Unraveling the genetic diversity of Ceiba pubiflora (Malvaceae) in isolated limestone outcrops: Conservation strategies.

Seasonally Dry Tropical Forests (SDTFs) located on limestone outcrops are vulnerable to degradation caused by timber logging and limestone extraction for cement production. Some of these forests represent the last remnants of native vegetation cover, functioning as isolated islands. Ceiba pubiflora (Malvaceae) is a tree frequently found on limestone outcrops in the central region of Brazil. This study aimed to evaluate the genetic diversity and identify suitable populations for the establishment of Management Units (MUs) for conservation. Inter-simple sequence repeat markers were employed to assess the genetic diversity in ten populations sampled from the Caatinga, Cerrado, and Atlantic Forest biomes. The species exhibited substantial genetic diversity (HT = 0.345; PLP = 97.89%). Populations SAH, JAN, and MON demonstrated elevated rates of polymorphic loci (> 84.2%) along with notable genetic diversity (He > 0.325). Additionally, these populations were the primary contributors to gene flow. The analysis of molecular variance (AMOVA) indicated that most genetic variation occurs within populations (91.5%) than between them. In the Bayesian analysis, the ten populations were clustered into five groups, revealing the presence of at least three barriers to gene flow in the landscape: 1) the Central Plateau or Paranã River valley; 2) near the Espinhaço mountains or the São Francisco River valley; and 3) around the Mantiqueira mountain range, Chapada dos Veadeiros plateau, and disturbed areas. A positive and statistically significant correlation was observed between genetic (θB) and geographic distances (r = 0.425, p = 0.008). Based on these findings, we propose the establishment of Management Units in Minas Gerais state, encompassing the (1) southern region (MIN population), (2) central region (SAH population), and (3) north region (MON population), as well as in Goiás state, covering the (4) Central Plateau region. These units can significantly contribute to preserving the genetic diversity of these trees and protecting their habitat against ongoing threats.

Development and characterization of nuclear microsatellite markers for Eremanthus erythropappus and their transferability across related species

BACKGROUND: We developed simple sequence repeats (SSR) for Eremanthus erythropappus (DC.) MacLeish, an endangered tree species endemic to the Brazilian Savanna and Atlantic Forest biomes, and tested their transferability to two closely related Eremanthus species. RESULTS: Using a genomic library enriched with tandem repeat motifs, we identified 16 primer pairs, and characterized them in two populations. Nine primers amplified the expected size fragments and seven SSRs were polymorphic, providing a total of 38 alleles and an average of 4.22 alleles per marker. The polymorphic information content (PIC) ranged from 0.44 to 0.94 with an average of 0.65. The average observed heterozygosity across all loci varied from 0.61 to 1.00. The observed ( HO ) and expected ( HE ) heterozygosity within the two populations varied from 0.65 to 1.00 and from 0.31 to 1.00, respectively. CONCLUSIONS: These newly developed SSR markers are a powerful tool for population genetic analyses and may be useful in studies on species ecology, evolution, and taxonomy.