Maytenus ilicifolia (Celastraceae) is a medicinal plant that is native to southern Brazil and is popularly known as “espinheira-santa”. From a biosynthesis perspective, this species accumulates quinonemethide triterpenes and sesquiterpene pyridine alkaloids as major secondary metabolites that exhibit interesting biological properties, with antitumoral and antiprotozoal activities, respectively, being the most frequently reported. Additionally, the restricted accumulation of such compounds in the roots raises questions about the expression of proteins involved in such compartmentalization and their possible biological and/or ecological role in M. ilicifolia. Thus, this article describes the use of shotgun proteomics and histochemical studies for the characterization of the main biosynthetic pathways involved in the regulation of the metabolism in M. ilicifolia roots. This combined approaches also resulted in the identification of a series of proteins involved in the quinonemethide triterpenes and sesquiterpene pyridine alkaloids, providing evidences of their differential compartmentalization.

O gênero Dahlstedtia, segundo alguns autores, é representado por duas espécies; para outros, é considerado monotípico. Este estudo confirma o primeiro posicionamento. As espécies ocorrem preferencialmente na Floresta Atlântica brasileira: D. pinnata nos estados do RJ e SP e D. pentaphylla em SP, PR e SC, não tendo sido observada sobreposição geográfica. Em polinizações interespecíficas, a fertilização em D. pinnata foi evitada pela presença de uma secreção densa na micrópila. D. pentaphylla e D. pinnata provavelmente não trocam pólen na natureza e, caso ocorresse polinização interespecífica, não haveria formação de sementes. Apesar das semelhanças existentes entre as espécies, confirma-se a posição taxonômica adotada por Burkart, na qual Dahlstedtia é constituído por pelo menos duas espécies: D. pinnata e D. pentaphylla.

Dahlstedtia has been considered a monotypic genus by some authors, but comprising two species according to others. The latter view was supported by our biosystematic study. The two species are Neotropical, mainly occurring in the Brazilian Atlantic Forest, where they are, however, allopatric. Experimental pollinations show that the two species are intersterile. After interspecificcrossings, few pollen tubes reach the ovule, a dense secretion fills the micropyle and no proembryos are formed. Probably, there is no gene flow between species, but if it should occur, no hybrids would be formed. The present work confirms Burkart's taxonomic view, according to which Dahlstedtia comprises at least two species: D. pinnata and D. pentaphylla.