Optimization of various growth promoters under in vitro conditions and characterization of invertase inhibitor genes for reducing loss of sucrose in sugarcane saccharum officinarum l

Abstract

The optimization of different plant growth hormones for callus induction under micropropagation was evaluated using two sugarcane genotypes (CoLk 14201 and Co 15023). Different concentrations of 2,4-D, alone and in combination with other plant growth hormones (Kinetin and BAP), were used for callus induction. Kinetin and BAP, alone and in combination with IBA and NAA, were analyzed for their effects on shoot induction, while NAA alone and in combination with IBA were used for root induction. The best callus response in terms of days to initiation, callus fresh weight (gms), frequency (%), callus color, and texture in CoLk 14201 was observed on MS medium supplemented with 2,4-D (4 mg/L), while in Co 15023, the best response was obtained on MS medium with 2,4-D (3 mg/L) and Kinetin (0.5 mg/L). For shoot induction, MS medium supplemented with Kinetin (2 mg/L) was found to be the most effective for both CoLk 14201 and Co 15023 in terms of days to shoot initiation, number of shoots, shoot length (cm) and shoot frequency (%). The best medium for root induction, in terms of days to root initiation, number of roots, root length (cm) and root frequency (%) was ½ MS supplemented with NAA (2.0 mg/L) for CoLk 14201, while for Co 15023, the best response was observed on ½ MS supplemented with NAA (2.5 mg/L). The present study describes the assessment of genetic fidelity in sugarcane plants regenerated through indirect organogenesis using SSR markers. Analysis of SSR banding patterns generated with 10 primers showed no evidence of somaclonal variation. In sugarcane, invertase inhibitor (INVINH) proteins play a key role in the post-translational regulation of plant invertases, thereby controlling sucrose hydrolysis. We identified two INVINH genes (ShINH1 and ShINH2) from sugarcane genotypes CoLk 14201 and Co 15023, amplified using sugarcane gene-specific primers INH1 and INH2. ShINH1 and ShINH2 are likely to play a regulatory role in sucrose accumulation and may contribute to the improvement of sugar yield and recovery in sugar