Species delimitation and hybrid identification of Acrocomia aculeata and A. totai by genetic population approach

Abstract

To the Neotropical genus Acrocomia (Arecaceae) is attributed eight species with a wide distribution in America. A. aculeata and A. totai are the most important species because of their high economic potential for oil production. However, there is no consensus in their classification as different taxons and their distinctiveness is particularly challenging due to morphological similarities with large plasticity of the traits. In addition, there is doubt about the occurrence of interspecific hybrids between both species. In this study, we applied a genetic population approach to assessing the genetic boundaries, diversity and to identify interspecific hybrids of A. aculeata and A. totai. Thirteen loci of simple sequence repeat (SSR) were employed to analyze twelve populations representing a wide distribution of species, from Minas Gerais, Brazil to Formosa, Argentina. Based on the Bayesian analysis (STRUCTURE and NewHybrids) and Discriminant Analysis of Principal Components (DAPC), our study supports the recognition of A. aculeata and A. totai as two species and the estimates of genetic parameters revealed more genetic diversity in A. totai (H E =0.551) than in A. aculeata (H E =0.466). We obtained evidence of hybridization between the species and that admixed individuals were assigned as F2 hybrids. In conclusion, this study showed the usefulness of microsatellite markers to elucidate the genetic boundaries of A. aculeata and A. totai, supporting their classification as different species and increase our knowledge about genetic diversity at the level of populations and species. The results are essentials to establish strategies for the adequate management, conservation, and domestication of both species.

Production of Protein Concentrates from Macauba (Acrocomia aculeata and Acrocomia totai) Kernels by Sieve Fractionation

“…Macauba kernels from A. aculeata [ 15 ] showed contents of albumins, globulins, prolamins, and glutelins of 9.1, 58.5, 9.8, and 22.5% of the total protein extract, respectively. On the other hand, the content of albumins, globulins, prolamins, and glutelins in macauba kernels from the state of Mato Grosso do Sul (western region of Brazil), the same region in which A. totai and its hybrids with A. aculeata are found [ 6 ], was 5.4, 53.5, 1.1, and 40.0%, respectively [ 10 ]. The higher protein solubility, emulsifying activity index, and emulsion stability in the MKM from A. aculeata (HHA 1 ) could, therefore, be related to its higher content of albumins and globulins, whereas the higher content of glutelins could be responsible for the increased water- and oil-binding capacities in the MKM from A. totai (HHT 1 ).…”

“…Among the genus Acrocomia , the species A. aculeata and A. totai present the highest economic relevance, owing to their high oil productivity and multipurpose potential to supply oils, proteins, and fibers [ 6 ]. A. aculeata has a wide geographical distribution, occurring from Mexico to Argentina, and is the most common palm tree in Brazil [ 7 ].…”

“…A. aculeata has a wide geographical distribution, occurring from Mexico to Argentina, and is the most common palm tree in Brazil [ 7 ]. A. totai only occurs in South America, mainly in Bolivia, Paraguay, central-west Brazil, and Northern Argentina [ 6 ]. Differentiation between A. aculeata and A. totai based on genetic, morphological, and biometric characteristics is discussed elsewhere [ 3 , 6 , 8 ].…”

“…A. totai only occurs in South America, mainly in Bolivia, Paraguay, central-west Brazil, and Northern Argentina [ 6 ]. Differentiation between A. aculeata and A. totai based on genetic, morphological, and biometric characteristics is discussed elsewhere [ 3 , 6 , 8 ]. Therefore, understanding the potential of these two species for the production of protein-rich ingredients can provide the framework for their sustainable exploitation.…”