Hybrid Poplar Trees Mix Genes to Fine-Tune Their 'Breathing' for a Changing Climate

Stomata, the microscopic pores on plant leaves, are vital for regulating gas exchange and water loss. A new study on two poplar species, Populus trichocarpa and P. balsamifera, explores how their interbreeding, or 'interspecific gene flow', affects this crucial trait across their natural hybrid zone.

Using genomic sequencing and garden experiments, scientists found that while the parent species have distinct stomatal distributions, their hybrids tend to resemble P. trichocarpa. Researchers identified several candidate genes linked to these traits, including one named TWIST, which plays a key role in initiating stomatal development.

Crucially, the study demonstrates that climate is a powerful driver of evolution. By examining different geographic contact zones, the team showed that local precipitation levels shape which parental genes are favoured. This suggests that hybridisation creates a fresh genetic toolkit, potentially boosting the trees' adaptive potential in the face of environmental change.