Impact of RAV1-engineering on poplar biomass production: a short-rotation coppice field trial

Abstract

BackgroundEarly branching or syllepsis has been positively correlated with high biomass yields in short-rotation coppice (SRC) poplar plantations, which could represent an important lignocellulosic feedstock for the production of second-generation bioenergy. In prior work, we generated hybrid poplars overexpressing the chestnut gene RELATED TO ABI3/VP1 1 (CsRAV1), which featured c. 80% more sylleptic branches than non-modified trees in growth chambers. Given the high plasticity of syllepsis, we established a field trial to monitor the performance of these trees under outdoor conditions and a SRC management.ResultsWe examined two CsRAV1-overexpression poplar events for their ability to maintain syllepsis and their potential to enhance biomass production. Two poplar events with reduced expression of the CsRAV1 homologous poplar genes PtaRAV1 and PtaRAV2 were also included in the trial. Under our culture conditions, CsRAV1-overexpression poplars continued developing syllepsis over two cultivation cycles. Biomass production increased on completion of the first cycle for one of the overexpression events, showing unaltered structural, chemical, or combustion wood properties. On completion of the second cycle, aerial growth and biomass yields of both overexpression events were reduced as compared to the control.ConclusionsThese findings support the potential application of CsRAV1-overexpression to increase syllepsis in commercial elite trees without changing their wood quality. However, the syllepsis triggered by the introduction of this genetic modification appeared not to be sufficient to sustain and enhance biomass production.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-017-0795-z) contains supplementary material, which is available to authorized users.

Environmentally sensitive molecular switches control diurnal and seasonal growth in poplar

“…Previous results of our laboratory reported that overexpression of CsRAV1 in poplar increased axillary bud outgrowth under LDs (Moreno-Cortés et al, 2012;Moreno-Cortés et al, 2017). Similarly, we found that poplar RAV1oe increased axillary bud outgrowth under LD conditions (Fig.…”

“…Functional studies performed in our laboratory indicated that the overexpression of chestnut RAV1 increased axillary branching under LDs, however the molecular mechanism involved has yet to be determined (Moreno-Cortés et al, 2012;Moreno-Cortés et al, 2017). Similarly, in this thesis, it is shown that overexpression of the poplar RAV1 promoted both higher levels of FT2 gene expression and axillary bud outgrowth under LDs.…”

Manipulation of Growth and Architectural Characteristics in Trees for Increased Woody Biomass Production

“…Overexpression of CsRAV1, a chestnut ortholog of TEMPRANILLO , a regulator of FT ( Castillejo and Pelaz, 2008 ), led to upregulation of a poplar ortholog of FT ( PttFT2 ) expression ( Triozzi et al, 2018 ) and consequently to increased branching both under greenhouse and field conditions ( Moreno-Cortes et al, 2012 , 2017 ). Under field conditions, increased branching led to increased biomass ( Moreno-Cortes et al, 2017 ). Similarly, overexpression of a poplar ortholog of GIGANTEA, a positive regulator of FT , upregulated PttFT2 and increased sylleptic branching in poplar ( Ding et al, 2018 ).…”

Climatic signal in a radial growth of Canadian and Maximovich poplars in south-western Poland

“…Light conditions are of great importance to them in the process of photosynthesis, and, more precisely, its intensity which increases in direct proportion to the intensity of light (Dickmann et al, 2001). In current studies of trees of the genus Populus, researchers mostly focus on using them as biomass, which is a source of renewable energy (Moreno-Cortés et al, 2017;Aylott et al, 2008), on using their wood for construction and industry purposes (Kretschmann et al, 1999), and on pulp for the pulp and paper industry (Przybysz and Przybysz, 2013), as well as its application in the pharmaceutical industry (Belkhodja et al, 2016). Many studies focus on the efficiency of poplar cultivation as related to different lengths of production cycles (Pereira et al, 2016;Lamerre et al, 2015;Moreno-Cortés et al, 2017).…”