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Tree Physiol

Title:		Isoprene function in two contrasting poplars under salt and sunflecks
Author(s):		Behnke K; Ghirardo A; Janz D; Kanawati B; Esperschutz J; Zimmer I; Schmitt-Kopplin P; Niinemets U; Polle A; Schnitzler JP; Rosenkranz M;
Address:		"Research Unit Environmental Simulation, Institute of Biochemical Plant Pathology, Helmholtz Zentrum Munchen, 85764 Neuherberg, Germany"
Journal Title:		Tree Physiol
Year:		2013
Volume:		20130326
Issue:		6
Page Number:		562 - 578
DOI:		10.1093/treephys/tpt018
ISSN/ISBN:		1758-4469 (Electronic) 0829-318X (Linking)
Abstract:		"In the present study, biogenic volatile organic compound (BVOC) emissions and photosynthetic gas exchange of salt-sensitive (Populus x canescens (Aiton) Sm.) and salt-tolerant (Populus euphratica Oliv.) isoprene-emitting and non-isoprene-emitting poplars were examined under controlled high-salinity and high-temperature and -light episode ('sunfleck') treatments. Combined treatment with salt and sunflecks led to an increased isoprene emission capacity in both poplar species, although the photosynthetic performance of P. x canescens was reduced. Indeed, different allocations of isoprene precursors between the cytosol and the chloroplast in the two species were uncovered by means of (13)CO2 labeling. Populus x canescens leaves, moreover, increased their use of 'alternative' carbon (C) sources in comparison with recently fixed C for isoprene biosynthesis under salinity. Our studies show, however, that isoprene itself does not have a function in poplar survival under salt stress: the non-isoprene-emitting leaves showed only a slightly decreased photosynthetic performance compared with wild type under salt treatment. Lipid composition analysis revealed differences in the double bond index between the isoprene-emitting and non-isoprene-emitting poplars. Four clear metabolomics patterns were recognized, reflecting systemic changes in flavonoids, sterols and C fixation metabolites due to the lack/presence of isoprene and the absence/presence of salt stress. The studies were complemented by long-term temperature stress experiments, which revealed the thermotolerance role of isoprene as the non-isoprene-emitting leaves collapsed under high temperature, releasing a burst of BVOCs. Engineered plants with a low isoprene emission potential might therefore not be capable of resisting high-temperature episodes"
Keywords:		Butadienes/metabolism Carbon/*metabolism Carbon Dioxide/metabolism Flavonoids/genetics/metabolism Hemiterpenes/biosynthesis/*genetics/metabolism *Hot Temperature Metabolome/genetics Pentanes/metabolism Photosynthesis/genetics Phytosterols/genetics/metabol;
Notes:		"MedlineBehnke, K Ghirardo, A Janz, D Kanawati, B Esperschutz, J Zimmer, I Schmitt-Kopplin, P Niinemets, U Polle, A Schnitzler, J P Rosenkranz, M eng Research Support, Non-U.S. Gov't Canada 2013/03/28 Tree Physiol. 2013 Jun; 33(6):562-78. doi: 10.1093/treephys/tpt018. Epub 2013 Mar 26"