Molecular phylogeny of the Pooideae (Poaceae) based on nuclear rDNA (ITS) sequences

Abstract

Phylogenetic relationships of the Poaceae subfamily, Pooideae, were estimated from the sequences of the internal transcribed spacer (ITS) region of nuclear ribosomal DNA. The entire ITS region of 25 species belonging to 19 genera representing seven tribes was directly sequenced from polymerase chain reaction (PCR)-amplified DNA fragments. The published sequence of rice, Oryza saliva, was used as the outgroup. Sequences of these taxa were analyzed with maximum parsimony (PAUP) and the neighbor-joining distance method (NJ). Among the tribes, the Stipeae, Meliceae and Brachypodieae, all with small chromosomes and a basic number more than x=7, diverged in succession. The Poeae, Aveneae, Bromeae and Triticeae, with large chromosomes and a basic number of x=7, form a monophyletic clade. The Poeae and Aveneae are the sister group of the Bromeae and Triticeae. On the ITS tree, the Brachypodieae is distantly related to the Triticeae and Bromeae, which differs from the phylogenies based on restriction-site variation of cpDNA and morphological characters. The phylogenetic relationships of the seven pooid tribes inferred from the ITS sequences are highly concordant with the cytogenetic evidence that the reduction in chromosome number and the increase in chromosome size evolved only once in the pooids and pre-dated the divergence of the Poeae, Aveneae, Bromeae and Triticeae.This paper reports factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also be suitable.

Structural diversity of fructan in relation to the taxonomy of the Poaceae

“…Evidence from both morphological and phylogenetic studies (Clayton & Renvoize, 1986;Soreng, Davis & Doyle, 1990;Watson & Dallwitz, 1992;Davis & Soreng, 1993;Hsiao et al, 1995) separates the tribes Aveneae and Poeae, with good agreement on which genera should be in which tribe. It is therefore likely that evolution of multiple fructan forms within these tribes has occurred independently.…”

Phylogenetic relationships in Carex , subgenus Vignea (Cyperaceae), based on ITS sequences

“…The ITS region (ITS1, 5.8 S, ITS2; about 700 bp) was amplified with the primer pair ITSL (Hsiao et al 1995), ITS5 and ITS4 (White et al 1990) or ITS5i and ITS4i (Roalson et al 2001). PCR was performed as described in Hendrichs et al (2004).…”

Austrostipa, a new genus, and new names for the Australasian species formerly included in Stipa (Gramineae)

“…comm. ) and Hsiao et al (1995) have also been analysing nuclear rDNA (ITS) sequences. As a result of the earlier studies made 68 new combinations in Nassella, and 36 new combinations and one new species in Achnatherum, and five new combinations in Hesperostipa.…”