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Rafflesia produces the largest single flowers in the world, at the expense of its host vine, Tetrastigma, yet it begins as an inconspicuous endophyte. It is unknown how the Rafflesia seed gets into the host and germinates. Multiple locals claim to have successfully grown the holoparasitic flower from seeds resulting in blooms. Using available morpho-histological studies, combined with descriptions from local Rafflesia seed growers, as well as unpublished details of our own work, we filled in the missing details of Rafflesia's life cycle from seed germination to endophyte inside the host before it transitions to its flowering stage. Post-germination, the Rafflesia endophyte forms a clonal network of vegetative meristematic cells, separated by the dividing host tissue, each meristematic cell cluster eventually developing into the primordial floral bud or protocorm. We propose future work involving mass spectrometry imaging to characterize the metabolites that allow communication between distant endophytic clusters and floral bud induction without destroying the histology of the sample. Keywords Rafflesiaceae * Holoparasite * Parasitic plant * Plant development, Introduction Rafflesia produces the largest single flowers in the world, growing up to a meter in diameter, at the expense of its host plant, Tetrastigma (Vitaceae). Restricted to the fast [...]

Rafflesia is an endangered endophytic holoparasitic plant that lives the majority of its life inside the tissues of its sole plant host, Tetrastigma. Rafflesia floral buds emerge to produce the world's largest single flower. Like other plants, holoparasites harbor a diverse microbiome, the role(s) of which has remained largely unstudied. We characterized the bacterial microbiome of seeds of Rafflesia speciosa and cuttings of its host. We found evidence that R. speciosa seed has similar bacterial profiles to its infected host, which suggests that seeds sequester certain host bacteria, as well as acquire unique bacterial taxa from biotic associates of the fruit. We did not find evidence of mycorrhizal taxa in the microbiome. This is the first study of the microbial endophytes associated with any Rafflesia species and its host, a tripartite holobiont, and provides insights on its cryptic microbial partners. We discuss how this may aid horticultural propagation of Rafflesia. [ABSTRACT FROM AUTHOR]

Oryza sativa or Asian cultivated rice is one of the major cereal grass species domesticated for human food use during the Neolithic. Domestication of this species from the wild grass Oryza rufipogon was accompanied by changes in several traits, including seed shattering, percent seed set, tillering, grain weight, and flowering time. Quantitative trait locus (QTL) mapping has identified three genomic regions in chromosome 3 that appear to be associated with these traits. We would like to study whether these regions show signatures of selection and whether the same genetic basis underlies the domestication of different rice varieties. Fragments of 88 genes spanning these three genomic regions were sequenced from multiple accessions of two major varietal groups in O. sativa--indica and tropical japonica--as well as the ancestral wild rice species O. rufipogon. In tropical japonica, the levels of nucleotide variation in these three QTL regions are significantly lower compared to genome-wide levels, and coalescent simulations based on a complex demographic model of rice domestication indicate that these patterns are consistent with selection. In contrast, there is no significant reduction in nucleotide diversity in the homologous regions in indica rice. These results suggest that there are differences in the genetic and selective basis for domestication between these two Asian rice varietal groups.

Herbal medicinal products (HMPs) have grown increasingly popular in the United States, many of them with imported raw materials and sold online. Yet due to the lack of regulation from the US Food and Drug Administration (FDA), manufacturers of the products can substitute or add in other herbs that are not advertised on the label. In this study, as part of the Urban Barcode Research Program (UBRP), an education initiative to engage New York City high school students in science, we aimed to taxonomically authenticate single-ingredient online-sold HMPs containing non-native plants through DNA barcoding of the internal transcribed spacer 2 region (ITS2) and matK. We were able to successfully barcode 20 HMPs, but four of these did not match the expected species. It was concluded that the four HMPs advertising astragalus, epazote, ginseng, and chanca piedra were contaminated/ substituted because their ITS2 and matK DNA sequences did not match the expected taxonomy in GenBank, a government database. Our study highlights the importance of herbal pharmacovigilance in the absence of strict government regulation of herbal supplements and motivates crowd-sourced DNA barcoding to enable American consumers make informed choices and be more empowered to safeguard their health.

Leea, sometimes treated as the monogeneric family Leeaceae, is sister to the rest of the grape family, Vitaceae, but its systematics is poorly known. Phylogenetic relationships in Leea were reconstructed with parsimony and Bayesian methods using nuclear ribosomal sequences to assess species circumscriptions, morphological evolution and biogeography. The internal transcribed spacer secondary structure model for Leea facilitated homology assessments during sequence alignment. Nine morphological characters were mapped onto the phylogenetic tree. Four major clades in Leea were supported, with L. asiatica s.l. (=clade I) as the earliest diverging clade and having plesiomorphic free stamens. Clade II, which includes the prickle-bearing species, is sister to clade III, which includes species with comparatively large flowers. Clade IV, sister to clade II + III, was resolved into four subclades. Each subclade included accessions of L. indica and L. guineensis intermixed with six other morphologically distinct species, showing the polyphyly of these two species as currently circumscribed. Flower colour, previously used to characterize species, was shown to be unreliable for species identification. Dating analyses estimated that Leea originated in Indochina in the Late Cretaceous (65-86.19 Mya, 95% highest posterior density). The members of the major clades later spread to India, Africa, Madagascar, South-East (SE) Asia and tropical Australasia. Major species diversification occurred in the Neogene, when dynamic environmental and geological changes in SE Asia presented new ecological niches. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, ●●, ●●-●●. [ABSTRACT FROM AUTHOR]

Oryza sativa or Asian cultivated rice is one of the major cereal grass species domesticated for human food use during the Neolithic. Domestication of this species from the wild grass Oryza rufipogon was accompanied by changes in several traits, including seed shattering, percent seed set, tillering, grain weight, and flowering time. Quantitative trait locus (QTL) mapping has identified three genomic regions in chromosome 3 that appear to be associated with these traits. We would like to study whether these regions show signatures of selection and whether the same genetic basis underlies the domestication of different rice varieties. Fragments of 88 genes spanning these three genomic regions were sequenced from multiple accessions of two major varietal groups in O. sativa--indica and tropical japonica--as well as the ancestral wild rice species O. rufipogon. In tropical japonica, the levels of nucleotide variation in these three QTL regions are significantly lower compared to genome-wide levels, and coalescent simulations based on a complex demographic model of rice domestication indicate that these patterns are consistent with selection. In contrast, there is no significant reduction in nucleotide diversity in the homologous regions in indica rice. These results suggest that there are differences in the genetic and selective basis for domestication between these two Asian rice varietal groups. [ABSTRACT FROM AUTHOR]

The article presents a study that assesses the utility of secondary structure of internal transcribed spacer (ITS) for family Gentianaceae in ITS data alignment. It examined 42 gentian species from Gentianaceae's six tribes including Chironieae, Helieae and Gentianeae and were submitted for DNA extraction. Results based on parsimony analysis and Bayesian methods showed that ITS alignment using secondary structure of Gentianaceae family helps in phylogenetic estimation among gentian species.