Characterization of the complete plastid genome of Butia eriospatha (Arecaceae)

Abstract

Butia eriospatha is an endemic palm species from the Atlantic Rainforest in Brazil, a biodiversity hotspot. This species is currently listed in the IUCN red list as vulnerable and lacks specific plastid markers for population genetics studies. In addition, the evolutionary relationship within the genus Butia is not yet well resolved. Here, we sequenced and characterized the complete plastid genome (plastome) sequence of B. eriospatha. The complete plastome sequence is 154,048 bp in length, with the typical quadripartite structure. This plastome length and genes content is consistent with other six species from tribe Cocoseae. However, the Inverted Repeat (IR) borders show some variation among the analyzed species from this tribe. Species from the Bactridinae (Astrocaryum and Acrocomia) and Elaeidinae (Elaeis) subtribes present the rps19 gene completely duplicated in the IR region. In contrast, all plastomes sequenced from the subtribe Attaleinae (Butia, Cocos, Syagrus) present one complete CDS of rps19 and one partial copy of rps19. The difference in the IR/LSC junctions between Attaleinae and the sister clades Bactridinae + Elaeidinae might be considered an evolutionary signal and the plastome sequence of B. eriopatha may be used in future studies of population genetics and phylogeny.

Figure 1. Graphical map of Butia eriospatha plastid genome. Genes shown on the outside of the circle are transcribed clockwise; genes on the inside are transcribed counterclockwise. Genes were grouped and represented by different colors according their function group. The GC content is represented by the dashed darker grey area in the inner circle, the lighter grey area represents AT content.

Figure 2. Comparison of plastid genome LSC, IR, and SSC junction positions within the tribe Cocoseae (Arecaceae: Arecoideae). Genes shown below are transcribed counterclockwise and those shown above the lines are transcribed clockwise.