Molecular Phylogenetics of Bromus (Poaceae: Pooideae) Based on Chloroplast and Nuclear DNA Sequence Data

Abstract

We conducted a phylogenetic analysis to characterize relationships among Bromus and test the monophyly of five of the seven morphologically distinct groups within Bromus (Poaceae: Pooideae) that have been treated as sections, subgenera, or genera. We sequenced the chloroplast trnL (UAA) intron, the 3Ј-end of the chloroplast ndhF gene, and the internal transcribed spacers (ITS) of the nuclear ribosomal DNA region for 46 species that represent a large proportion of the morphological and geographical diversity in the genus. Independent analyses of plastid and nuclear ribosomal data identified several lineages in Bromus, but there is some evidence of incongruence between these linkage groups. Nuclear ribosomal trees indicate that two clades comprising some North and South American species of sect. Bromopsis are the successive sister groups of the rest of the genus, and that Old World species of sect. Bromopsis are more closely related to sects. Ceratochloa and Neobromus than they are to the remaining North American species of sect. Bromopsis. In contrast, plastid trees indicate a close relationship between Old World and some North American species of sect. Bromopsis. In the nuclear ribosomal trees, sects. Genea and Bromus (if sect. Triniusia is included within it, as treated by most authors) are monophyletic and not closely related. In the plastid trees, species of these two sections are intermixed, supporting a hybrid origin for B. pectinatus. The monophyly of sect. Ceratochloa is supported in the plastid and nuclear ribosomal trees, and the monophyly of sect. Neobromus is robustly supported in the nuclear ribosomal trees. Current classification schemes do not reflect phylogenetic relationships in Bromus. Tentative evidence of conflict among nuclear and plastid data partitions needs clarification with more robustly supported plastid and nuclear ribosomal gene trees.

A Preliminary Phylogenetic Analysis of the Grass Subfamily Pooideae (Poaceae), with Attention to Structural Features of the Plastid and Nuclear Genomes, Including an Intron Loss in GBSSI

“…as sister of Bromus L. plus Triticeae. A similar result is reported by Saarela et al (2007), whose sampling within Bromeae is broader than that of the present analysis; Littledalea was not sampled by Soreng and Davis (2000). A critical difference between the results of the present analysis and those of Soreng and Davis (2000) lies in the placement of Brachypodieae (represented by Brachypodium), rather than a clade consisting of Brachypodieae plus Meliceae, as sister of the BT/P clade.…”

Regional variation in Argentinean populations of <i>Bromus catharticus</i> (Poaceae) as measured by morphological

“…Bromus L. is a taxonomically difficult genus with a wide distribution (> 150 species) over temperate regions of both hemispheres (Clayton & Renvoize, 1986;Saarela & al., 2007 B. valdivianus).…”

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“…(Sljussarenko, 1977). У номенклатурному зведенні для території України (Bor, 1970;Scholz, 1981;Smith, 1985;Matthei, 1986;Sales, 1993;Petrova, Kožuharov, Ehrendorfer, 1997;Saarela et al, 2007Saarela et al, , 2014, рідше -роду (Tzvelev, 1976(Tzvelev, , 2006Sljussarenko, 1977;Shaw, Montgomery, 2011;Weber, Wittmann, 2011). У цій статті ми розглядаємо рід Bromus у широкому розумінні; на правах секцій до нього включаємо групи, що виділялися як роди Bromus s.…”

“…У цій статті ми розглядаємо рід Bromus у широкому розумінні; на правах секцій до нього включаємо групи, що виділялися як роди Bromus s. str., Bromopsis, Anisantha й Ceratochloa, що узгоджується з сучасною системою триби Bromeae (Saarela et al, 2007).…”