The cultivation of forage cactus is of great economic interest in Brazil, due to its then importance for nutrition animal. This crop had been studied for many years but the advent of molecular biology has greatly contributed to shed light on its phylogeny. Twenty-eight prickly pear cactus plants (Opuntia and Nopalea) - from Brazil were analyzed using the ribosomal marker ITS (internal transcribed space regions) of rRNA ribosomal gene. Three prickly pear cactus varieties are used the forage in Northeastern Brazil: var. palma gigante (Opuntia ficus-indica), var. palma redonda (Opuntia sp.), var. miúda (Nopalea cochenillifera or Opuntia cochenillifera). The DNA was extracted from leaves and the ITS1 and ITS2 regions of all plants amplified and sequenced. Results showed que the ITS marker is very efficient to investigate the species studied and examine the level of the genus cactus plants. Interestingly, the species Nopalea cochenillifera when submitted to the NCBI its designation was changed to Opuntia cochenillifera, however, the organisms continues the Nopalea cochenillifera. These plants may show high degree of apomixis, vegetative propagation, ploidy and the high inter and intraspecific hybridization capacity. Plant systematic and phylogenetic studies are based on morphological and molecular mainly characteristics. The ribosomal ITS rRNA markers 1-2 have great ability to characterize species of prickly pear cactus in this work. Additional studies with other phylogenetic markers will deepen the understanding of the phylogeny of these species.
Key words: Cactaceae, tropical plants, Nopalea, Opuntia, Taxonomy, ITS.
|
