Improving in vitro leaf disk regeneration system of sugarcane (Saccharum officinarum L.) with concurrent shoot/root induction from somatic embryos

Genome engineering experiments are impeded by poor performance of regeneration systems. The present study was aimed at establishing a short and cost-effective in vitro regeneration system for elite sugarcane cultivars through simultaneous shoot/root induction. The innermost spindle leaf and shoot tip were used as explants. For callus induction, Murashige and Skoog (MS) medium supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D) was used and 5.0 mg/L of 2,4-D supported maximum callus induction (84.5%). Three-week-old calli were treated with different levels of benzylaminopurine (BAP) ranging from 0.00 to 3.5 mg/L in MS medium, where 2.5 mg/L BAP was proven to be the best level for regeneration. In a multiplication and root formation medium, 0.5 mg/L naphthalene acetic acid supported the maximum number of roots per plant. Finally, a direct somatic embryogenesis protocol was established, competent enough for simultaneous root/shoot induction. The results indicated that the plantlets were established within 12 weeks only. This in vitro regeneration protocol was fast and cost-effective and may be used for large-scale in vitro regeneration of sugarcane cultivars to save time and resources. The sugarcane cultivar SPF-234 remained the most responsive, followed by HSF-242 and CPF-246.