2.1. Generation of TILLING mutants
B. napus (canola cultivar DH12075) seeds were used to generate
three BnFUS3 TILLING mutant lines, CT1296-2 (M1), CT1508-3 (M2)
and CT0831-1 (M3) with the method described in http://www.
botany.ubc.ca/can-till/and Gilchrist et al. (2013). In short, surfacesterilized
seeds of B. napus were mutagenized with EMS (Ethyl
methanesulfonate) and allowed to grow and produce progeny.
Plants obtained from mutagenized seeds were transferred to soil
and grown in a greenhouse until maturity. Seeds were used to
produce second generation of plants which were grown until
flowering, at which point leaves were taken from each plant for
DNA extraction. Plants were allowed to grow until they had produced
a minimum of 100 seeds. Upon maturity, seeds were dried
and stored. Samples of DNA from leaf tissue were used as templates
in polymerase chain reactions (PCR) with the primers bn36-4R and
bn36-5L (Supplementary Table 1), as described by Gilchrist et al.
(2013) and Colbert et al. (2001). These PCR products were then
digested with Celery Juice Extract (CJE) (Till et al., 2004), which
contains an endonuclease that specifically cleaves the single base
pair mismatches resulting from heterozygous point mutations. The
digested DNA was run on a denaturing polyacrylamide Li-cor gel in
order to find DNA populations carrying a mutation in BnFUS3. Upon
the identification of the mutation, the procedure was repeated
using DNA from individuals that exhibited the mutation in the
primary screen.