High efficiency plant regeneration and genetic fidelity of regenerants by SCoT and ISSR markers in chickpea (Cicer arietinum L.)

Abstract

High efficient and repeatable in vitro regeneration protocol was established from embryo axis, half-seed, axillary meristem, and cotyledonary node explants of chickpea. Various concentrations and combinations of various plant growth regulators (PGRs) were employed to induce multiple shoots, shoot elongation and rooting of shoots to obtain complete plantlets of chickpea. The pretreatment of seeds with 6-benzyl aminopurine (BAP) at 1.0 mg l−1 was found to significantly increase the multiple shoot regeneration from the all explants tested. Among three PGRs such as BAP, kinetin (KIN) and thidiazuron (TDZ) tested for multiple shoot induction; BAP at 2.0 mg l−1 produced the maximum number of shoots in all tested explants. The maximum number of shoots (48.80 shoots/explant) was attained from the embryo axis explant followed by half-seed (32.76 shoots/explant), axillary meristem (28.34 shoots/explant) and cotyledonary node explant (18.47 shoots/explant) on medium augmented with 2.0 mg l−1 BAP along with 0.05 mg l−1 Indole-3-butyric acid (IBA). The optimum percentage of shoot elongation response was recorded (96.68%) on medium fortified with IAA (0.05 mg l−1), GA3 (1.0 mg l−1) and BAP (1.0 mg l−1) with an average shoot length of 8.82 cm. The elongated shoots were successfully rooted in medium augmented with 2.0 mg l−1 IBA. The complete plants were acclimatized in the greenhouse with a survival rate of 72%. The plantlets regenerated from four explants appeared to be morphologically similar to mother plants. The genetic fidelity of in vitro regenerated plants was evaluated using Start Codon Targeted and Inter simple sequence repeats molecular markers. The in vitro regenerated plants from all four explants were found to be the true to type with their mother plant. The in vitro protocol presented in the study should offer as a feasible system for chickpea genetic transformation. An efficient and reproducible in vitro regeneration protocol was established for chickpea. Application of different concentrations and combinations of PGRs was found to enhance multiple shoot induction, shoot elongation, rooting and acclimatization of in vitro regenerated plants in field conditions, and further evaluated genetic fidelity using molecular markers.