Abstract
Sorghum is considered a challenging species for transformation due to the limited choice in genotypes that can be transformed and the reliance on callus derived from immature embryos that need to be teased out of developing seeds. We have developed a more practical tissue culture procedure to generate embryogenic callus from leaf whorl explants obtained from 4 week-old seedlings. This procedure offers greater ease of obtaining explants, enables a more rapid turnover of growth chamber or greenhouse plants that can be used for explant collection, and eliminates the dependency on obtaining flowering plants with adequate numbers of seeds. Callus derived from these somatic embryos was amenable to biolistic transformation with DNA-coated gold particles and transformants were shown to express the Cas9 transgene. A comparison between genotypes RTx430 and P898012 indicated that the former was more suitable to tissue culture from leaf whorls based on greater callus induction and regeneration. Callus from both genotypes secreted colored compounds into the medium that we determined to be phenolic in nature, likely 3-deoxyanthocyanidins, based on UV–Vis absorbance profiles and thin layer chromatography. In order to reduce negative impacts of these compounds on regeneration, the addition of activated charcoal (AC) or polyvinylpyrrolidone (PVP) to the culture medium was examined. The addition of 0.5 g L−1 of AC after 4 weeks on callus induction medium accelerated callus regeneration, whereas culturing leaf whorl explants on medium containing 1 g L−1 PVP reduced the production of colored compounds and enhanced callus growth. The use of leaf whorl explants from developing sorghum plants serves as a practical alternative to immature embryos as a source of embryogenic callus and doesn’t require plants to flower.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call