Indirect somatic embryogenesis and genetic homogeneity assessment in Plectranthus bourneae Gamble an endemic plant to Western Ghats of Tamil Nadu, India

Abstract: An effective somatic embryogenesis protocol was established for Plectranthus bourneae an Endemic plant to Western Ghats of Tamil Nadu, India. High frequency (77.28 %) of embryogenic callus was achieved from leaf explants on Murashige and Skoog (MS) medium supplemented with 0.5 mg/L 2,4- dichlorophenoxyacetic acid (2,4-D). The embryogenic callus was subcultured in a combination of 0.5 mg/L 2,4-D and 50 mg/L glutamine (GLU) which produced somatic embryos(84.22 %). Different stages of embryos (globular, heart, torpedo and cotyledonary stage) were observed. Maturation and the frequency of somatic embryo germination increased when transferred onto half-strength MS medium containing 0.5 mg/L gibberellic acid (GA3) and 0.5 mg/L 6-benzyladenine (BA). Plantlets were acclimatized successfully with 90 % survival. Histological studies revealed the development of primary and secondary embryos. The genetic fidelity of mother plants and in vitro raised plants was established by inter-simple sequence repeat (ISSR) markers. The established protocol assists the rapid production of true-to-type plants by somatic embryogenesis and hence could provide a valuable target material for genetic transformation experiments.