IN VITRO REGENERATION AND TRANSFORMATION OF APPLE (Malus domestica Borkh.) ROOTSTOCK MALLING 7 USING RICE CHITINASE GENE

Abstract

In most of the fruit crops, the low frequency of Agrobacterium mediated genetic transformation hampers the respective transgenics production. Hence, it is pre-requisite to understand and optimize the different parameters involved directly or indirectly in Agrobacterium mediated transformation. A. tumefaciens strain LBA4404 harboring the transforming vector pCAMBARchi11 containing the rice chitinase gene (chi11) and hygromycin phosphotransferase (hpt) and phosphinothricin acetyl transferase (bar) genes was used for carrying out genetic transformation of apple (Malus x domestica Borkh.) rootstock M7. Two explants viz. leaf and internodal segments were involved in regeneration and resulted 24.37% and 60.58% shoot regeneration, respectively. The obtained putative transformants were selected on full strength MS medium containing 5 mg l -1 hygromycin and 500 mg l -1 cefotaxime. Two days pre-culturing and 96 hours co-cultivation was found effective for procuring maximum number of hygromycin resistant shoots. Putative transgenic shoots were multiplied separately and rooted on root induction medium containing 5 mg l -1 hygromycin. Further, PCR analysis was done using chitinase gene specific primers and two apple transgenic lines confirmed the integration of chi11 gene by yielding 237 bp and 584 bp amplified products, respectively.

Boosting carotenoid content inMalus domesticavar. Fuji by expressingAtDXRthrough anAgrobacterium‐mediated transformation method

“…where the proliferation medium was supplemented with GA 3 . The use of M4 supplemented with GA 3 and IBA (M4 + GA3 + IBA) increased the total amount of shoots up to 2.2% of efficiency when total induced calli is considered, which is similar to that reported for apple rootstock (Sharma, Modgil, & Sharma, 2017). In the case of other apple varieties such as Gala, Junami, Mitchgla, and Wellant, 0.55%, 0.57%, 0.12%, and 0% transformation efficiency were obtained, respectively, when the selection method was based only in the visual production of red anthocyanins (Krens et al, 2015).…”