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From Wikipedia, the mode of action of the non selective herbicide Glufosinate is:

Phosphinothricin is an glutamine synthetase inhibitor that binds to the glutamate site. Glufosinate-treated plants die due to a buildup of ammonia and corresponding decrease in pH in the thylakoid lumen, leading to the uncoupling of photophosphorylation. The uncoupling of photophosphorylation causes the production of reactive oxygen species, lipid peroxidation, and membrane destruction.

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Now, in this article from the University of California (Weed control, management, ecology, and minutia), it states:

Researchers in Malaysia reported a few years ago on a population of goosegrass resistant to glufosinate in vegetable and orchard systems (Lee L J & Ngim J (2000). A first report of glyphosate-resistant goosegrass (Eleusine indica (L) Gaertn) in Malaysia. Pest Management Science, 56, 336-339). For a number of years this was the only reported case of resistance to this herbicide.

What would have to happen in the weed for it to become resistant to this chemical/mode of action, and what would initiate this process?

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  • $\begingroup$ Can you add real citations (Author, year, journal, volume, page) or links to the PubMed (or where ever this can be found)? Than we can have a look at the articles without having to find them first. $\endgroup$ – Chris Jan 29 '15 at 18:40
  • $\begingroup$ I think a general resistance strategy is to pump the offending molecule out of cells. I don't know if that applies here, but I wouldn't be surprised. $\endgroup$ – user137 Jan 29 '15 at 19:04
  • $\begingroup$ @Chris still looking for those $\endgroup$ – J. Musser Jan 29 '15 at 20:48
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Phosphinothricin is a metabolite from the bacteria Streptomyces viridochromogenes which has a protein called phosphinothricin N-acetyltransferase (PAT). This Protein inactivates the phosphinothricin which is the reason why S. viridochromogenes is not dying from it. If you want a plant to be resistant to phosphinothricin you can add the gen for the PAT protein to the plant genom. This is also described in this paper about herbicide-tolerant crobs.

An explanation for the resistant goosegrass could be that somehow it got the gen for PAT, maybe by horizontal gen transfer from S. viridochromogenes.

In your case the publication which is cited in your source contains another possibility. "We hypothesize that reduced herbicide translocation is responsible for resistance to both glyphosate and glufosinate in these populations"

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  • $\begingroup$ Yes, this looks to be correct. Mind adding a reference or 2 before I accept? $\endgroup$ – J. Musser Jan 29 '15 at 21:32
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    $\begingroup$ I learned this in university this semester, but I'll try to find the publications :) There could be other explanations to your question $\endgroup$ – Oli4 Jan 29 '15 at 21:41

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