| Crop | Dry Bean |
|---|---|
| Start Date | 2013 |
| End Date | 2018 |
| Principal Investigator | Marsolais, Frédéric , Agriculture and Agri-Food Canada |
| MPSG Financial Support | $50,000 |
| Total Project Funding | $368,550 |
| External Funding Partners | Funding for this project has been provided by Agriculture and Agri‐Food Canada through the AgriInnovation Program and Ontario Bean Growers |
Project Description
This project seeks to develop a commercial variety (-ies) of dry edible bean with tolerance to imazethapyr. Imazethapyr is a group 2 herbicide, a member of the chemical class of the imidazolinones, and is sold under the trade name of Pursuit. Pursuit is used in agronomic production of edible bean. However, navy beans have a low margin of safety with this herbicide. It is anticipated that resistance to imazethapyr will be conferred by a mutation or natural variant of the gene(s) encoding acetolactate synthase or ALS. Imazethapyr works by inhibiting acetolactate synthase, an essential enzyme of branched chain amino acid biosynthesis. In crops resistant to group 2 herbicides, sequence variants of acetolactate synthase are insensitive to inhibition by the herbicide.
This project uses several different approaches to isolate tolerant or resistant lines. Populations of natural accessions and of chemically mutagenized lines are being screened for resistance using field spray and chamber spray methods. The entire germplasm in our jointly operated breeding program was screened for tolerance to higher than recommended rates of imazethapyr in the field in 2013. The 88 plants found with suspected naturally occurring tolerance were tested using spray chamber experiments the following winter. In 2014, progeny from these same plants were again field screened for tolerance. Resulting from this continued screening 29 of these naturally occurring plants were again subjected to spray chamber experiments the following winter. In the field in 2015, a replicated split plot experiment was conducted testing seven of the most promising naturally occurring lines for their performance in the presence or absence of imazethapyr. Another 42 lines sourced from the natural occurring lines as well as from the chemically mutagenized lines were screened both in the presence and absence of Pursuit in a similar non replicated experiment. A small number of accessions have been found to be consistently tolerant to Pursuit in field trials. These accessions are being further characterized using spray chamber experiments.
A stable transformation platform is being developed for genome editing in edible bean using the CRISPR/Cas9 technology. This technology can engineer deletions or point mutations in a gene of interest. Unlike other genetic transformation technology, it can produce an individual without extraneous foreign DNA, thus equivalent to a non-genetically modified plant. So far, an efficient plant regeneration system was developed for edible bean transformation in several varieties. The best regeneration results have been observed for two navy bean varieties (Olathe and AAC Burdett) and one red kidney variety (Montcalm). Fully mature plants with developed seeds have been collected from these regenerated plants and have yet to be tested for viability. The next step being undertaken is a proof-of-concept experiment for edible bean transformation using a foreign gene for resistance to the herbicide Basta (glufosinate ammonium or phosphinotricine). Methods are also being developed to apply genome editing technology to transformed edible bean plants in order to produce plants that are tolerant to the herbicide Pursuit.
Cultivar development and technology transfer will take place through the Guelph edible bean breeding program.