The first evidence of a host-to-parasite mitochondrial gene transfer in Orobanchaceae

Several parasitic plants are known to have acquired mitochondrial genes via a horizontal transfer from their hosts. However, mitochondrial gene transfer in this direction has not yet been found in the parasite-rich family Orobanchaceae. Based on a phylogenetic analysis of the mitochondrial atp6 gene in selected species of Orobanche s.l., we provide evidence of a host-to-parasite transfer of this gene in O. coerulescens, which is a Eurasiatic species that parasitises Artemisia (Asteraceae). We did not find the original Orobanche atp6 gene in this species, which suggests that it has been replaced by a gene that was acquired from Asteraceae. In addition, our data suggest the occurrence of a second HGT event in the atp6 sequence - from Asteraceae to Phelipanche. Our results support the view that the transfer of genetic material from hosts to parasites influences the mitochondrial genome evolution in the latter

Phylogeny and historical biogeography analysis support Caucasian and Mediterranean centres of origin of key holoparasitic Orobancheae (Orobanchaceae) lineages

The extensive diversity of the tribe Orobancheae, the most species-rich lineage of holoparasitic Orobanchaceae, is concentrated in the Caucasus and Mediterranean regions of the Old World. This extant diversity has inspired hypotheses that these regions are also centres of origin of its key lineages, however the ability to test hypotheses has been limited by a lack of sampling and phylogenetic information about the species, especially in the Caucasus region. First, we assessed the phylogenetic relationships of several poorly known, problematic, or newly described species and host-races of four genera of Orobancheae occurring in the Caucasus region–Cistanche, Phelypaea, Phelipanche and Orobanche–using nuclear ribosomal (ITS) and plastid (trnL–trnF) sequence data. Then we applied a probablistic dispersal-extinction-cladogenesis model of historical biogeography across a more inclusive clade of holoparasites, to explicitly test hypotheses of Orobancheae diversification and historical biogeography shifts. In sum, we sampled 548 sequences (including 196 newly generated) from 13 genera, 140 species, and 175 taxa across 44 countries. We find that the Western Asia (particularly the Caucasus) and the Mediterranean are the centre of origin for large clades of holoparasitic Orobancheae within the last 6 million years. In the Caucasus, the centres of diversity are composed both of long-branch taxa and shallow, recently diversified clades, while Orobancheae diversity in the Mediterranean appears to represent mainly recent diversification

Achievements in horizontal gene transfer studies in parasitic plants

Horizontal gene transfer (HGT) is a process that allows genetic material to flow between even distantly related organisms. It is primarily observed in bacteria and protists but also in different lineages of eucaryotes. The first HGT cases in plants were discovered at the beginning of the 21st century and have been intensively studied ever since. Researchers have placed particular emphasis on the plant kingdom, especially parasitic plants. This review presents the current state of knowledge about this phenomenon in plants, with a special focus on parasitic plants. Among the described factors facilitating HGT, close physical contact between organisms is believed to be one of the most important. It is noted especially in the case of parasitism and similar relationships. For that reason, reported occurrences of this phenomenon in holoparasites, hemiparasites, and mycoheterotrophic plants are compared. The mechanisms responsible for HGT in plants still remain unclear, however, the studies described here suggest that both DNA and RNA may play a role as a carrier in that process. Also, the transfer between genomes of different organelles in the cell, intracellular gene transfer (IGT), and its relationships with HGT are described. The occurrence of the HGT and IGT phenomena concerning different genomes: nuclear, mitochondrial, and plastid is discussed in the review. Finally, some future areas of research in the field are proposed

Development of a RAPD-based male-specific molecular marker in Japanese hop (Humulus japonicus Siebold & Zucc.)

The male-specific DNA markers are very useful in molecular sexing of non-flowering plants and seeds of dioe- cious species. In this paper we identified ten Y chromosome-specific RAPD primers suitable for identification of male plants in three Cannabaceae species with sex chromosomes (Humulus lupulus, XX/XY; H. japonicus, XX/ XY1Y2; Cannabis sativa, XX/XY). Basing on the nucleotide sequence of the OPJ-09 RAPD product we developed the HJY09 SCAR marker, which is very efficient in sexing of Japanese hop

Orobanche grenieri (Orobanchaceae), a southwestern european species newly found in Asia

We report occurrences of Orobanche grenieri (Orobanchaceae) in the Lesser Caucasus in southern Georgia (western Asia), and in Badakhshan in Tajikistan (central Asia). These localities are more than 3000 and 5000 km apart from its previously known distribution areas in Spain and France, respectively. We used morphological evidence as well as nuclear ribosomal ITS and plastid rbcL sequences to test the taxonomic assignment of the Georgian plants to O. grenieri and to determine their phylogenetic position. We list the features that differentiate O. grenieri from morphologically similar species, provide illustrations, a distribution map, and we propose an IUCN conservation status for the Georgian populations