First karyotype, DNA C-value and AT/GC base composition of macaw palm (Acrocomia aculeata, Arecaceae) - a promising plant for biodiesel production

The oleaginous species Acrocomia aculeata produces high-quality oil and is considered a potential plant for sustainable production of food and biodiesel. In spite of its economical, social and environmental importance, few data concerning the genome size and chromosomal characterisation of this crop have been reported. In order to contribute to basic genetic knowledge on A. aculeata, this work aimed to assemble the first karyogram and to determine genome size and base composition of this species. Concerning the cytogenetic approach, we developed a protocol based on root tips treatment with an anti-mitotic agent, followed by enzymatic maceration and slide preparation by the air-drying technique. This method provided well resolved metaphasic chromosomes, which are important for an accurate and informative cytogenetical characterisation. A chromosome number of 2n = 30 was observed. Content of 2C DNA and base composition were estimated by flow cytometry of G0/G1 nuclei stained with propidium iodide and 4′,6-diamidino-2-phenylindole, respectively. The mean 2C-value and base composition corresponded to 2C = 5.81 pg and AT = 58.3%. These new data support basic genetic knowledge on A. aculeata, relevant for its conservation, diversity studies and consequent development of breeding programs, which may foment the biofuel production in the world.