Australian Herbicide Resistance Initiative (AHRI) insight #151 - We’ve cracked the P450 code
Australia
February 1, 2021
Written by Peter Newman
Patience, dung beetle!
About 35 years ago a ryegrass population that had been sprayed several times with Hoegrass® (Diclofop) became resistant to that herbicide and cross resistant to Glean (chlorsulfuron) before Glean® or any other ALS herbicide had ever been used in Australia.
P450 enzymes were suspected to be the cause of this cross resistance but it has taken until now to get the definitive evidence.
A very patient group of researchers led by Heping Han from AHRI, including researchers from Bayer and Zheijiang University in China have identified the P450 gene responsible for cross resistance to herbicides of at least five modes of action.
You’re going to love the name of the gene, it’s called:
CYP81A10v7
CYP is short for Cytochrome P450, a superfamily of enzymes. Plants contain hundreds of different P450 enzymes, so to find the specific one that causes this cross resistance is like finding a needle in a stack of needles! Hence the need for extreme patience, high level science, and an international team of molecular biologists.
In simple terms it involves turning up the dimmer switch to full noise on the production of the enzyme so the resistant plants have truckloads of the P450 enzyme that can break down the herbicide before they get to their site of action, or gene overexpression if you want to be technical.
Topics
Species
