Wood forming tissue‐specific bicistronic expression of PdGA20ox1 and PtrMYB221 improves both the quality and quantity of woody biomass production in a hybrid poplar

Abstract

Summary With the exponential growth of the human population and industrial developments, research on renewable energy resources is required to alleviate environmental and economic impacts caused by the consumption of fossil fuels. In this study, we present a synthetic biological application of a wood forming tissue‐specific bicistronic gene expression system to improve both the quantity and quality of woody biomass to minimize undesirable growth penalties. Our transgenic poplars, designed to express both Pd GA 20ox1 (a GA 20‐oxidase from Pinus densiflora producing bioactive gibberellin, GA ) and Ptr MYB 221 (a MYB transcription factor negatively regulating lignin biosynthesis) under the developing xylem ( DX ) tissue‐specific promoter (i.e., DX 15::Pd GA 20ox1‐2A‐Ptr MYB 221 poplar), resulted in a 2‐fold increase in biomass quantity compared to wild‐type ( WT ), without undesirable growth defects. A similar phenotype was observed in transgenic Arabidopsis plants harboring the same gene constructs. These phenotypic consequences were further verified in the field experiments. Importantly, our transgenic poplars exhibited an improved quality of biomass with reduced lignin content (~16.0 wt%) but increased holocellulose content (~6.6 wt%). Furthermore, the saccharification efficiency of our transgenic poplar increased significantly by up to 8%. Our results demonstrate that the controlled production of both GA and a secondary wall modifying regulator in the same spatio‐temporal manner can be utilized as an efficient biotechnological tool for producing the desired multi‐purpose woody biomass.

Overexpression of a Poplar RING-H2 Zinc Finger, Ptxerico, Confers Enhanced Drought Tolerance via Reduced Water Loss and Ion Leakage in Populus

“…Due to the global climate crisis and the predicted increase of the global population, it is imperative to establish a strategy to make both crops and woody perennials more tolerant to a water-limited environment. Biomass from woody perennials accounts for more than 90% of the total biomass produced on earth, and about 25% of the annual anthropogenic CO 2 emissions can be assimilated during woody biomass formation, which suggests that woody perennials serve as one of earth’s major long-term terrestrial carbon sinks [ 2 , 3 , 4 , 5 ]. Populus is a well-known genus for the production of an ideal woody biomass, because of their fast growth with a suitable wood quality for various applications [ 6 ].…”

The Threat of the Combined Effect of Biotic and Abiotic Stress Factors in Forestry Under a Changing Climate

“…Genetic improvement for combined biotic and abiotic stress tolerance may target either the regulators common to the different stresses or pyramiding of genes governing response to individual stresses (Kissoudis et al, 2014). Recent studies are shedding light on the possibilities of engineering plants for multiple traits (Cho et al, 2019). Thus, improving trees for resistance to combined biotic and abiotic stresses using these techniques may also become possible.…”

Early response to GA3-treatment in the pedicel of table grape genotypes with different susceptibility to berry drop reveals responses elicited in cell wall yield and modification of lignin content

“…(GA) enhanced growth and biomass production [12,13]. In fact, transgenic lines have been engineered to increase bioactive GA and repress lignin biosynthesis in xylem tissue, resulting in enriched biomass destined to liquid fuel production [14,15]. Therefore, it is suggested that the expected effects of GA 3 treatments in vascular tissue could be on cell wall-related processes, which in turn impact on the flexibility of this structure.…”