Publications by authors named "Daniel L Nickrent"

Article Synopsis
  • The study investigates how haustorial parasitism affects the plastid genome, particularly within the Santalales order, by comparing non-parasitic and hemiparasitic plant families to understand the transition to a parasitic lifestyle.
  • Researchers sequenced and analyzed new samples' plastomes and nuclear ribosomal genes to explore phylogenetic relationships and evolution patterns in plastid genes.
  • Findings revealed significant genetic changes, including a complete loss of certain plastid genes in confirmed parasites, suggesting a link between plastome evolution and the shift toward parasitism.
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Several molecular phylogenetic studies of the mistletoe family Loranthaceae have been published such that now the general pattern of relationships among the genera and their biogeographic histories are understood. Less is known about species relationships in the larger (> 10 species) genera. This study examines the taxonomically difficult genus Taxillus composed of 35-40 Asian species.

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A new holomycoheterotrophic member of Burmanniaceae, , is described from Mt. Hamiguitan located on the island of Mindanao, Philippines. This species differs from the recently named from Cebu in a number of quantitative and qualitative characters.

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Rafflesia (Rafflesiaceae) is a small endo-holoparasitic Asian plant genus known for its exceptionally large flowers, rare species, and high island endemism. In this study, phylogenetic (parsimony and Bayesian inference) and biogeographic (BioGeoBEARS) analyses of DNA sequence data (atp6 and matR genes, and nad1 B-C intron from the mitochondrial genome, and the nuclear ribosomal internal transcribed spacer) were used to reconstruct the phylogenetic relationships among 12 of the 13 known Philippine Rafflesia species and to determine the timing and pathways of their diversification. The results of these analyses confirm those of previous Rafflesia studies (which were largely focused on non-Philippine species) in finding pronounced biogeographic patterns.

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Premise Of The Study: The sandalwood order (Santalales) includes members that present a diverse array of inflorescence types, some of which are unique among angiosperms. This diversity presents not only interpretational challenges but also opportunities to test fundamental concepts in plant morphology. Here we used modern phylogenetic approaches to address the evolution of inflorescences in the sandalwood order.

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Besides their alleged therapeutic effects, mistletoes of the genus Viscum L. (Viscaceae) are keystone species in many ecosystems across Europe, Africa, Asia and Australia because of their complex faunal interactions. We here reconstructed the evolutionary history of Viscum based on plastid and nuclear DNA sequence data.

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Coadaptation between mistletoes and birds captured the attention of Charles Darwin over 150 years ago, stimulating considerable scientific research. Here we used Loranthaceae, a speciose and ecologically important mistletoe family, to obtain new insights into the interrelationships among its hosts and dispersers. Phylogenetic analyses of Loranthaceae were based on a dataset of nuclear and chloroplast DNA sequences.

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All around the globe, humans have greatly altered the abiotic and biotic environment with ever-increasing speed. One defining feature of the Anthropocene epoch is the erosion of biogeographical barriers by human-mediated dispersal of species into new regions, where they can naturalize and cause ecological, economic and social damage. So far, no comprehensive analysis of the global accumulation and exchange of alien plant species between continents has been performed, primarily because of a lack of data.

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Santalales comprise mainly parasitic plants including mistletoes and sandalwoods. Bitegmic ovules similar to those found in most other angiosperms are seen in many members of the order, but other members exhibit evolutionary reductions to the unitegmic and ategmic conditions. In some mistletoes, extreme reduction has resulted in the absence of emergent ovules such that embryo sacs appear to remain embedded in placental tissues.

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The mistletoe Tristerix corymbosus (Loranthaceae) is present in the temperate forest and Chilean matorral biomes of Chile and northwest Patagonia. The closely related cactus-specific species, T. aphyllus, occurs only in the matorral biome.

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Extreme modification and reduction in floral morphology presents an obstacle to determining the evolutionary relationships and homologies of the holoparasites in Balanophoraceae. Developing flowers and inflorescences of two dioecious species, Balanophora papuana and B. elongata, were compared to each other and to the monoecious B.

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Chloroplast sequences spanning rps7 to 23S rDNA in Arceuthobium campylopodum and A. pendens were generated and compared to Arabidopsis and seven other parasitic plants. Pseudogenes for trnV, trnI (GAU), and trnA (UGC) were seen in both Arceuthobium species, paralleling the situation in the holoparasite Epifagus (Orobanchaceae).

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Loranthaceae (73 genera and ca. 900 species) comprise mostly aerial hemiparasitic plants. Three monotypic genera considered relicts are root parasites.

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Past molecular phylogenetic work has shown that aerial parasites have evolved five times independently in the sandalwood order (Santalales), but the absolute timing of these diversifications was not addressed. DNA sequences from nuclear SSU and LSU rDNA, and chloroplast rbcL, matK and trnL-F from 39 santalalean taxa were obtained. Separate and combined data partitions were analyzed with maximum parsimony and Bayesian inference.

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Phylogenies can provide valuable information on biotic and abiotic factors associated with speciation. We examined species relationships in Tristerix (Loranthaceae), a genus of 11 species with an Andean distribution from Colombia to Chile. A previous classification divided Tristerix into subgenera Tristerix (two species) and Metastachys (nine species).

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Species of Rafflesiaceae possess the world's largest flowers (up to 1 meter in diameter), yet their precise evolutionary relationships have been elusive, hindering our understanding of the evolution of their extraordinary reproductive morphology. We present results of phylogenetic analyses of mitochondrial, nuclear, and plastid data showing that Rafflesiaceae are derived from within Euphorbiaceae, the spurge family. Most euphorbs produce minute flowers, suggesting that the enormous flowers of Rafflesiaceae evolved from ancestors with tiny flowers.

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Background: Although recent molecular phylogenetic studies have identified the photosynthetic relatives of several enigmatic holoparasitic angiosperms, uncertainty remains for the last parasitic plant order, Balanophorales, often considered to include two families, Balanophoraceae and Cynomoriaceae. The nonphotosynthetic (holoparasitic) flowering plant Cynomorium coccineum has long been known to the Muslim world as "tarthuth" and to Europeans as the "Maltese mushroom"; C. songaricum is known in Chinese medicine as "suo yang.

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Background: The phylogenetic relationships among the holoparasites of Rafflesiales have remained enigmatic for over a century. Recent molecular phylogenetic studies using the mitochondrial matR gene placed Rafflesia, Rhizanthes and Sapria (Rafflesiaceae s. str.

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Ribosomal genes are considered to have a high degree of sequence conservation between species and also at higher taxonomic levels. In this paper we document a case where a single individual of Cynomorium coccineum (Cynomoriaceae), a nonphotosynthetic holoparasitic plant, contains highly divergent plastid ribosomal genes. PCR amplification a nearly complete ribosomal DNA cistron was performed using genomic DNA, the products cloned, and the 23S rDNA genes were sequenced from 19 colonies.

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The genus Arceuthobium (dwarf mistletoes, Viscaceae) comprises 42 species that parasitize hosts in Pinaceae and Cupressaceae in the Old and New Worlds. Maximum parsimony analyses were conducted on two data partitions (separately and combined): nuclear ribosomal internal transcribed spacer (ITS) sequences for all 42 currently recognized species and chloroplast trnT-L-F sequences for 34 New World species. The Old and New World species were phylogenetically distinct using ITS, thus making subgenus Arceuthobium paraphyletic.

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Utilization of molecular phylogenetic information over the past decade has resulted in clarification of the position of most angiosperms. In contrast, the position of the holoparasitic family Hydnoraceae has remained controversial. To address the question of phylogenetic position of Hydnoraceae among angiosperms, nuclear SSU and LSU rDNA and mitochondrial atp1 and matR sequences were obtained for Hydnora and Prosopanche.

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