Researchers Develop Imidazolinone Herbicide Tolerant Borage

Borage (Borago officinalis) is an annual herb that produces a high level of gamma-linolenic acid (GLA) in its seed. Due to the recognized health benefits of GLA, borage is now commercially cultivated worldwide. However, an herbicide tolerant variety for effective weed management has not yet been developed. The team of Dongyan Song from the University of Saskatchewan in Canada developed mutant borage lines tolerant to the herbicide imidazolinone.

The team used ethyl methanesulfonate (EMS), a substance capable of producing random mutations, on mature borage seeds to produce a mutant population. The population was then screened using an herbicide treatment and two imidazolinone-tolerant lines were identified. Analysis of the two acetohydroxyacid synthase (AHAS) genes, AHAS1 and AHAS2, in the mutant (tolerant) and wild type (susceptible) borage plants showed that single nucleotide substitutions occurred in both genes in the two tolerant lines.

A marker was also developed to differentiate the homozygous susceptible, homozygous tolerant and heterozygous borage plants. A final herbicide dose response test indicated that lines with the AHAS1 mutation could tolerate four times the normally used field concentration of imidazolinone herbicide.

For more information on this study, read the article in Plant Science.