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Welter S.,CNRS Center of Evolutionary and Functional Ecology | Welter S.,Max Planck Institute for Chemistry | Bracho-Nunez A.,CNRS Center of Evolutionary and Functional Ecology | Bracho-Nunez A.,Max Planck Institute for Chemistry | And 6 more authors.
Tree Physiology | Year: 2012

Interspecific gene flow is common in oaks. In the Mediterranean, this process produced geographical differentiations and new species, which may have contributed to the diversification of the production of volatile terpenes in the oak species of this region. The endemic North African deciduous oak Quercus afares (Pomel) is considered to be a stabilized hybrid between the evergreen Quercus suber (L.) and the deciduous Quercus canariensis (Willd.), presumably being monoterpene and isoprene emitters, respectively. In a common garden experiment, we examined the terpene emission capacities, terpene synthase (TPS) activities and nuclear genetic markers in 52 trees of these three oak species. All but one of the Q. suber and Q. canariensis trees were found to be genetically pure, whereas most Q. afares trees possessed a mixed genotype with a predominance of Q. suber alleles. Analysis of the foliar terpene emissions and TPS activities revealed that all the Q. canariensis trees strongly produced isoprene while all the Q. suber trees were strong monoterpene producers. Quercus afares trees produced monoterpenes as well but at more variable and significantly lower rates, and with a monoterpene pattern different than that observed in Q. suber. Among 17 individuals tested, one Q. afares tree emitted only an insignificant amount of terpenes. No mixed isoprene/monoterpene emitter was detected. Our results suggest that the capacity and pattern of volatile terpene production in Algerian Q. afares populations have strongly diverged from those of its parental species and became quantitatively and qualitatively reduced, including the complete suppression of isoprene production. © 2012 The Author.

Wright L.P.,Max Planck Institute for Chemical Ecology | Rohwer J.M.,Stellenbosch University | Ghirardo A.,Institute of Biochemical Plant Pathology | Hammerbacher A.,Max Planck Institute for Chemical Ecology | And 5 more authors.
Plant Physiology | Year: 2014

The 2-C-methylerythritol 4-phosphate (MEP) pathway supplies precursors for plastidial isoprenoid biosynthesis including carotenoids, redox cofactor side chains, and biogenic volatile organic compounds. We examined the first enzyme of this pathway, 1-deoxyxylulose 5-phosphate synthase (DXS), using metabolic control analysis. Multiple Arabidopsis (Arabidopsis thaliana) lines presenting a range of DXS activities were dynamically labeled with 13CO2 in an illuminated, climate-controlled, gas exchange cuvette. Carbon was rapidly assimilated into MEP pathway intermediates, but not into the mevalonate pathway. A flux control coefficient of 0.82 was calculated for DXS by correlating absolute flux to enzyme activity under photosynthetic steady-state conditions, indicating that DXS is the major controlling enzyme of the MEP pathway. DXS manipulation also revealed a second pool of a downstream metabolite, 2-C- methylerythritol-2,4-cyclodiphosphate (MEcDP), metabolically isolated from the MEP pathway. DXS overexpression led to a 3- to 4-fold increase in MEcDP pool size but to a 2-fold drop in maximal labeling. The existence of this pool was supported by residual MEcDP levels detected in dark-adapted transgenic plants. Both pools of MEcDP are closely modulated by DXS activity, as shown by the fact that the concentration control coefficient of DXS was twice as high for MEcDP (0.74) as for 1-deoxyxylulose 5-phosphate (0.35) or dimethylallyl diphosphate (0.34). Despite the high flux control coefficient for DXS, its overexpression led to only modest increases in isoprenoid end products and in the photosynthetic rate. Diversion of flux via MEcDP may partly explain these findings and suggests new opportunities to engineer the MEP pathway. © 2014 American Society of Plant Biologists. All rights reserved.

Schweier J.,Albert Ludwigs University of Freiburg | Schnitzler J.-P.,Institute of Biochemical Plant Pathology | Becker G.,Albert Ludwigs University of Freiburg
Biomass and Bioenergy | Year: 2016

The use of marginal land for Short Rotation Coppice (SRC) might contribute to a sustainable energy supply in future. We assessed the environmental impacts of common production chains for manufacturing wood chips from SRC with poplar, including all the processes necessary to produce and deliver chips to a plant gate in 50 km distance from the field site ("cradle-to-plant gate"). To do so, we carried out a Life Cycle Analysis (LCA) including upstream processes. Results showed clearly that the specific environmental impacts were mainly caused by the processes "harvesting" and "transport". Using a cut-and-chip harvesting system with a forage harvester generated low impacts during harvesting because of its high productivity. Using a cut-and-storage harvesting system with a whole rod harvester, however, didn't require accompanying tractor-trailer units during harvesting and allowed storing stems before chipping thereby, reducing the moisture content to approximately 30%. Consequently, the transport to the plant caused significantly lower environmental impacts at the same distance (50 km) which lead to a better result when looking at the overall production chain (26 vs. 36 kg CO2-eq Mgdm -1). Respective energy output to energy input ratios were 23:1 and 26:1. We also analysed the impacts of irrigation and fertigation as they might be options to increase biomass yield. Both treatments lead to considerably increased environmental impacts in all analysed categories which might be balanced only if the biomass yields increase substantially; an effect which could not be verified within the current study. © 2015 Elsevier Ltd.

PubMed | Helmholtz Center Munich and University of Aarhus
Type: Journal Article | Journal: Plant, cell & environment | Year: 2016

Nitric oxide (NO) is an important signalling molecule that is involved in many different physiological processes in plants. Here, we report about a NO-fixing mechanism in Arabidopsis, which allows the fixation of atmospheric NO into nitrogen metabolism. We fumigated Arabidopsis plants cultivated in soil or as hydroponic cultures during the whole growing period with up to 3ppmv of NO gas. Transcriptomic, proteomic and metabolomic analyses were used to identify non-symbiotic haemoglobin proteins as key components of the NO-fixing process. Overexpressing non-symbiotic haemoglobin 1 or 2 genes resulted in fourfold higher nitrate levels in these plants compared with NO-treated wild-type. Correspondingly, rosettes size and weight, vegetative shoot thickness and seed yield were 25, 40, 30, and 50% higher, respectively, than in wild-type plants. Fumigation with 250ppbv

Vanzo E.,Helmholtz Center Munich | Merl-Pham J.,Research Unit Protein Science | Velikova V.,Helmholtz Center Munich | Velikova V.,Bulgarian Academy of Science | And 7 more authors.
Plant Physiology | Year: 2016

Researchers have been examining the biological function(s) of isoprene in isoprene-emitting (IE) species for two decades. There is overwhelming evidence that leaf-internal isoprene increases the thermotolerance of plants and protects them against oxidative stress, thus mitigating a wide range of abiotic stresses. However, the mechanisms of abiotic stress mitigation by isoprene are still under debate. Here, we assessed the impact of isoprene on the emission of nitric oxide (NO) and the S-nitroso-proteome of IE and non-isoprene-emitting (NE) gray poplar (Populus × canescens) after acute ozone fumigation. The short-term oxidative stress induced a rapid and strong emission of NO in NE compared with IE genotypes. Whereas IE and NE plants exhibited under nonstressful conditions only slight differences in their S-nitrosylation pattern, the in vivo S-nitroso-proteome of the NE genotype was more susceptible to ozone-induced changes compared with the IE plants. The results suggest that the nitrosative pressure (NO burst) is higher in NE plants, underlining the proposed molecular dialogue between isoprene and the free radical NO. Proteins belonging to the photosynthetic light and dark reactions, the tricarboxylic acid cycle, protein metabolism, and redox regulation exhibited increased S-nitrosylation in NE samples compared with IE plants upon oxidative stress. Because the posttranslational modification of proteins via S-nitrosylation often impacts enzymatic activities, our data suggest that isoprene indirectly regulates the production of reactive oxygen species (ROS) via the control of the S-nitrosylation level of ROS-metabolizing enzymes, thus modulating the extent and velocity at which the ROS and NO signaling molecules are generated within a plant cell. © 2016 American Society of Plant Biologists. All rights reserved.

Velikova V.,Bulgarian Academy of Science | Velikova V.,Institute of Biochemical Plant Pathology | Muller C.,Research Unit Analytical BioGeoChemistry | Ghirardo A.,Institute of Biochemical Plant Pathology | And 5 more authors.
Plant Physiology | Year: 2015

Isoprene is a small lipophilic molecule with important functions in plant protection against abiotic stresses. Here, we studied the lipid composition of thylakoid membranes and chloroplast ultrastructure in isoprene-emitting (IE) and nonisoprene-emitting (NE) poplar (Populus X canescens). We demonstrated that the total amount of monogalactosyldiacylglycerols, digalactosyldiacylglycerols, phospholipids, and fatty acids is reduced in chloroplasts when isoprene biosynthesis is blocked. A significantly lower amount of unsaturated fatty acids, particularly linolenic acid in NE chloroplasts, was associated with the reduced fluidity of thylakoid membranes, which in turn negatively affects photosystem II photochemical efficiency. The low photosystem II photochemical efficiency in NE plants was negatively correlated with nonphotochemical quenching and the energy-dependent component of nonphotochemical quenching. Transmission electron microscopy revealed alterations in the chloroplast ultrastructure in NE compared with IE plants. NE chloroplasts were more rounded and contained fewer grana stacks and longer stroma thylakoids, more plastoglobules, and larger associative zones between chloroplasts and mitochondria. These results strongly support the idea that in IE species, the function of this molecule is closely associated with the structural organization and functioning of plastidic membranes. © 2015 American Society of Plant Biologists. All rights reserved.

Penuelas J.,Global Ecology Unit CREAF CEAB CSIC UAB | Asensio D.,Global Ecology Unit CREAF CEAB CSIC UAB | Tholl D.,Virginia Polytechnic Institute and State University | Wenke K.,University of Rostock | And 3 more authors.
Plant, Cell and Environment | Year: 2014

Volatile compounds are usually associated with an appearance/presence in the atmosphere. Recent advances, however, indicated that the soil is a huge reservoir and source of biogenic volatile organic compounds (bVOCs), which are formed from decomposing litter and dead organic material or are synthesized by underground living organism or organs and tissues of plants. This review summarizes the scarce available data on the exchange of VOCs between soil and atmosphere and the features of the soil and particle structure allowing diffusion of volatiles in the soil, which is the prerequisite for biological VOC-based interactions. In fact, soil may function either as a sink or as a source of bVOCs. Soil VOC emissions to the atmosphere are often 1-2 (0-3) orders of magnitude lower than those from aboveground vegetation. Microorganisms and the plant root system are the major sources for bVOCs. The current methodology to detect belowground volatiles is described as well as the metabolic capabilities resulting in the wealth of microbial and root VOC emissions. Furthermore, VOC profiles are discussed as non-destructive fingerprints for the detection of organisms. In the last chapter, belowground volatile-based bi- and multi-trophic interactions between microorganisms, plants and invertebrates in the soil are discussed. © 2014 John Wiley & Sons Ltd.

Monson R.K.,University of Arizona | Jones R.T.,University of Sydney | Rosenstiel T.N.,Portland State University | Schnitzler J.-P.,Institute of Biochemical Plant Pathology
Plant, Cell and Environment | Year: 2013

Isoprene (2-methyl-1,3-butadiene) is emitted from many plants and it appears to have an adaptive role in protecting leaves from abiotic stress. However, only some species emit isoprene. Isoprene emission has appeared and been lost many times independently during the evolution of plants. As an example, our phylogenetic analysis shows that isoprene emission is likely ancestral within the family Fabaceae (=Leguminosae), but that it has been lost at least 16 times and secondarily gained at least 10 times through independent evolutionary events. Within the division Pteridophyta (ferns), we conservatively estimate that isoprene emissions have been gained five times and lost two times through independent evolutionary events. Within the genus Quercus (oaks), isoprene emissions have been lost from one clade, but replaced by a novel type of light-dependent monoterpene emissions that uses the same metabolic pathways and substrates as isoprene emissions. This novel type of monoterpene emissions has appeared at least twice independently within Quercus, and has been lost from 9% of the individuals within a single population of Quercus suber. Gain and loss of gene function for isoprene synthase is possible through relatively few mutations. Thus, this trait appears frequently in lineages; but, once it appears, the time available for evolutionary radiation into environments that select for the trait is short relative to the time required for mutations capable of producing a non-functional isoprene synthase gene. The high frequency of gains and losses of the trait and its heterogeneous taxonomic distribution in plants may be explained by the relatively few mutations necessary to produce or lose the isoprene synthase gene combined with the assumption that isoprene emission is advantageous in a narrow range of environments and phenotypes. Commentary: Is it useful to ask why plants emit isoprene? Isoprene is a trace gas emitted from many plants and it appears to have an adaptive role in protecting leaves from abiotic stress. However, only some species emit isoprene. Isoprene emission has appeared and been lost many times independently during the evolution of plants. The high frequency of gains and losses of the trait and its heterogeneous taxonomic distribution in plants may be explained by the relatively few mutations necessary to produce or lose the isoprene synthase gene combined with the assumption that isoprene emission is advantageous in a narrow range of environments and phenotypes. © 2012 Blackwell Publishing Ltd.

Huber J.A.,TU Munich | May K.,TU Munich | Siegl T.,Institute of Biochemical Plant Pathology | Schmid H.,TU Munich | And 2 more authors.
Bioenergy Research | Year: 2016

The increasing demand for bioenergy and the combination of agricultural production with conservation has made short-rotation agroforestry systems (SRAFS) a sustainable land-management option. Aboveground woody biomass is a decisive factor in economic and ecological assessment of those systems. To study the yields of organic and conventional SRAFS, the tree species black alder, black locust, poplar clone Max 3, poplar clone Androscoggin, willow clone Inger, and a mixture of different native species were established in an alley-cropping configuration in 2009 and coppiced in 2012. Biomass was determined by harvesting the inner rows of the tree strips and, to investigate row differences within a strip, by an allometric model which estimates tree biomass from stem diameter. Significant variation was observed between species. For inner rows and at the conventional system, highest harvested average annual yield was observed for poplar Androscoggin (10.5 todt ha−1 year−1), followed by black locust (9.7 todt ha−1 year−1), poplar Max 3 (8.6 todt ha−1 year−1), black alder (7.6 todt ha−1 year−1), the native mix (4.9 todt ha−1 year−1), and willow (3.9 todt ha−1 year−1). At the organic system, highest yields were observed for poplar Max 3 (Androscoggin not planted) (10.9 todt ha−1 year−1), followed by black locust (8.1 todt ha−1 year−1), black alder (7.4 todt ha−1 year−1), willow (6.4 todt ha−1 year−1), and the native mix (4.7 todt ha−1 year−1). Farming system differences were only significant for willow and poplar Max 3; however, the higher yields of the organic system seemed to be a result of varying small-scale site properties rather than a management effect. Border rows showed 18–111 % more yield than inner rows because of greater tree diameters or heights and higher number of stems. This edge effect was emphasized in the conventional systems, possibly indicating that trees benefit from fertilizers applied at adjacent crop fields. © 2016 Springer Science+Business Media New York

PubMed | Institute of Biochemical Plant Pathology
Type: Journal Article | Journal: Journal of proteomics | Year: 2011

Proteome analyses suffer from the large complexity of even small proteomes. Additionally, in many protein samples a few highly abundant proteins are hindering detailed proteomic studies, since they mask low abundant proteins. Recently, a new technology has emerged, which reduces dynamic range of protein concentrations within a given sample using combinatorial hexapeptide ligand libraries (CPLLs). This technique has been widely used in the microbial, animal and human fields and is now going to enter plant research. It can be a useful tool for fractionation of protein samples and might help to get a deeper insight into specific plant proteomes. In this review we describe the CPLL protein fractionation, summarize its possible applications in the plant field and discuss the limitations of this method.

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