The Establishment of Two Efficient Transformation Systems to Manipulate and Analyze Gene Functions in Quinoa (Chenopodium quinoa Willd.)

Quinoa (C. quinoa) is considered a gluten-free food with abundant nutrients and high tolerance to multiple abiotic stresses, which is the potential to become a major crop in future. Genetic manipulation will provide powerful tools to investigate the function and mechanism of those important genes in the regulation of quinoa development and stress responses, and further improve the quinoa in the field. However, the efficient plant transformation system for quinoa has not been well developed yet. Here, we established two rapid and efficient transformation systems for quinoa by using hairy roots and agroinfiltration of leaves, which provide useful tools for quick analysis of gene function. Hairy roots were obtained from three types of explants: cotyledon-nod with hypocotyl, cotyledon itself, and hypocotyl pieces. Interestingly, explants of cotyledon-nod with hypocotyl showed the highest transformation efficiency at 67.9%, and cotyledon displayed medium efficiency at 42.2%, while hypocotyl explants with the lowest at 31.6%. We also obtained transgenic quinoa roots successfully in-vivo, which showed low efficiency but provides a potential method to test gene functions in live plants. By using young leaves for agroinfiltration, direct injection showed a better transgenic effect compared with vacuum penetration. In juxtaposition, the transformation systems using both hairy root and leaf infiltration establish an efficient and convenient way to manipulate and analyze gene functions in quinoa, and a potential strategy for transgenic quinoa.