Genetic diversity and population structure of three commercial indigenous Aloe species in selected ASALs of Kenya

Abstract

Aloe species are common in arid and semi-arid lands (ASALs) of Kenya and are of economic importance especially for bitter gum production. However, the species is under ecological threat due to unsustainable harvesting from the wild. The objective of this study was to evaluate genetic diversity and population structure of three commercially exploited indigenous Aloe species; A. secundiflora, A. turkanensis and A. scabrifolia.The study was carried out in fifteen populations of Aloe species in their wild habitat where their geographic distribution was surveyed and populations delineated. Within each population, 30 trees were sampled at a distance of 100 m apart where leaf tissues were collected for DNA isolation and analysis using modified Cetyl trimethyl ammonium bromide (CTAB) method. Randomly amplified polymorphic DNA (RAPDs) and Inter-simple sequence repeats (ISSR) markers were used to determine the genetic diversity and population structure. Ten RAPD and seven ISSR discriminative primers with the highest value of genetic diversity were selected to genotype three indigenous Aloe species. The genetic similarity was performed using Popgene 1.3.1; hierarchical UPGMA cluster analysis and principal coordinate analysis were performed using Genalex 6.5. To map genetic structure and gene pools, both Structure and Structure Harvester statistical packages were used. From the results, A. secundiflora species was the most distributed in the surveyed ASALs. There was high genetic variation among and within the populations. The combined use of ISSR and RAPD revealed high variations among the populations as compared to when either of them used singly. Genetic variation was highest within secundiflora species and least within turkanensis species. Maralal secundiflora population had the highest genetic variation. The study exhibited a population genetic structure with three major clusters which corresponded to the three Aloe species with minimal reproductive crossing among them. It is therefore, recommended to undertake biophysical studies to determine the advantages of A.secundiflora that has over the other species. In addition, Maralal sec population should be conserved ex-situ because of its high genetic diversity while both ISSR and RAPD markers should be prioritized in Aloe genetic studies as they reveal high variation.

Diversity of Culture dependent endophytic bacteria isolated from leguminous agroforestry trees in western Kenya

“…Horizontal gel electrophoresis (Thistle Scienti c Ltd, USA) was used to estimate the purity on a 1% (w/v) agarose gel at 100V for 40min. The gel was stained with SYBR Safe dye (Invitrogen 10,000x concentrate in DMSO)and visualized under UV according to Adienge et al [30].…”

Antibacterial kinetics and phylogenetic analysis of Aloe vera plants

“…Inhibition zones produced were interpreted according to CLSI guidelines (2016) [13]. Minimum inhibitory concentration (MIC) of each antibiotic was evaluated with the use of standard broth micro-dilution assay [14], and isolates showing antibiotic MIC of >16 µg/mL were selected as resistant.…”

Genetic diversity and population structure of Eurycoma apiculata in Eastern Sumatra, Indonesia

“…RAPD markers have weaknesses, namely low reproductive ability (low reproducibility) and dominant properties (Weising 2005), but it can be overcome through improved laboratory techniques, scoring procedures, and the use of analysis of molecular variance (AMOVA) (Nybom 2004;Weising 2005;Excoffier et al 2007). Although RAPD has several drawbacks, the use of RAPD markers in population genetic diversity studies has been popular in various of plants species such as Plumbago zeylanica (Panda et al 2015), Pinus merkusii (Tuong et al 2016), Cassia tora (Tilwari et al 2016), Panax ginseng (Wang et al 2016), Aloe species (Adienge et al 2019), Silybum marianum (L.) Gaertn (Hamouda 2019). This study aims to assess genetic diversity within and among populations of pasak bumi (E. apiculata) based on the Random Amplified Polymorphic DNA (RAPD) marker, and to determine populations to collect E. apiculata genetic material for conservation and breeding programs.…”