Coffea spp. chromosomes are very small and accumulate a variety of repetitive DNA families around centromeres. However, proximal regions of Coffea chromosomes remain poorly understood, especially on the nature and organisation of the sequences. Taking advantage of genome sequences of C. arabica (2n = 44), C. canephora, and C. eugenioides (C. arabica progenitors with 2n = 22) and good coverage genome sequencing of dozens of other wild Coffea spp., repetitive DNA sequences were identified, and the genomes were compared to decipher particularities of pericentromeric structures. The searches revealed a short tandem repeat (82 bp length) typical of Gypsy/TAT LTR retrotransposons, named Coffea_sat11. This repeat organises clusters with fragments of other transposable elements, comprising regions of non-coding RNA production. Cytogenomic analyses showed that Coffea_sat11 extend from pericentromeres towards the middle of the chromosomal arms. This arrangement was observed in the allotetraploid C. arabica chromosomes, as well as in its progenitors. This study improve our understanding of the role of Gypsy/TAT LTR retrotransposon lineage in the organization of Coffea pericentromeres, as well as the conservation of Coffea_sat11 within the genus. The relationships with fragments of other transposable elements and the functional aspects of these sequences on the pericentromere chromatin were also evaluated.

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Passiflora coelestis is morphologically and anatomically described from living material as a new species belonging to the section Dysosmia, supersection Stipulata and subgenus and genus Passiflora. The species occurs in Araucaria Moist Forest, a phytophysiognomy of the Atlantic Forest biome. The section has been characterized as one of the most taxonomically complex groups within Passiflora. Passiflora coelestis is related to species within the Dysosmioides group and is similar to P. campanulata, differing mainly in the stipules, petiole, bracts, and corona filaments. The new species is morphologically compared with taxa of the section; moreover, additional anatomic, palynological and molecular data are also discussed with regard to taxonomic classification.

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Cestrum species present large genomes (~24 pg), a high occurrence of B chromosomes, and great diversity in heterochromatin bands. Despite this, there is maintenance of chromosome shape and karyotype symmetry. To deepen our knowledge on Cestrum genome composition, low coverage sequencing data of C. strigilatum and C. elegans were compared. Bioinformatics analyses showed retrotransposons comprising more than 70% of the repetitive fraction, followed by transposons (~18%). The four satDNA families that accumulated the most in the datasets were used as probes in FISH assays, and showed different distribution profiles along chromosomes. Most hybridization signals were located in the C-CMA/DAPI banding sites, including those related to AT-rich Cold-Sensitive Regions (CSRs) and heterochromatin. Although satellite probes hybridized in all tested species, a satDNA family named CsSat49 was highlighted as it predominates in centromeric regions. Data suggest that the satDNA fraction is still conserved in the genus, although there is variation in the number of FISH signals between karyotypes, as well as in the B chromosomes. This study brings an important advance in the knowledge on genome organization and heterochromatin composition in Cestrum, especially on the distribution and differentiation mechanisms of satellite fraction between species of a genus of Solanaceae with large genomes.

Tapetal cells comprise an anther tissue fundamental to pollen grain development. They are associated with endoreduplication events, which culminate in polyploid and multinucleated cells, high metabolic activity, and different organelle arrangements to support all the development of the pollen grains. Passiflora species present a secretory tapetum, with diversity in the number and size of nuclei. Tapetal cells undergo numerous changes in a short period of development when compared to the plant's life span. To improve our knowledge of tapetum development, tests assessing ploidy levels, anatomy, cytochemistry, transmission electron microscopy, flow cytometry, as well as conventional and molecular cytogenetics were used in Passiflora actinia and P. elegans. The current data show striking differences in nuclear organisation during tapetal cell development, including mono to quadrinucleate cells, and ploidy levels from 2n to 32n. One of the most peculiar features was the atypical behaviour of the endoplasmic reticulum (ER), which accumulated in the cell border, similar to a ‘cER’, as well as large dictyosomes. This endomembrane configuration may be related to the tapetum nutritional network and secretion of compounds at the end of meiosis. Another atypical feature of the ER was the formation of an invagination to establish ‘binucleated’ polyploid cells. This membrane projection appears when the nuclei form two lobes, as well as when it organises a nucleoplasmic reticulum. These data demonstrate that there are important ultrastructural changes in tapetal cells, including organelle arrangements, ploidy levels, and nuclear activity, common to P. actinia and P. elegans, but different from the plant model A. thaliana.