Gamborg s medium

Arabidopsis thaliana wild type Columbia (Col-0) and Atgun1 T-DNA insertion line SAIL_ 290_D09 were used in this study. Arabidopsis seeds were sterilised with chlorine gas for 2-4 hours and grown on sterile ½ MS medium (PhytoTech Labs) under long-day conditions (16 hours light 8 hours dark) at 100 μmol.m -2 .sec -1 at 22 °C unless otherwise mentioned.
M. polymorpha wild-type accessions Takaragaike-1 (Tak-1) male and Tagarakaike-2 (Tak-2) female were kindly provided by Prof. John Bowman, Monash University. M. polymorpha CRISPR knock-out lines Mpgun1-1 and Mpgun1-2 were generated in this study. M. polymorpha plants were grown on sterile ½ Gamborg's medium (Duchefa Biochemie) supplemented with 1.2 % agar under long day conditions (16 hours light 8 hours dark) unless otherwise mentioned. Crossing and spore sterilisation were carried out as described in methods S1.

Arabidopsis seeds were sterilised and plated on ½ MS medium pH 5.7 without sucrose, 0.8 % agar. The plates were placed directly at 4 °C growth room under long day conditions 8 hours dark 16 hours light at 100 μmol⋅m -2 ⋅s -1 . Plants were imaged after 7 weeks.
Spectinomycin and norflurazon treatments of M. polymorpha spores M. polymorpha spores were sterilised and plated on ½ Gamborg's medium (Duchefa Biochemie) supplemented with 1.2 % agar and 500 μg⋅ml -1 spectinomycin or 5 μM norflurazon. The plates were placed under long day conditions for 48 hours, after which the spores were resuspended in 1 ml of sterile water, transferred into a microcentrifuge tube and spun down at 6,000 rpm for 1 minute. The water was removed, and the spore pellet flash-frozen in liquid nitrogen.