Isolation and characterization of microsatellites for the endangered endemic tree Nothofagus alessandrii (Nothofagaceae).

Cristian Torres-Díaz,Moisés A Valladares,Marco A Molina-Montenegro,Freddy Mora-Poblete

doi:10.1007/s11033-021-06291-3

Abstract

Nothofagus alessandrii (Nothofagaceae) is one of the most endangered trees from Chile due to high rates of habitat disturbance caused by human activities. Despite its conservation status, few molecular markers are available to study its population genetic, connectivity and to assist reproduction programs. Thus, the species needs urgent actions to restore its original distribution. Novel polymorphic microsatellites from the genome of N. alessandrii were isolated and characterized using high-through sequencing. A total of 30 primer pairs were synthesized and 18 microsatellites were amplified correctly. Polymorphism and genetic diversity was evaluated in 58 individuals from three populations of N. alessandrii. Sixteen of them were polymorphic and the number of alleles in the pooled sample ranged from 2 to 14, the mean number of alleles was 4.81. The mean values of observed heterozigosity (HO) and excepted heterozygosity (HE) are similar in all studied populations. Linkage disequilibrium was found between a few pairs of loci (five out of 263 tests) suggesting that most of the markers can be considered as independent. Significant deviations from Hardy-Weinberg equilibrium (P < 0.05) were found in four loci probably due to low sampling size. Transferability to the congeneric N. pumilio was successful in only four out of the sixteen polymorphic markers. The microsatellite markers developed in this study will be useful to study the genetic diversity and structure and to develop integrated management plans for the conservation of this endangered species.

Highlights

Nothofagus alessandrii (Nothofagaceae), known as “ruil”, is a broad-leaf deciduous tree endemic to the Mediterranean climate zone of central Chile (35-36oS).The species is among the most primitive species within the genus [1, 2] and has been considered as a “living fossil” [3]
The species is restricted to a narrow latitudinal range (116 km) 52 having a narrow area of occupancy (755 km2)
From the last decade of the XIX century, the forest dominated by N. alessandrii became increasingly reduced and fragmented

Summary

Introduction

Nothofagus alessandrii (Nothofagaceae), known as “ruil”, is a broad-leaf deciduous tree endemic to the Mediterranean climate zone of central Chile (35-36oS).The species is among the most primitive species within the genus [1, 2] and has been considered as a “living fossil” [3]. Nothofagus alessandrii (Nothofagaceae), known as “ruil”, is a broad-leaf deciduous tree endemic to the Mediterranean climate zone of central Chile (35-36oS). The International Union for Conservation of Nature [IUCN] classified N. alessandrii as endangered in 1997 [4], status that is maintained nowadays [5]. The species is restricted to a narrow latitudinal range (116 km) 52 having a narrow area of occupancy (755 km). From the last decade of the XIX century, the forest dominated by N. alessandrii became increasingly reduced and fragmented. The species was over exploited for wood (posts and poles) being afterwards replaced by plantations of wheat, and more recently, by Pinus radiata and Eucalypthus globulus. In the last decades the species has been threatened by anthropogenic origin forest fires, which have increased their intensity and frequency [6]

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