Phylogeny of the parasitic plant family Orobanchaceae inferred from phytochrome A

Abstract

Partial sequences of the nuclear gene encoding the photoreceptor phytochrome A (PHYA) are used to reconstruct relationships within Orobanchaceae, the largest of the parasitic angiosperm families. The monophyly of Orobanchaceae, including nonphotosynthetic holoparasites, hemiparasites, and nonparasitic Lindenbergia is strongly supported. Phytochrome A data resolve six well-supported lineages that contain all of the sampled genera except Brandisia, which is sister to the major radiation of hemiparasites. In contrast to previous plastid and ITS trees, relationships among these major clades also are generally well supported. Thus, the robust phylogenetic hypothesis inferred from the PHYA data provides a much better context in which to evaluate the evolution of parasitism within the group. Ninety-eight species of Orobanchaceae, representing 43 genera, are included and Brandisia, Bungea, Cymbaria, Esterhazya, Nesogenes, Phtheirospermum, Radamaea, Siphonostegia, and Xylocalyx are confirmed as members of Orobanchaceae. The earliest diverging lineage of hemiparasites is identified for the first time; it contains Bungea, Cymbaria, Monochasma, Siphonostegia, and the monotypic Schwalbea, which is federally endangered. This basal clade is marked by the presence of two novel introns. A second, apparently independent gain of one of these introns marks a clade of largely European taxa. There is significant rate heterogeneity among PHYA sequences, and the presence of multiple PHYA in some taxa is consistent with observed ploidy levels.

SEED GERMINATION AND PLANT DEVELOPMENT IN Escobedia grandiflora (OROBANCHACEAE): EVIDENCE OF OBLIGATE HEMIPARASITISM?

“…They are considered either holoparasites or hemiparasites. Holoparasites are almost completely lacking in chlorophyll while hemiparasites have chlorophyll, are photosynthetically active, and derive some resources from their host through haustoria, the organ of parasitism (Yoder, 2001;Watling and Press, 2001;Nickrent, 2002;Bennett and Mathews, 2006). According to the degree of dependence upon host plant(s) for completing the life cycle, root hemiparasitic plants can be facultative or obligate.…”

“…is an American hemiparasitic genus (Bennett and Mathews, 2006;Carranza and Medina, 2008). Two phylogenetic analyses of the family placed this genus in the same clade of obligate parasitic species such as Striga, and as sister to the clade of Melasma P.J.…”

Identification of ISSR Markers for Studying the Biodiversity of Bulgarian Representatives of GenusOrobancheSubsectionMinores

“…Several authors used plastid sequences (4,8,21), nuclear 18S r DnA (4,20), as well as ITS sequences (4,31) to study the phylogeny of this challenging group. Based on the plastid genome sequences there were detected and confirmed the relations between four species of genus Orobanche (32) and were identified four species in subsect.…”

Flora of the cangas of Serra dos Carajás, Pará, Brazil: Orobanchaceae

“…is the largest family among the parasitic angiosperms, comprising ca. 90 genera and over 2000 species of cosmopolitan distribution (Bennett & Mathews 2006). The family presents great morphological diversity, from non-chlorophyllous holoparasites to green photosynthetic hemiparasitic herbs, shrubs or vines (Fischer 2004;Tank et al 2006).…”