Scientists have
confirmed the function of a gene that controls the awakening of trees from
winter dormancy, a critical factor in their ability to adjust to environmental changes
associated with climate change.
While other
researchers have identified genes involved in producing the first green leaves
of spring, the discovery of a master regulator in poplar trees (Populus species) could eventually lead to
breeding plants that are better adapted for warmer climates.
Yordan Yordanov and
Victor Busov at Michigan Tech worked with Cathleen Ma and Strauss at Oregon
State to trace the function of EBB1 in buds and other plant tissues responsible
for setting forth the first green shoots of spring. They developed modified
trees that overproduced EBB1 genes and emerged from dormancy earlier in the
year. They also showed that trees with less EBB1 activity emerged from dormancy
later. "The absence of EBB1 during dormancy allows the tree to progress
through the physiological, developmental and adaptive changes leading to
dormancy," said Busov, "while the expression of EBB1 in specific cell
layers prior to bud-break enables reactivation of growth in the cells that
develop into shoots and leaves, and re-entry into the active growth phase of
the tree."They found that EBB1 codes for a protein that helps to restart
cell division in a part of the tree known as meristem, which is analogous to
stem cells in animals. EBB1 also plays a role in suppressing genes that prepare
trees for dormancy in the fall and in other processes such as nutrient cycling
and root growth that are critical for survival. Altogether, they found nearly
1,000 other poplar genes whose activity is affected by EBB1.
It's unlikely that
plant breeders will use the finding any time soon, Strauss said. Breeders tend
to rely on large clusters of genes that are associated with specific traits
such as hardiness, tree shape or flowering. However, as more genes of this kind
are identified, the opportunity to breed or engineer trees adapted to extreme
conditions will grow.
Made by
Keerti Mishra
