Cross section of genetic diversity in mainland and insular populations of Costus speciosus (Koen ex. Retz.) Sm. using SPAR markers reveal patterns linked to allopolyploidy and biogeography

Costus speciosus (Koen ex. Retz.) Sm. is a major source of diosgenin, used for the commercial synthesis of cortisone, sex hormones and contraceptives. The genetic diversity analysis in wild populations of C. speciosus from 3 biogeographic regions viz., Western Ghats (WG), Eastern Ghats (EG) and Andaman and Nicobar Islands (AN) were done using 2 different Single Primer Amplification Reaction (SPAR) methods. A total of 70 accessions spanning these regions were used in the present study. The assay yielded a total of 314 amplicons of which 268 were polymorphic, exhibiting 85.35% of polymorphism. The prevalence of high rate of genetic differentiation (mean Gst = 0.90) and low gene flow (mean Nm= 0.06) are the main attributes of the observed low diversity in these populations. The accessions clustered broadly under 2 major groups corresponding to the three biogeographic zones with insular populations diverse from the mainland. This was further resolved by AMOVA analysis. C. speciosus is found to exist in different cytotypes exhibiting allopolyploidy. The differences in distribution and genetic fitness of the population from EG and WG may be attributed to the allopolyploid nature of the taxa. In the present study, Island populations comprise very low heterozygosity (Ht = 0.10) suggesting that the rate of fixation is more in these populations. Similarly, the rate of gene flow was almost absent (Nm = 0.02). The higher levels of genetic similarity (0.99) may be due to an increase in fixation of the genes resulting from allopolyploidy. This is the first study on comparative genetic diversity of C. speciosus using SPAR markers

Enhanced production of lupeol through elicitation in in vitro shoot cultures of snake grass (Clinacanthus nutans)

Clinacanthus nutans (Acanthaceae), generally known as ‘snake grass’, has diverse uses in customary system of herbal medicine. The species is endowed with various bioactive compounds exhibiting extensive pharmacological properties. The present investigation focused on elicitor-intervened in vitro shoot biomass cultivation and scale-up production of the anti-cancerous compound ‘lupeol’, one of the foremost constituents in this species. For the augmented production of lupeol, the shoot cultures were elicited with various concentrations of yeast extract (YE), chitosan and methyl jasmonate (MeJA). Maximum shoot biomass yield and production of lupeol was detected in MS medium supplemented with 1.0 mgl-1 BA and 400 mgl-1 YE. The petroleum ether extracts of selected samples upon TLC analysis proved Rf values corresponding to lupeol. HPTLC analysis revealed that the sample treated with YE displayed relatively higher amount (975.50 ng) of lupeol than the in vivo plant (713.69 ng). Hence the in vitro shoot culture system with elicitor (YE) treatment propose an appropriate method for the elevated synthesis of lupeol which can be scaled up via bio-reactor technology in doing so profiting the pharmaceutical appliances