Lignocellulosic biomass yield enhancement: generation of poplars with an increased sylleptic branching

CBGP research group led by Dr. Isabel Allona has identified a gen responsible of a greater production of branches in poplars. Trees in which the expression of this single gene has been changed don't show any significant changes either in their growth characteristics or in the composition and anatomy of their wood.

Woody crops of fast growing species such as Populus, Salix and Eucalyptus and their respective hybrids, cultured under an intensive management system or short rotation coppice (SRC) have been proposed as an efficient source of lignocellulosic biomass. From a genetic point of view, the amount of biomass that a forest species can produce is a highly complex trait as it represents the combined outcome of many other complex traits, every one of them under polygenic control. On the other hand, it has been described that biomass yield of a young plantation can serve as an early and reasonable indicator of its biomass yield in the ensuing years. The ability of trees to produce the so called sylleptic branches is among the characters determining biomass yield. This type of branching, more frequently found in tropical tree species, develops from lateral buds that outgrow during the same spring in which they are formed without an intervening winter dormancy period. However, in most of the temperate tree species, lateral buds do not outgrow during the season in which they are formed, but require overwinter to outgrow as proleptic branches during the following spring.

Our team has expressed the CsRAV1 gene in the hybrid poplar Populus tremula x P. alba. These trees, in contrast to the wild type ones, develop many sylleptic branches only a few weeks after being planted in soil, but do not show significant changes in their growth characteristics or in the composition and anatomy of their wood. The potential of these trees, in which the expression of a single gene has been changed, to produce a greater amount of biomass makes them promising candidates to establish bioenergy plantations.

Artículo Original:

CsRAV1 induces sylleptic branching in hybrid poplar.