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Herbicide multiple‐resistance in a Lolium rigidum biotype is endowed by multiple mechanisms: isolation of a subset with resistant acetyl‐CoA carboxylase
Author(s) -
Tardif François J.,
Powles Stephen B.
Publication year - 1994
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1994.tb02978.x
Subject(s) - lolium rigidum , population , biology , acetyl coa carboxylase , weed , lolium , pyruvate carboxylase , herbicide resistance , resistance (ecology) , pesticide resistance , susceptible individual , agronomy , botany , enzyme , poaceae , biochemistry , pesticide , demography , sociology
The development of herbicide multiple‐resistance in weed species represents a major threat to current agricultural practices. The mechanistic basis for herbicide multiple‐resistance has been investigated in a population of the annual grass weed Lolium rigidum Gaud. (annual ryegrass) resistant to herbicides affecting 6 target sites. A subset of the resistant population (R 2 subset) has been isolated by germination on a medium containing the acetyl‐CoA carboxylase (ACCase, EC 6.4.1.2) inhibiting herbicide, sethoxydim ((2‐[1‐(ethoxyimino)butyl]‐5‐[2‐(ethylthio)propyl]‐3‐hydroxy‐2‐cyclohexen‐1‐one)). This 12% R 2 subset of the population is 600 times more resistant to sethoxydim and between 30 to 200 times more resistant to other ACCase inhibitors than the bulk of the R population. The subset has a form of ACCase which is 6 to 55 times less sensitive to inhibition by these herbicides than the enzyme present in the bulk of the resistant or in the susceptible population. There was no difference in the uptake and metabolic degradation of [4‐ 14 C]sethoxydim between the R 2 subset and the unselected R population. These results show the accumulation of different resistance mechanisms in that single population. Furthermore we propose that this accumulation of multiple resistance mechanisms is the basis for herbicide multiple‐resistance in this biotype.