In Vitro Regeneration and ISSR-Based Genetic Fidelity Analysis of Orthosiphon stamineus Benth

Orthosiphon stamineus has been widely used as traditional remedy for various illnesses and diseases, such as cardiovascular diseases and epileptic seizures. In this study, direct regeneration through nodal segment of this species was attempted using Kinetin (6-Furfurylaminopurine) and IAA (indole-3-acetic acid). Optimum regeneration media was identified as MS media supplemented with 2.0 mg L-1 Kin plus 0.5 mg L-1 IAA. This yielded the highest number of shoots (5.57 +/- 0.42) and leaves (20.53 +/- 1.91) per explant. Acclimatization of the resulting in vitro regenerants was successful in all potting mixtures tested. However, potting mixture PF (1:1:1 ratio of black soil/red soil/compost) was identified as the best medium for acclimatization of this species, as it yielded 100% survival percentage after 90 days of acclimatization. Ten in vitro regenerants of O. stamineus were randomly collected after the third subculture and subjected to genetic variation analysis using inter-simple sequence repeat (ISSR) markers. Out of 20 ISSR markers tested, 10 working primers were observed to produce satisfactory amplification of bands, with an average of 7.11 bands per primer. A total of 610 bands were produced by the 10 primers. The percentage of polymorphism was observed to be very low, yielding only 7.32% polymorphism among all samples. Jaccard dissimilarity analysis was also conducted and very low genetic distance (about 0.1) was found among the in vitro regenerants and between the regenerants with the mother plant, thus ascertaining the clonal nature of the plantlets produced in this study.