Development of an efficient transformation system in eggplant (Solanum melongena L.) using the phosphomannose isomerase (PMI) gene as the selectable marker
摘要
A highly efficient Agrobacterium-mediated genetic transformation procedure has been demonstrated in eggplant (Solanum melongena L.) using the phosphomannose isomerase (PMI/ManA) gene, which was employed as a selectable marker using mannose as a source of carbohydrate. The pre-cultured cotyledons were dipped for 10 min in the suspension of Agrobacterium tumefaciens strain LBA4404 with the PMI gene construct, then co-cultivated for two days. The co-cultivated explants were shifted to the selection medium containing mannose (10 g/l), sucrose (20 g/l), and cefotaxime (500 mg/l) cultured and putatively transgenic shoots were recovered after four to six weeks. The putatively transgenic shoots were rooted on the medium containing mannose (10 g/l), sucrose (20 g/l) and IAA (5.71 µM). The putative transgenic plants were hardened and acclimatized under greenhouse conditions. The T0 transgenic plants showed the stable integration of the PMI gene using PCR analysis. The transgenic plants were validated using histochemical gus assay. The leaf segments of putatively transformed plants were examined with chlorophenol red assay, and the transformed plants expressing the PMI gene changed the red colour to orange or yellow. The transgenic plantlets with the PMI gene exhibited morphologically similar characteristics with the control plants. The present transformation procedure using the PMI gene as a selectable marker gene will be feasible for generating novel germplasm with different candidate genes with genetic transformation and genome editing tools devoid of several antibiotics or herbicides.