Nuclear and chloroplast microsatellites reveal high genetic diversity and structure in Platonia insignis Mart., an endangered species native to the Brazilian Amazon

Wellington F Nascimento,Gabriel Dequigiovanni,Elizabeth A Veasey,Caroline B Garcia,Santiago L F Ramos

doi:10.1590/0102-33062020abb0324

Wellington F Nascimento, Gabriel Dequigiovanni + Show 3 more

Open Access

https://doi.org/10.1590/0102-33062020abb0324

Copy DOI

Abstract

Bacurizeiro (Platonia insignis) is a fruit of the Amazon that, due to anthropic actions, has been suffering serious damage to its genetic diversity. We analyzed the genetic diversity and structure of seven bacurizeiro populations distributed among four Brazilian states and two biomes, the Amazon and Cerrado, based on eight nuclear (ncSSR) and three chloroplast (cpSSR) microsatellite markers. Higher heterozygosity values were found for the Northern populations of Japurá and Marapanim, and the Northeast population of Chapadinha when using ncSSR. Higher diversity indices were also observed for these populations with cpSSR, although higher haplotypic diversity parameters were detected for the two Northern populations. Genetic structure analysis showed the formation of two well defined groups: I - populations from Maranhão and Piauí (Cerrado) and II - populations from Amazonas and Pará (Amazon). Positive and significant correlations were identified between genetic and geographical distances for both ncSSR (r = 0.09; p = 0.0010) and cpSSR (r = 0.11; p = 0.0008), in agreement with the genetic structure analysis. The high genetic structure among populations probably reflects the divergent natural and human selection pressures to which bacurizeiros are subjected in both the Amazon and Cerrado biomes, with higher diversity maintained in the Amazon populations.

Highlights

To reduce the impacts of genetic erosion on plant species, it is of fundamental importance to study the levels of diversity, distribution and genetic structure of their natural populations (Brown & Hodgkin 2015)
Using chloroplast simple sequence repeats (cpSSR) and nuclear simple sequence repeats (ncSSR) markers, the objective of this study was to analyze populations of bacurizeiro in Brazil originating from the North and Northeast regions of Brazil, including two biomes (Amazon and Cerrado), which represents a broader sample when compared to previous studies, aiming to estimate the diversity and genetic structure of these populations, and propose appropriate strategies for the collection and conservation of the species
Positive and significant correlation (r = 0.11; p = 0.0008) was identified between the genetic and geographical distances for the cpSSR data, demonstrating the spatial structure of the genetic material in the sampled geographical area, which is in accordance with the results presented above with ncSSR markers

Summary

Introduction

To reduce the impacts of genetic erosion on plant species, it is of fundamental importance to study the levels of diversity, distribution and genetic structure of their natural populations (Brown & Hodgkin 2015). A wide occurrence area of bacurizeiro is found in the rocky relief further north of South America, called the Guiana Shield, which covers Guyana, French Guiana, Suriname, part of Venezuela and Colombia, and in Brazil, the states of Roraima, Amapá and the north of Amazonas and Pará (GBIF 2020). Because this region has a preCambrian geological formation, being one of the oldest formations on Earth, harboring different forms of life and biomes (Ferreira 2015), the Guiana Shield is more closely related to the possible P. insignis origin scenario. In the transition forest, there is the presence of the Cerrado biome, characterized by intense agricultural activity, where deforestation, long periods of drought and events of forest fires are quite common (Furley 1999; Pivello 2011)

Objectives

Methods

Results

Conclusion