Discovery of bud-break gene could lead to trees adapted for a changing climate

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.

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Keerti Mishra