Filogenia do complexo Caladieae-zomicarpeae (araceae) baseada em seqüências do DNA plastidial
AUTOR(ES)
Adriana Ribeiro Silva Batista
DATA DE PUBLICAÇÃO
2008
RESUMO
The complex Caladieae-Zomicarpeae is composed by the genera Zomicarpa, Zomicarpella, Ulearum, Filarum, Hapaline, Scaphispatha, Caladium, Jasarum, Xanthosoma, Chlorospatha and Syngonium. The complex has an essentially Neotropical distribution, with the sole exception of the Asian genera Hapaline. The group contains elements of moderate economic importance, as ornamental species (Caladium and Syngonium), or food crops (Xanthosoma), but its taxonomy still is confused. The accepted classification divides complex in two distinct tribes: Caladieae and Zomicarpeae. However, the circumscription of the tribes of the complex is problematic, as well as circumscription of each involved genera. Xanthosoma is considered a promising as food source in developing countries, but programs of genetic improvement are now impossible because of the absence of basic knowledge about evolution and relationships between the cultivated species and its wild relatives. Moreover the generic limits between Xanthosoma, Caladium and Chlorospatha remaed in debate more how to thirty years. We used nucleotide sequences of the markers matK, íntron trnK and the spacer trnL-trnF . We analyzed 58 accessions, three of hiem outgroups (Amorphophallus bulbifer, Typhonium roxburghii and Orontium aquaticum). We used two phylogenetic approaches: Maximum Parsimony and Bayesiana Inference, essentially with similar results. Our results indicate that the Caladieae-Zomicarpeae complex is paraphyletic. Moreover, elements of both tribes appeared interleaved in the cladogram. This suggests that the tribe Caladieae should be expanded to include the genera of the tribe Zomicarpea. The genera Xanthosoma and Chlorospatha are not monophyletic groups if taken separately, but formed a well-supported clade together. Such result suggests that the shared aspect of the grain of pollen in tetrads has only appeared a time in the complex. The similarities between Caladium and Xanthosoma seem to have appeared for convergent evolution since the clades for these groups had are clearly independent. Moreover our results point to a relatively recent origin of the majority of the cultivated species of Xanthosoma and should be of relocate programs of genetic improvement. Caladium lindenii, a widely cultivated species of the group, appeared as distinct from the other supposedly congeneric species, nesting in the same clade as analyzed species of Syngonium. Scaphispatha seem to be inseparable from Caladium in our analyses. Our results can contribute with important guidelines in the elaboration of classification system for the Caladieae-Zomicarpeae complex, indicating the need for redefinition of the tribal concept and adjustments in the circumscription of genera, including an expansion of Xanthosoma to include Chlorospatha.
ASSUNTO(S)
plantas - filogenia botânica botânica; plantas - filogenia botany anatomia vegetal plants - filogenia
