Ricinus plants changed marginally between day and night, whereas the sucrose flux increased 1.5-fold during daytime (but not in old Ricinus plants). The amino acid concentrations and fluxes in tansy sieve tubes exhibited a similar diurnal cycle as the sucrose concentrations and fluxes, including their dependence on N-nutrition. The amino acid fluxes, but not the concentrations, in phloem sap of Ricinus were higher at daytime. The sucrose/amino acid ratio showed no diurnal cycle neither in tansy nor in Ricinus . The K + -concentrations in phloem sap of Ricinus , but not the K + fluxes, decreased slightly during daytime and the sucrose/K + -ratio increased. In conclusion, a diurnal cycle was observed in sucrose, amino acid and K + fluxes, but not necessarily in concentrations of these assimilates. Because of the large variations between different sieve tubes and different plants, the nutrient delivery to sink tissues is not homeostatic over time. Content Type Journal Article Category Original Article Pages 1-15 DOI 10.1007/s00425-012-1600-7 Authors Jose Kallarackal, Pflanzenphysiologie, Universität Bayreuth, 95440 Bayreuth, Germany Susanne N. Bauer, Pflanzenphysiologie, Universität Bayreuth, 95440 Bayreuth, Germany Heike Nowak, Pflanzenphysiologie, Universität Bayreuth, 95440 Bayreuth, Germany Mohammad-Reza Hajirezaei, Physiologie und Zellbiologie, Leibnitz Institut IPK, 06466 Gatersleben, Germany Ewald Komor, Pflanzenphysiologie, Universität Bayreuth, 95440 Bayreuth, Germany Journal Planta Online ISSN 1432-2048 Print ISSN 0032-0935

Description:    Salinity stress is one of the most common abiotic stresses that hamper plant productivity worldwide. Successful plant adaptations to salt stress require substantial changes in cellular protein expression. In this work, we present a 2-DE-based proteomic analysis of a model unicellular green alga, Chlamydomonas reinhardtii , subjected to 300 mM NaCl for 2 h. Results showed that, in addition to the protein spots that showed partial up- or down-regulation patterns, a number of proteins were exclusively present in the proteome of the control cells, but were absent from the salinity-stressed samples. Conversely, a large number of proteins exclusively appeared in the proteome of the salinity-stressed samples. Of those exclusive proteins, we could successfully identify, via LC–MS/MS, 18 spots uniquely present in the control cells and 99 spots specific to NaCl-treated cells. Interestingly, among the salt-exclusive protein spots, we identified several important housekeeping proteins like molecular chaperones and proteins of the translation machinery, suggesting that they may originate from post-translational modifications rather than from de novo biosynthesis. The possible role and the salt-specific modification of these proteins by salinity stress are discussed. Content Type Journal Article Category Rapid Communication Pages 1-11 DOI 10.1007/s00425-012-1594-1 Authors Chotika Yokthongwattana, Department of Biochemistry, Faculty of Science, Kasetsart University, 50 Phahonyothin Rd., Bangkok, 10900 Thailand Bancha Mahong, Department of Biochemistry, Center for Excellence in Protein Structure and Function, Faculty of Science, Mahidol University, 272 Rama 6 Rd., Bangkok, 10400 Thailand Sittiruk Roytrakul, Genome Institute, National Center for Genetic Engineering and Biotechnology, 113 Thailand Science Park, Phahonyothin Rd., Pathumthani, 12120 Thailand Narumon Phaonaklop, Genome Institute, National Center for Genetic Engineering and Biotechnology, 113 Thailand Science Park, Phahonyothin Rd., Pathumthani, 12120 Thailand Jarunya Narangajavana, Department of Biotechnology, Faculty of Science, Mahidol University, 272 Rama 6 Rd., Bangkok, 10400 Thailand Kittisak Yokthongwattana, Department of Biochemistry, Center for Excellence in Protein Structure and Function, Faculty of Science, Mahidol University, 272 Rama 6 Rd., Bangkok, 10400 Thailand Journal Planta Online ISSN 1432-2048 Print ISSN 0032-0935

Description:    High-throughput RNA sequencing was performed for comprehensively analyzing the transcriptome of the purple sweet potato. A total of 58,800 unigenes were obtained and ranged from 200 nt to 10,380 nt with an average length of 476 nt. The average expression of one unigene was 34 reads per kb per million reads (RPKM) with a maximum expression of 1,935 RPKM. At least 40,280 (68.5%) unigenes were identified to be protein-coding genes, in which 11,978 and 5,184 genes were homologous to Arabidopsis and rice proteins, respectively. Gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) analysis showed that 19,707 (33.5%) unigenes were classified to 1,807 terms of GO including molecular functions, biological processes, and cellular components and 9,970 (17.0%) unigenes were enriched to 11,119 KEGG pathways. We found that at least 3,553 genes may be involved in the biosynthesis pathways of starch, alkaloids, anthocyanin pigments, and vitamins. Additionally, 851 potential simple sequence repeats (SSRs) were identified in all unigenes. Transcriptome sequencing on tuberous roots of the sweet potato yielded substantial transcriptional sequences and potentially useful SSR markers which provide an important data source for sweet potato research. Comparison of two RNA-sequence datasets from the purple and the yellow sweet potato showed that UDP-glucose-flavonoid 3- O -glucosyltransferase was one of the key enzymes in the pathway of anthocyanin biosynthesis and that anthocyanin-3-glucoside might be one of the major components for anthocyanin pigments in the purple sweet potato. This study contributes to the molecular mechanisms of sweet potato development and metabolism and therefore that increases the potential utilization of the sweet potato in food nutrition and pharmacy. Content Type Journal Article Category Original Article Pages 1-13 DOI 10.1007/s00425-012-1591-4 Authors Fuliang Xie, Department of Biology, East Carolina University, Greenville, NC 27858, USA Caitlin E. Burklew, Department of Biology, East Carolina University, Greenville, NC 27858, USA Yanfang Yang, The Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091 China Min Liu, College of Plant Science, Agriculture University of Beijing, Beijing, 102206 China Peng Xiao, Department of Mathematics, East Carolina University, Greenville, NC 27858, USA Baohong Zhang, Department of Biology, East Carolina University, Greenville, NC 27858, USA Deyou Qiu, The Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091 China Journal Planta Online ISSN 1432-2048 Print ISSN 0032-0935

Description:    Sorting of transmembrane proteins into the inner vesicles of multivesicular bodies for subsequent delivery to the vacuole/lysosome can be induced by attachment of a single ubiquitin or K63-linked ubiquitin chains to the cytosolic portion of the cargo in yeast and mammals. In plants, large efforts have been undertaken to elucidate the mechanisms of vacuolar trafficking of soluble proteins. Sorting of transmembrane proteins, by contrast, is still largely unexplored. As a proof of principle, that ubiquitin is involved in vacuolar sorting in plants we show that a translational fusion of a single ubiquitin to the Arabidopsis plasma membrane ATPase PMA-EGFP is sufficient to induce its endocytosis and sorting into the vacuolar lumen. Sorting of the artificial reporter is not dependent on ubiquitin chain formation, but involves ubiquitin’s hydrophobic patch and can be inhibited by coexpression of a dominant-negative version of the ESCRT (endosomal sorting complex required for transport) related protein AtSKD1 (SUPPRESSOR OF K+ TRANSPORT GROWTH DEFECT1). Our results suggest that ubiquitin can in principle act as vacuolar sorting signal in plants. Content Type Journal Article Category Original Article Pages 1-15 DOI 10.1007/s00425-012-1587-0 Authors Stefanie Herberth, Botanical Institute III, Biocenter, University of Cologne, Zülpicher Str. 47b, 50674 Cologne, Germany Mojgan Shahriari, Botanical Institute III, Biocenter, University of Cologne, Zülpicher Str. 47b, 50674 Cologne, Germany Michael Bruderek, Botanical Institute III, Biocenter, University of Cologne, Zülpicher Str. 47b, 50674 Cologne, Germany Florian Hessner, Botanical Institute III, Biocenter, University of Cologne, Zülpicher Str. 47b, 50674 Cologne, Germany Britta Müller, Botanical Institute III, Biocenter, University of Cologne, Zülpicher Str. 47b, 50674 Cologne, Germany Martin Hülskamp, Botanical Institute III, Biocenter, University of Cologne, Zülpicher Str. 47b, 50674 Cologne, Germany Swen Schellmann, Botanical Institute III, Biocenter, University of Cologne, Zülpicher Str. 47b, 50674 Cologne, Germany Journal Planta Online ISSN 1432-2048 Print ISSN 0032-0935

Description:    Arabidopsis caffeoyl coenzyme A dependent O -methyltransferase 1 (CCoAOMT1) and caffeic acid O -methyltransferase 1 (COMT1) display a similar substrate profile although with distinct substrate preferences and are considered the key methyltransferases (OMTs) in the biosynthesis of lignin monomers, coniferyl and sinapoylalcohol. Whereas CCoAOMT1 displays a strong preference for caffeoyl coenzyme A, COMT1 preferentially methylates 5-hydroxyferuloyl CoA derivatives and also performs methylation of flavonols with vicinal aromatic dihydroxy groups, such as quercetin. Based on different knockout lines, phenolic profiling, and immunohistochemistry, we present evidence that both enzymes fulfil distinct, yet different tasks in Arabidopsis anthers. CCoAOMT1 besides its role in vascular tissues can be localized to the tapetum of young stamens, contributing to the biosynthesis of spermidine phenylpropanoid conjugates. COMT1, although present in the same organ, is not localized in the tapetum, but in two directly adjacent cells layers, the endothecium and the epidermal layer of stamens. In vivo localization and phenolic profiling of comt1 plants provide evidence that COMT1 neither contributes to the accumulation of spermidine phenylpropanoid conjugates nor to the flavonol glycoside pattern of pollen grains. Content Type Journal Article Category Original Article Pages 1-11 DOI 10.1007/s00425-011-1586-6 Authors Christin Fellenberg, Department of Cell and Metabolic Biology, Leibniz Institute of Plant Biochemistry, Weinberg 3, 06120 Halle (Saale), Germany Maike van Ohlen, Department of Cell and Metabolic Biology, Leibniz Institute of Plant Biochemistry, Weinberg 3, 06120 Halle (Saale), Germany Vinzenz Handrick, Department of Cell and Metabolic Biology, Leibniz Institute of Plant Biochemistry, Weinberg 3, 06120 Halle (Saale), Germany Thomas Vogt, Department of Cell and Metabolic Biology, Leibniz Institute of Plant Biochemistry, Weinberg 3, 06120 Halle (Saale), Germany Journal Planta Online ISSN 1432-2048 Print ISSN 0032-0935