Citogenética, palinologia e genética molecular in silico da tribo Ingeae Benth. (Leguminosae Adans.)

Abstract

The Mimosoid clade currently belongs to the subfamily Caesalpinioideae and family Leguminosae (formerly Fabaceae), which presents approximately 770 genera and 19,500 species, being the third largest family of phanerogams. The objective of the work was to perform the chromosomal and palynological characterization of representatives of the Ingeae tribe and situate them in an evolutionary context through a comparative cytogenetic reconstruction. In this work, pollen characteristics of 60 species of thirteen genera of Clad Mimosoid and 54 species in the reconstruction of the ancestral chromosome number were analyzed. For the pollen analysis the floral material was hydrated by the technique of acetolysis, and subsequently measured, described, photomicrographs under an optical microscope (M.O.). Quantitative data were submitted to descriptive statistical treatment. For cytogenetic characterization, placement techniques were used with CMA and DAPI fluorochromes and phylogenetic analysis by Bayesian inference in which it was used to reconstruct the ancestral chromosome number by ChromEvol. In the pollen analysis the presence of pollen agglomerates between the species ranging from 16, 20, 24, 28 and 32 pollen grains constituting the different dispersion units was confirmed, resulting in heterogeneity both among the genera and in the same genus. It was possible to characterize and differentiate many species through quantitative and qualitative data by the number of pollen grains per unit of dispersion, shape, symmetry and size of poles. The data obtained was useful to differentiate and corroborate in the classification of most of the different taxa and in taxonomy studies of this tribe. The chromosomal characterization showed that the number and distribution pattern of the CMA + bands were different among the Calliandra species in the Androcallis section, with even more bands than the Microcallis section. Essentially in the Androcallis section the number of CMA + bands was not associated with the level of ploidy. Signs of inversion were observed in some species. Reconstruction indicates that the ancestral chromosome number for the Ingeae tribe is n = 13. The Calliandra genus presented an ancestral number n = 8. The most frequent event was the chromosomal gain, however, the duplication presented the highest net balance of diversification.