Australian Herbicide Resistance Initiative (AHRI)

Non-target-site glyphosate resistance in Echinochloa colona from WA

The paper “Non-target-site glyphosate resistance in Echinochloa colona from WA” was published in Crop Protection, 2018, vol 112, pp 257-263.

Earlier papers by Gaines et al 2012 Weed Technology and Goh et al 2016 Pest Management Science,  documented a glyphosate resistance Echinochloa population from the irrigated north-west Ord River irrigation region of Western Australia.

AHRI PhD student Sou Sheng Goh studied this population for his PhD research. Among other studies, Goh completed excellent work to identify the mechanistic basis of glyphosate resistance in this Echinochloa population. Goh examined for but did not find EPSPS resistance gene mutations and/or EPSPS gene amplification. Thus Goh established that glyphosate resistance in this particular resistant biotype is NON-target site based.

Goh then examined glyphosate uptake, translocation and metabolism and none of these were responsible for glyphosate resistance.  Thus, Goh established that the known glyphosate resistance mechanisms were not responsible for resistance in this particular biotype.  It can definitively be stated that glyphosate resistance in this Echinochloa biotype is non-target site based and not due to differential rates of glyphosate uptake, translocation or metabolism. Dr Sou Sheng Goh has now returned to Malaysia after his successful PhD studies.

To keep you interested we will soon be able to report on a novel glyphosate resistance mechanism in this particular glyphosate-resistant Echinochloa biotype!

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