A robust genetic transformation protocol to obtain transgenic shoots of Solanum tuberosum L. cultivar 'Kufri Chipsona 1'.

The genetic transformation of plants is an important biotechnological tool used for crop improvement for many decades. The present study was focussed to investigate various factors affecting genetic transformation of potato cultivar 'Kufri Chipsona 1'. It was observed that explants pre-cultured for 2 days on MS2 medium (MS medium containing 10 µM silver nitrate, 10 µM BA, 15 µM GA3), injured with a surgical blade and co-cultivated with Agrobacterium tumefaciens strain EHA105 [O.D600 (0.6)] for 2 days results in maximum transient β-glucuronidase (GUS) expression. The addition of 100 µM acetosyringone in MS2 medium also increased rate of transient GUS expression in both the explants. Clumps of putative transgenic shoots were regenerated using the optimised culture conditions from leaf and internodal explants. The stable integration of T-DNA was established using histochemical staining for GUS and amplification of DNA fragment specific to nptII and uidA genes. Within the clumps, around 67.85% of shoots showed uniform GUS expression in all the tissues and about 32.15% shoots show intermittent GUS expression establishing chimeric nature. Uniform GUS staining of the tissue was used as initial marker of non-chimeric transgenic shoots. Quantitative expression of nptII transgene was found to be directly proportional to uniformity of GUS staining in transgenic shoots. The present investigation indicated that manipulation of culture conditions and the medium composition may help to get transgenic shoots with uniform expression of transgene in all the tissues of potato cultivar 'Kufri Chipsona 1'. © Prof. H.S. Srivastava Foundation for Science and Society 2020.