Australia
April 12, 2016
Picture yourself as a city slicker driving to work. Between your house and the freeway there are four sets of traffic lights.
On this particular day all of the traffic lights are stuck on red. The city is in chaos with no-one able to get to work. You then spend the rest of your life, in your car, at a red traffic light.
Perish the thought!
This is how 2,4-D resistance works in wild radish.
The traffic lights are transporters that allow 2,4-D to move from cell to cell, and the freeway is the phloem – the plant veins that move sugars and other products around the plant.
AHRI researcher, Dr Danica Goggin, has spent the last three years studying the 2,4-D resistance mechanism in wild radish. She used radioactive 2,4-D to determine that the herbicide was getting stuck in the treated leaf of resistant plants. The 2,4-D couldn’t get to the growing point to kill the plant.
But how?
On the edge of plant cells there are proteins called ABCB transporters that ‘push’ some compounds from one cell to the next. It’s not yet confirmed, but Danica strongly suspects that in resistant plants these transporters (traffic lights) have been modified and no longer move 2,4-D from cell to cell. This means that 2,4-D can’t reach the phloem (freeway), so it stays in the treated leaf where it’s ineffective.
In other words, 2,4-D becomes like a contact herbicide, affecting only the leaves it hits.
For a deeper understanding of how 2,4-D should work, and how wild radish has evolved resistance to 2,4-D click read more below.
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