INVESTIGADORES
GIUSSANI Liliana Monica
congresos y reuniones científicas
Título:
Phylogenetic structure in the large genus Poa
Autor/es:
SORENG, RJ1, GILLESPIE, LJ2, GIUSSANI, LM3, SCATAGLINI,
Lugar:
Melbourne
Reunión:
Congreso; XVIII International Botanical Congress; 2011
Institución organizadora:
International Union of Biological Sciences (IUBS),
Resumen:
A phylogenetic analysis of Poa (over 500 spp.) using an expanded sample of species from around the world (269 spp. and an additional 39 infraspecies), with more complete sampling for plastid trn TLF region and nrDNA spacer regions ITS and ETS than previous studies, revealed two large derived clades (number of species based on morphology) Poa-Homalopoa (360 spp.) and subgen. Stenopoa (85 spp.) that contain most of the species in the genus.  The subgen. Ochlopoa clade contains a further 36 spp., subgen. Pseudopoa (Eremopoa) 5 spp., subgen. Sylvestres 8 spp., and sect. Pandemos 2 spp. The small clade including sect. Nanopoa had 3 species confined to it, and 11 that share plastid types with it, including all species of sects. Secundae, and some of sects. Cenisiae s.s. and Bolbophorum: Secundae and Cenisiae share ITS-ETS types with the Stenopoa clade. Poa bulbosa of sect. Bolbophorum has plastid/nrDNA combinations of either the clade with Nanopoa or the clade with consectional species of in the Ochlopoa clade, but not intermixed types.   An odd and strongly supported nrDNA ITS-ETS “X-clade”, for which no corresponding plastid clade has been identified, appeared in 40 species from around the Pacific basin (China, Hawaii, Japan, New Guinea, New Zealand, North and South America: including sects.  Acroleucae, Malacanthae, Siphonocoleus, and elements of Orienos, Pauciflorae, and about 2/3 of New Zealand spp.). Plastid sequences of species with X-type nrDNA mostly resolved in the Poa- Homalopoa clade, but 4 spp. aligned with sects. Orienos and Pauciflorae.  Based on DNA studies Poa is considered to include the genera Anthochloa, Aphanelytrum, Austrofestuca s.s., Dissanthelium, Eremopoa, Parodiochloa, Tovarochloa, Tzvelevia; exclude the more recently described genera Arctopoa, Nicoraepoa, Saxipoa, Sylvipoa; and to have reticulate relationships with Aniselytron, Arctopoa, Nicoraepoa, and possibly Hyalopoa.