Fragmentation effects and genetic diversity of the key semidecidual forest species Metrodorea nigra in Southwestern Brazil

Abstract

ABSTRACT. Studies of genetic diversity in plant species present in the remaining fragments of the Atlantic Forest are very important for understanding their resilience to such a degraded ecosystem. We analyzed the genetic diversity of 3 populations of the high-density understory species Metrodorea nigra St. Hill. (Rutaceae) located in forest remnants in the region of Ribeirão Preto, SP, Brazil (M13-Rib, BSQ-Rib, and FACCrav), by using simple sequence repeat (SSR) and inter-simple sequence repeat (ISSR) molecular markers for conservation purposes. A total of 133 polymorphic loci were observed in 136 inter-simple sequence repeat loci (average of 17 per primer). The Nei genetic diversity (H E ) was relatively high considering all populations (0.31). The BSQ-Rib population exhibited the highest value (0.27), followed by the M13-Rib (0.26) and FAC-Crav (0.24) populations. The simple sequence repeat markers analyzed showed a high number of alleles (K = 104), with an average of 14.85 alleles per locus. The average observed heterozygosity was 0.516 and the average expected heterozygosity was 0.771, ranging from 0.688 (FAC-Crav) to 0.765 (BSQ-Rib). The fixation indexes showed positive and significant differences from zero for all sample sets, indicating inbreeding, which may have resulted from the species' mating patterns and the barochoric seed dispersal system of M. nigra. Both markers indicated differentiation among populations, with higher values observed for inter-simple sequence repeat markers. No significant differences between juvenile and adult generations in any of the fragments were observed, indicating the resilience of M. nigra to the effects of fragmentation and reduced habitat.

Diagnostic fingerprints ISSR/SSR for tropical leguminous species Stylosanthes capitata and Stylosanthes macrocephala

“…The SSR/ISSR PCR amplifications were similar to those reported in Moraes Filho et al (2015). Since SSR amplifications with the annealing temperature previously described for these primers (60 °C) only worked in about 47 % of our amplifications, we tested annealing temperatures between 55 and 62 °C.…”

Canopy openness and soil conditions explain community structure and diversity in a tropical seasonal forest in south-eastern Brazil

“…The species is described as a self-incompatible allogamous, pollinated by flies, autochoric, dispersing its seeds via explosive dehiscence (Pombal & Morellato 2000;Schwarcz et al 2010). Its presence can indicate good levels of conservation, because it grows preferably in the shade and innermost preserved regions of the forests (Alzate-Marin et al 2016), and habitat reduction has little effect on the genetic variability of M. nigra, since that larger fragments do not necessarily contain populations with greater genetic diversity (Moraes-Filho et al 2015). Its high abundance in our site suggests that this species can cope with both seasonal climate of semi-deciduous forests, maybe presenting an ability to re-sprout after damage (personal Canopy openness and soil conditions explain community structure and diversity in a tropical seasonal forest in south-eastern Brazil observations), which would be advantageous for understory species (Paciorek et al 2000;Martini et al 2008).…”

Molecular Discrimination for Two Anadenanthera Species of Seasonally Dry Tropical Forest Remnants in Brazil

“…Allemão ex Benth., Fabaceae [27]), and Carrapateira (Metrodorea nigra A. St. Hil., Rutaceae [28]), among many others.…”