High-throughput in vitro culture system targeting genetic transformation in sugarcane

Abstract

Conventional recombination breeding suffers setbacks for genetic improvement of sugarcane owing to its narrow gene pool, large complex genome, rare flowering, low fertility, long breeding cycle, and complex environmental interactions. However, production of transgenic plants can be a better alternative to improve quality traits and resistance to biotic and abiotic stresses. The authors report a ready in hand efficient in vitro culture protocol for genetic transformation in a popular sugarcane cv. Sabita (CoOR 03151) of Odisha. 2, 4-D at 3.0 mg/l resulted in highest callus induction frequency (87.8%) with white, friable, and nodular embryogenic calli suitable for plantlet regeneration. 2 mg/l BAP resulted in moderately higher number of shoots/responsive callus and higher percentage of plant survival. However, addition of TDZ (0.05 m/l) with 2 mg/l BAP in R medium (modified MS) may be considered optimum for regeneration of profuse healthy plantlets. A combination of PBZ (0.05 mg/l) with BAP (2 mg/l) and TDZ (0.05 mg/l) revealed profuse multiple shoots (25 microshoots/responsive callus) and higher percentage of survival during follow-up plant establishment than above hormonal supplementation. Among various hormone recipes in MS medium with 3.0 mg/l NAA resulted in excellent rhizogenesis response (88.0%) with more or less normal rooting within 2 weeks. The above efficient and highly reproducible in vitro culture system can be amenable for genetic transformation in this crop.