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Frederiksberg, Denmark

Park J.,Pohang University of Science and Technology | Song W.-Y.,Pohang University of Science and Technology | Ko D.,Pohang University of Science and Technology | Eom Y.,Yonsei University | And 6 more authors.
Plant Journal | Year: 2012

Summary Heavy metals such as cadmium (Cd) and mercury (Hg) are toxic pollutants that are detrimental to living organisms. Plants employ a two-step mechanism to detoxify toxic ions. First, phytochelatins bind to the toxic ion, and then the metal-phytochelatin complex is sequestered in the vacuole. Two ABCC-type transporters, AtABCC1 and AtABCC2, that play a key role in arsenic detoxification, have recently been identified in Arabidopsis thaliana. However, it is unclear whether these transporters are also implicated in phytochelatin-dependent detoxification of other heavy metals such as Cd(II) and Hg(II). Here, we show that atabcc1 single or atabcc1 atabcc2 double knockout mutants exhibit a hypersensitive phenotype in the presence of Cd(II) and Hg(II). Microscopic analysis using a Cd-sensitive probe revealed that Cd is mostly located in the cytosol of protoplasts of the double mutant, whereas it occurs mainly in the vacuole of wild-type cells. This suggests that the two ABCC transporters are important for vacuolar sequestration of Cd. Heterologous expression of the transporters in Saccharomyces cerevisiae confirmed their role in heavy metal tolerance. Over-expression of AtABCC1 in Arabidopsis resulted in enhanced Cd(II) tolerance and accumulation. Together, these results demonstrate that AtABCC1 and AtABCC2 are important vacuolar transporters that confer tolerance to cadmium and mercury, in addition to their role in arsenic detoxification. These transporters provide useful tools for genetic engineering of plants with enhanced metal tolerance and accumulation, which are desirable characteristics for phytoremediation. © 2011 The Authors. Source

Bruun S.,Plant and Soil Science Laboratory | Jensen J.W.,Plant and Soil Science Laboratory | Magid J.,Plant and Soil Science Laboratory | Lindedam J.,Plant and Soil Science Laboratory | Engelsen S.B.,Quality and Technology
Industrial Crops and Products | Year: 2010

Degradability of straw is important in connection with the fermentation process for bioethanol production, while the ash content is important for its suitability for incineration. Therefore, a fast method for assessment of straw quality could be very useful in determining the price and in helping choose between different applications for specific straw batches, such as fermentation for ethanol production, incineration or animal feed. This study investigated the ability of near infrared (NIR) spectroscopy to predict the degradability and ash content of 106 cultivars of wheat straw grown at two different sites. In general, calibrations based on NIR spectra recorded on air-dried samples performed better than those on oven-dried samples. A partial least squares (PLS) calibration based on the spectra of the air-dried samples predicted degradability with r2 = 0.72 and RMSECV = 1.4% with 3 components using samples from the two different sites. The ash content was well predicted with r2 = 0.99 and RMSECV = 0.195% using a complex 15-component PLS model validated using repeated random segmented cross-validation. However, this model proved to be sensitive to site in a validation using the two sites as segments, where the accuracy of ash content prediction decreased to r2 = 0.91 and RMSECV = 0.691% using a 9-component PLS model. NIR spectroscopy proved useful for predicting degradability and ash content of wheat straw from different wheat cultivars. However, when developing predictive models of ash content based on NIR spectra, it should be ensured that the models are transferable to locations other than those used for model calibration. © 2009 Elsevier B.V. All rights reserved. Source

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