3AGAP, Univ Montpellier, CIRAD, INRAe, Institut Agro, Montpellier, France
*Corresponding author:benziwa.johnson@gmail.com
Abstract
To study the genetic diversity and structure of the forest speciesPterocarpus erinaceus Poir., seventeen polymorphic nuclear microsatellite markers were isolated and characterized, using Illumina MiSeq sequencing technology. Three hundred and sixty five (365) individuals were analysed within fifteen (15) West Africa populations. The alleles’ number for these loci varied from 4 to 30 and 0.23 to 0.82 for the heterozygosity. The seventeen primers designed here will be useful to analyse ecology population and mechanisms of population differentiation of this threaten species.
Keywords: African tree species, genetic diversity, next-generation sequencing, nuclear microsatellites, Pterocarpus erinaceus .
Introduction
Pterocarpus erinaceus Poir. (1823) commonly known as African rosewood is an important tree belonging to the Fabaceae family and native to the Guinean forest-savannah mosaic ecoregion and reported from Senegal to Cameroun (Adjonou et al., 2019; Arbonnier, 2004; Giffard, 1974). Stands of this Leguminous species are especially targeted for timber, service wood fuelwood production and have several medicinal uses (Fontodji et al., 2011; Kokou et al., 2009; Segla et al., 2015). Recent scientific investigations on P. erinaceus international trade have highlighted a considerable increase in export volume for its wood furniture from West Africa countries for Asia, particularly China (Dumenu, 2019; Lawson, 2015). As a consequence of its overexploitation, the Convention on International Trade in Endangered Species of Wild Fauna and Flora classified the species as threatened (CITES, 2016) and it has become the focus of conservation concern in African countries. Because of its high-quality wood, but also as a drought and fire-resistant plant species with traditional medicine uses in sub Saharan Africa (Duvall, 2008; Karou et al., 2003; Ouedraogo et al., 2012), P. erinaceus is a good model species for the study of a sustainable genetic diversity in Pterocarpus genus.
To understand the evolution dynamic of population P. erinaceuspopulations in West Africa in order to establish appropriate and efficient production and conservation strategies, it is necessary to study genetic diversity and structure of its natural stands dynamics. The study also wanted at analyzing the characteristics of mating system existing among individuals and the gene flow. Among various molecular tools used for assess plant genetic diversity, microsatellite simple sequence repeats (SSR) markers are the most widely employed because they are codominant and they possess high levels of polymorphism and stability (De et al., 2017; Morgante and Olivieri, 1993).
In the context of assessing genetic diversity into Pterocarpusgenus, Muller et al. (2006) have developed microsatellite markers forPterocarpus officinalis Jacq. belonging to the Carribean wetland forest species, but especially for P. erinaceus no nuclear microsatellite markers have been identified so far. Owing to the laborious and expensive microsatellites development by conventional methods, next-generation sequencing (NGS) technologies were carried out here. The major advantage of this approach is in generating important volume of sequencing data allowing the identification of large numbers of microsatellite markers (Rico et al., 2013; Senan et al., 2014; Vieira et al., 2016).
We developed here microsatellite markers for P. erinaceus and evaluated their polymorphism in West Africa.
Material and Methods
We sampled nine to thirty adult trees in fifteen populations (Table 1) with a total of three hundred sixty-five trees in four countries of West Africa which are Benin, Burkina Faso, Niger and Togo.
Table 1 : Characteristics of sampled sites for Pterocarpus erinaceus : country location, name of sampling sites, number of tree sampled per site.