Establishment of Brassica rapa rapa hairy root lines and their maintenance
The eGFP Brassica rapa rapa hairy root lines were developed by BIOPI (Plant Biology and Innovation, Amiens, France) resulting from transformation with a construct portraying a double 35S promoter-SP-His tag-eGFP-CaMV polyA as described by Huet et al (2014). Similarly, the human alpha-L-iduronidase (IDUA) B. rapa rapa hairy root line was developed with the same vector set up but as a gene of interest encoding IDUA, as presented by Cardon et al. (2019).
Fresh hairy roots were subcultured every three weeks onto solid modified Gamborg B5 medium containing 10-fold higher concentrations of copper sulfate and cobalt chloride, and no casein when compared to the original Gamborg B5 (Oksman-Caldentey et al., 1991) and grown in the dark at +24°C. Prior to inoculation of liquid media, the hairy roots were subcultured on solid plates for seven days as a standardized time.