Contrasting Levels of Genetic Diversity Among Populations of the Endangered Tropical Palm Euterpe Edulis Martius

Abstract

ABSTRACT:Euterpe edulis is a tropical species that produces the heart of palm, an edible product of high economic importance. However, its natural populations have been severely threatened by unrestricted exploitation, along with the destruction of its natural biome, the Atlantic Rainforest in Brazil. In this work, we examined the genetic diversity status of five natural populations using isozyme markers. Despite their limitations and replacement by DNA-based markers, isozymes are codominant markers that reveal accurate estimates of genetic diversity and structure patterns, as do microsatellites. Six informative isozyme markers were used to analyze the genetic variability of populations located in different areas of the Atlantic Forest (Ombrophilous Dense Forest and Seasonal Forest), and with different degrees of perturbation. Mean genetic diversity for all populations (H o = 0.172, for 13 loci) was considered low for a tropical species, even for the markers used. Populations from Ombrophilous Dense Forest at the very South limit of distribution of the heart of palm presented the lowest genetic variability (H o = 0.141), which is clearly observed from the allele frequencies, and might implicate in less adaptive potential in a scenario of climate change. On the contrary, the Seasonal Forest population presented the highest diversity (H o = 0.237). It comprises one of the largest remaining reservoirs of heart of palm and maybe of its genetic variability. The contrasting levels of genetic diversity encountered in this study rehash the constant need of monitoring and conserving the current genetic diversity of E. edulis populations, as well as exploring strategies for its breeding. NÍVEIS DE DIVERSIDADE GENÉTICA CONTRASTANTES ENTRE POPULAÇÕES DE EUTERPE EDULIS MARTIUS, PALMEIRA TROPICAL AMEAÇADARESUMO: Euterpe edulis é uma espécie tropical que produz o palmito, produto comestível de elevada importância econômica. No entanto, as populações naturais da espécie têm sido severamente ameaçadas devido à exploração indiscriminada, conjuntamente com a destruição de seu bioma natural, a Mata Atlântica. Apesar de suas limitações e substituição por marcadores de DNA, isoenzimas são marcadores codominantes que permitem obter estimativas acuradas dos padrões de diversidade e estrutura genética, assim como microssatélites. Seis marcadores isoenzimáticos foram utilizados para analisar a variabilidade de populações localizadas em diferentes áreas da Mata Atlântica (Floresta Ombrófila Densa e Floresta Estacional), e com diferentes níveis de perturbação. A diversidade genética média de todas as populações (Ho = 0,172, para 13 locos) foi considerada reduzida para uma espécie tropical, até mesmo para os marcadores empregados. Populações da Floresta Ombrófila Densa no limite sul de distribuição do palmiteiro apresentaram a diversidade genética mais reduzida (Ho = 0,141), o que é claramente observado a partir de perfis de peroxidase, e pode implicar em menor potencial adaptativo em um cenário de mudança climática. Contrariamente, a popul...

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