Establishment of in vitro shoot tips regeneration system of foxtail millet and obtainment of transgenic plants of SiSERK1

Abstract Foxtail millet (Setaria italica) would be suitable as a model plant of C4 plants given its small genome (about 470 MB) and diploid self-pollination. However, the study of foxtail millet faces the problem of low efficiency of explant regeneration and genetic transformation. In this study, a new genetic transformation system of Yugu1 foxtail millet is established with in vitro shoot tips as the explant, and, the concentrations of 6-BA and kanamycin are optimized. It is found 0.5 mg L-1 6-BA and 25 mg L-1 kanamycin are the most suitable in terms of the differentiation rate of shoot tips and survival rate of differentiated seedlings. In addition, 12 transgenic foxtail millets of SiSERK1 are identified by resistance screening and PCR. The insertion site of one line of the transgenic plants chosen at random is further identified. The results of qRT-PCR show that the expression of SiSERK1 gene in transgenic plants is significantly higher than that in wild-type plants. A new method of generation of material for further study of SiSERKs is provided for foxtail millet genetics and breeding.