High Productivity in Hybrid-poplar Plantations Without Isoprene Emission to the Atmosphere
R.K.M. acknowledges financial support from the Macrosystems Program in the Emerging Frontiers Section of the NSF (Award 1065790), the Ecosystems Program in the Division of Environmental Biology (NSF Award 1754430), and the Water, Environmental, and Energy Solutions program supported by the Technology and Research Initiative Fund from the State of Arizona. J.-P.S. acknowledges financial support from the German Ministry of Education and Research project (0315412). T.N.R. acknowledges financial support from Portland General Electric and Portland State University. S.H.S. acknowledges financial support from the US Department of Agriculture National Institute of Food and Agriculture (2013-67009-21008) and the Tree Biosafety and Genomics Research Cooperative at Oregon State University.
Conservation of Nassau grouper
Hybrid-poplar tree plantations provide a source for biofuel and biomass, but they also increase forest isoprene emissions. The consequences of increased isoprene emissions include higher rates of tropospheric ozone production, increases in the lifetime of methane, and increases in atmospheric aerosol production, all of which affect the global energy budget and/or lead to the degradation of air quality. Using RNA interference (RNAi) to suppress isoprene emission, we show that this trait, which is thought to be required for the tolerance of abiotic stress, is not required for high rates of photosynthesis and woody biomass production in the agroforest plantation environment, even in areas with high levels of climatic stress. Biomass production over 4 y in plantations in Arizona and Oregon was similar among genetic lines that emitted or did not emit significant amounts of isoprene. Lines that had substantially reduced isoprene emission rates also showed decreases in flavonol pigments, which reduce oxidative damage during extremes of abiotic stress, a pattern that would be expected to amplify metabolic dysfunction in the absence of isoprene production in stress-prone climate regimes. However, compensatory increases in the expression of other proteomic components, especially those associated with the production of protective compounds, such as carotenoids and terpenoids, and the fact that most biomass is produced prior to the hottest and driest part of the growing season explain the observed pattern of high biomass production with low isoprene emission. Our results show that it is possible to reduce the deleterious influences of isoprene on the atmosphere, while sustaining woody biomass production in temperate agroforest plantations.
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Monson, R. K., Winkler, B., Rosenstiel, T. N., Block, K., Merl-Pham, J., Strauss, S. H., ... & Neice, A. A. (2020). High productivity in hybrid-poplar plantations without isoprene emission to the atmosphere. Proceedings of the National Academy of Sciences.