Abstract: With the increase in human demands for energy,
purpose-grown woody crops could be part of the global
renewable energy solution, especially in geographical
regions where plantation forestry is feasible and economically
important. In addition, efficient utilization of woody
feedstocks would engage in mitigating greenhouse gas
emissions, decreasing the challenge of food and energy
security, and resolving the conflict between land use for
food or biofuel production. This review compiles existing
knowledge on biotechnological and genomics-aided
improvements of biomass performance of purpose-grown
poplar, willow, eucalyptus and pine species, and their
relative hybrids, for efficient and sustainable bioenergy
applications. This includes advancements in tree in vitro
regeneration, and stable expression or modification of
selected genes encoding desirable traits, which enhanced
growth and yield, wood properties, site adaptability, and
biotic and abiotic stress tolerance. Genetic modifications
used to alter lignin/cellulose/hemicelluloses ratio
and lignin composition, towards effective lignocellulosic
feedstock conversion into cellulosic ethanol, are also
examined. Biotech-trees still need to pass challengeable
regulatory authorities’ processes, including biosafety
and risk assessment analyses prior to their commercialization
release. Hence, strategies developed to contain
transgenes, or to mitigate potential transgene flow risks,
are discussed.
Keywords: bioenergy; Eucalyptus; genetic modification;
Populus; short-rotation trees.