Genetic diversity and structure revealed by genomic microsatellite markers in Centella asiatica (L.) Urb., a plant with medicinal potential

 Abstract

Background: Around the world, medicinal plants are utilised for various purposes. Centella asiatica is one of the important medicinal plants widely used in many medicinal systems. Nevertheless, analysis of the genetic diversity would pave the way for its most suitable utilisation.

Methods and results: The present study analyses the genetic diversity and structure of eighty C. asiatica accessions collected from the southern states of India, using ten genomic microsatellite markers. The mean Nei’s gene diversity (0.46) indicates considerable genetic diversity. Analysis of molecular variance (82.48%) exhibited significant genetic variance between samples within the population. The cluster analysis brought out the structure of the analysed populations as three subpopulations based on the genetic differentiation.

Conclusions: The study showed significant intra-population variation, predominant inbreeding and population differentiation in C. asiatica. The findings will help better understanding of the genetic structure and gene pool of the plant.

Full article link: https://rdcu.be/cAvFI

Intraspecific genetic variability, differentiation and evolutionary relationships revealed through microsatellite loci in seven economically important species of Calamus L.

Kurian, B., A. S. Hemanthakumar, Jacob J, Wickneswari R, Choong C Y, Sarmah P, Shefeek S, Vishnu V N, Sajithkumar S V, and K K Sabu. 2019. Intraspecific genetic variability, differentiation and evolutionary relationships revealed through microsatellite loci in seven economically important species of Calamus L. Journal of Forestry Research DOI: 10.1007/s11676-019-00984-z

Abstract
Population density, species richness and critical population parameters are crucial in determining the levels of gene diversity in dioecious species of the genus Calamus. The extent of intraspecific and intrageneric genetic variability in Calamus from the southern Western Ghats of India was studied using 26 microsatellite markers by sampling 227 individuals belonging to seven economically important species. The heterozygosity of microsatellite loci ranged from zero to 0.78. Average gene diversity within species was 0.13; in all species it was 0.18 and amongst species was 0.06. The Shannon Information Index was the lowest for Calamus metzianus (0.11), whereas it ranged from 0.16 to 0.26 for other species. The expected heterozygosity varied from 0.08 to 0.18. Calamus hookerianus and Calamu travancoricus showed the highest genetic differentiation (44%) revealed through Fst values, whereas the lowest (22%) was observed between Calamus gamblei and Calamu thwaitesii. Population structuring and phylogenetic analysis differentiated the seven species. Due to overexploitation and loss of rare alleles, small populations could lead to fertilization between closely related individuals, resulting in inbreeding and increasing the risk of extinction. This could be important for species such as C. metzianus where allelic polymorphism was 23%, whereas for all other species it was 38% to 46%. Genetic diversity “micro-hotspots” were identified from the protected area network of the southern and central Western Ghats with highest observed heterozygosity. Four micro-hotspots from the Agasthyamalai Biosphere Reserve and the Pushpagiri Wildlife Sanctuary may be possible for long-term conservation programs. The findings of this study lay a strong foundation for strengthening protected area networks, especially areas with intermediate levels of disturbance.

Keywords
Genetic diversity Differentiation Population structure Conservation Microsatellites Calamus spp. 

ISSR and SSR markers reveal sex-specific DNA sequences in three Calamus species from India

Calamus species yields the raw materials for the cane industry. However, the extraction of the cane from the forests is being carried out indiscriminately without considering the sustenance of the species. Plants of both sexes should co-exist for reproductive success. The sex of Calamus plants can be identified only after flowering and hence proper planning of managed forestry practices cannot be accomplished. A study was carried out in this background and male specific ISSR markers for C. tenuis and C. flagellumand SSR markers for C. thwaitesii were identified. The diagnostic potential of these markers can be exploited to sex the Calamus species at the seedling stage for proper breeding and agroforestry management.

This article has just been published:

Title ISSR and SSR markers reveal sex-specific DNA sequences in three Calamus species from India Journal Agroforestry Systems, (), 1-5 DOI 10.1007/s10457-016-9952-9

This article is available as 'Online First':  http://link.springer.com/article/10.1007/s10457-016-9952-9

Development of EST-SSR Markers to Assess Genetic Diversity in Elettaria Cardamomum Maton

Elettaria cardamomum Maton is one of the most ancient and valuable spice crops. Cardamom is cultivated following intensive pesticide usage where alleles present in the wild cardamom genotypes could positively contribute towards genetic improvement of the cultivars. However, the genetic map or whole-genome sequence of E. cardamomum is not available and very limited information on simple sequence repeat (SSR) markers are publicly available. We have tested whether SSRs from Curcuma longa can be used to analyze genetic diversity E. cardamomum.

Int J Appl Sci Biotechnol, Vol 3(2): 188-192

N Anjali, Sowmya S Dharan, F Nadiya, K K Sabu

DOI: http://dx.doi.org/10.3126/ijasbt.v3i2.12380  

Keywords: EST-SSR; microsatellite; genetic diversity; Elettaria cardamomum; cardamom; marker development

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