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Meyer R.C.,Leibniz Institute of Plant Genetics and Crop Plant Research | Witucka-Wall H.,University of Potsdam | Witucka-Wall H.,Parexel International | Becher M.,University of Potsdam | And 22 more authors.
Plant Journal | Year: 2012

Heterosis-associated cellular and molecular processes were analyzed in seeds and seedlings of Arabidopsis thaliana accessions Col-0 and C24 and their heterotic hybrids. Microscopic examination revealed no advantages in terms of hybrid mature embryo organ sizes or cell numbers. Increased cotyledon sizes were detectable 4 days after sowing. Growth heterosis results from elevated cell sizes and numbers, and is well established at 10 days after sowing. The relative growth rates of hybrid seedlings were most enhanced between 3 and 4 days after sowing. Global metabolite profiling and targeted fatty acid analysis revealed maternal inheritance patterns for a large proportion of metabolites in the very early stages. During developmental progression, the distribution shifts to dominant, intermediate and heterotic patterns, with most changes occurring between 4 and 6 days after sowing. The highest incidence of heterotic patterns coincides with establishment of size differences at 4 days after sowing. In contrast, overall transcript patterns at 4, 6 and 10 days after sowing are characterized by intermediate to dominant patterns, with parental transcript levels showing the largest differences. Overall, the results suggest that, during early developmental stages, intermediate gene expression and higher metabolic activity in the hybrids compared to the parents lead to better resource efficiency, and therefore enhanced performance in the hybrids. © 2012 The Authors. The Plant Journal © 2012 Blackwell Publishing Ltd.

Armbruster U.,Ludwig Maximilians University of Munich | Ruhle T.,Ludwig Maximilians University of Munich | Kreller R.,Ludwig Maximilians University of Munich | Strotbek C.,Ludwig Maximilians University of Munich | And 11 more authors.
Plant Cell | Year: 2013

In vascular plants, the chloroplast NAD(P)H dehydrogenase complex (NDH-C) is assembled from five distinct subcomplexes, the membrane-spanning (subM) and the luminal (subL) subcomplexes, as well as subA, subB, and subE. The assembly process itself is poorly understood. Vascular plant genomes code for two related intrinsic thylakoid proteins, PHOTOSYNTHESIS-AFFECTED MUTANT68 (PAM68), a photosystem II assembly factor, and PHOTOSYNTHESIS-AFFECTED MUTANT68-LIKE (PAM68L). As we show here, inactivation of Arabidopsis thaliana PAM68L in the pam68l-1 mutant identifies PAM68L as an NDH-C assembly factor. The mutant lacks functional NDH holocomplexes and accumulates three distinct NDH-C assembly intermediates (subB, subM, and subA+L), which are also found in mutants defective in subB assembly (ndf5) or subM expression (CHLORORESPIRATORY REDUCTION4-3 mutant). NDH-C assembly in the cyanobacterium Synechocystis sp PCC 6803 and the moss Physcomitrella patens does not require PAM68 proteins, as demonstrated by the analysis of knockout lines for the single-copy PAM68 genes in these species. We conclude that PAM68L mediates the attachment of subB- and subM-containing intermediates to a complex that contains subA and subL. The evolutionary appearance of subL and PAM68L during the transition from mosses like P. patens to flowering plants suggests that the associated increase in the complexity of the NDH-C might have been facilitated by the recruitment of evolutionarily novel assembly factors like PAM68L. © 2013 American Society of Plant Biologists. All rights reserved.

Franceschi P.,Edmund Machinery Foundation Research and Innovation Center | Masuero D.,Edmund Machinery Foundation Research and Innovation Center | Vrhovsek U.,Edmund Machinery Foundation Research and Innovation Center | Mattivi F.,Edmund Machinery Foundation Research and Innovation Center | Wehrens R.,Edmund Machinery Foundation Research and Innovation Center
Journal of Chemometrics | Year: 2012

The development and the validation of innovative approaches for biomarker selection are of paramount importance in many -omics technologies. Unfortunately, the actual testing of new methods on real data is difficult, because in real data sets, one can never be sure about the "true" biomarkers. In this paper, we present a publicly available metabolomic ultra performance liquid chromatography-mass spectrometry spike-in data set for apples. The data set consists of 10 control samples and three spiked sets of the same size, where naturally occurring compounds are added in different concentrations. In this sense, the data set can serve as a test bed to assess the performance of new algorithms and compare them with previously published results. We illustrate some of the possibilities provided by this spike-in data set by comparing the performance of two popular biomarker-selection methods, the univariate t-test and the multivariate variable importance in projection. To promote a widespread use of the data, raw data files as well as preprocessed peak lists are made available. © 2012 John Wiley & Sons, Ltd.

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