UBC researchers have discovered a key mechanism that -- much like a construction site foreperson -- controls the direction of plant growth as well as the physical properties of the biopolymers that plants produce.
The finding is a major clue in a 50-year-long quest to explain how plants coordinate the behaviour of millions of cells as they grow upward to compete for light, penetrate soil to obtain nutrients and water, and even open petals to flower.
"We've known for decades that structures in plants called microtubules act as scaffolding to define the direction of cell expansion," says Professor Geoffrey Wasteneys, a UBC botanist and Canada Research Chair in Plant Cell Biology.
"These are tiny multipurpose cylinders that grow, shrink and self-organize to transport cargo, capture and position large structures such as chromosomes, and establish the shape of cells. But we haven't been able to determine how these tiny microtubules are organized into scaffolds in the first place."
An interdisciplinary team of plant cell biologists and mathematicians led by Wasteneys discovered that the inherent geometry of the cell itself plays an important role in the self-organization of microtubules into parallel arrays that guide cell growth and division. They also identified that a protein called CLASP plays a key role as a foreperson, modulating the geometric constraints of the cell.
Their findings will be published in the August 16 issue of the journal Nature Communications.
The research team used a specialized microscope that collects 3D images of plant components genetically engineered to fluoresce when irradiated with specially filtered light. They observed a striking difference in the way microtubules were arranged in normal plants compared to those of a dwarf mutant that fails to produce CLASP.
"Paradoxically, the microtubules appeared to be better organized in the severely stunted mutant plants than
|Contact: Prof. Geoffrey Wasteneys|
University of British Columbia