Molecular Phylogenetics and Taxonomy of the Genus &lt;I&gt;Boechera&lt;/I&gt; and Related Genera (Brassicaceae: Boechereae)

Alexander, Patrick J.; Windham, Michael D.; Beck, James B.; Al‐Shehbaz, Ihsan A.; Allphin, Loreen; Bailey, C. Donovan

doi:10.1600/036364413x661917

Cited by 40 publications

(127 citation statements)

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“…A number of studies have shown that polyploidy is very common in Boechera (Windham and Al-Shehbaz 2007;Alexander et al 2013). However polyploidy alone does not appear to explain all of the data presented here, because B. depauperata is also more tol-erant than the other polyploid Boechera in our study, B. californica.…”

Section: Relationship Of Thermotolerance Patterns To Species Habitatcontrasting

confidence: 65%

“…Seeds were sterilized, germinated, and grown using standardized protocols used for Arabidopsis (see ABRC: https://abrc.osu.edu/seed-handling). The systematics and taxonomy of the Boechera is in almost constant flux Al-Shehbaz 2006, 2007;Alexander et al 2013). We are using recent identifications of our collections and are also providing voucher information so that any subsequent name changes can be updated on these specimens.…”

Section: Growth Of Plants and Heat Stress Experimental Designmentioning

confidence: 99%

“…Boechera is a large genus of over 100 species that is restricted to North America, and is found mostly west of the Rockies Al-Shehbaz 2006, 2007). It represents a recent radiation and has been the focus of a number of recent systematic and ecological studies (Knight et al 2006;Alexander et al 2013;Naithani et al 2014;Gallas and Waters 2015). Here, we chose to examine four Boechera species that are native to California Al-Shehbaz 2006, 2007) The goals of this study are to examine the HS response and thermotolerance of four Boechera species, and to compare these results with the HS response and thermotolerance of A. thaliana.…”

Section: Introductionmentioning

confidence: 99%

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Patterns of thermotolerance, chlorophyll fluorescence, and heat shock gene expression vary among fourBoecheraspecies andArabidopsis thaliana

Halter

Simonetti

Suguitan

et al. 2017

Botany

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Thermotolerance is a property of all organisms, but owing to their sessile nature, this trait is particularly important in plants. Basal thermotolerance is based on inherent tolerance to heat stress. Acquired thermotolerance is attained through stress-induced gene expression, often of those genes encoding heat shock proteins (HSPs). Both basal and acquired thermotolerance have been extensively studied in model species such as Arabidopsis thaliana (L.) Heynh., but much less is known about thermotolerance in wild plant species. The aims of this study were to examine the basal and acquired thermotolerance of four species of Boechera, and of A. thaliana. Mots-clés : Arabidopsis, Boechera, fluorescence de la chlorophylle, expression génique induite par la chaleur, stress thermique, thermotolérance.

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Section: Relationship Of Thermotolerance Patterns To Species Habitatcontrasting

confidence: 65%

Section: Growth Of Plants and Heat Stress Experimental Designmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Patterns of thermotolerance, chlorophyll fluorescence, and heat shock gene expression vary among fourBoecheraspecies andArabidopsis thaliana

Halter

Simonetti

Suguitan

et al. 2017

Botany

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“…It is important to note that taxonomic revision within the Boechera genus is one of the daunting exercises for systematic botanists, as several Boechera species are known to repeatedly inter-hybridize, leading to novel species that are either sexuals or mostly facultative apomicts (Rushworth et al, 2011; Alexander et al, 2013). Several apomictic Boechera (diploid or polyploid) had been classified under B. holboellii clade and/or several others previously belong to this clade, e.g., B. divaricarpa (used in this study) had been reclassified into “trashcan” hybrids involving sexuals like B. stricta and B. sparsifolia (Rushworth et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Depletion of Key Meiotic Genes and Transcriptome-Wide Abiotic Stress Reprogramming Mark Early Preparatory Events Ahead of Apomeiotic Transition

et al. 2016

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Molecular dissection of apomixis – an asexual reproductive mode – is anticipated to solve the enigma of loss of meiotic sex, and to help fixing elite agronomic traits. The Brassicaceae genus Boechera comprises of both sexual and apomictic species, permitting comparative analyses of meiotic circumvention (apomeiosis) and parthenogenesis. Whereas previous studies reported local transcriptome changes during these events, it remained unclear whether global changes associated with hybridization, polyploidy and environmental adaptation that arose during evolution of Boechera might serve as (epi)genetic regulators of early development prior apomictic initiation. To identify these signatures during vegetative stages, we compared seedling RNA-seq transcriptomes of an obligate triploid apomict and a diploid sexual, both isolated from a drought-prone habitat. Uncovered were several genes differentially expressed between sexual and apomictic seedlings, including homologs of meiotic genes ASYNAPTIC 1 (ASY1) and MULTIPOLAR SPINDLE 1 (MPS1) that were down-regulated in apomicts. An intriguing class of apomict-specific deregulated genes included several NAC transcription factors, homologs of which are known to be transcriptionally reprogrammed during abiotic stress in other plants. Deregulation of both meiotic and stress-response genes during seedling stages might possibly be important in preparation for meiotic circumvention, as similar transcriptional alteration was discernible in apomeiotic floral buds too. Furthermore, we noted that the apomict showed better tolerance to osmotic stress in vitro than the sexual, in conjunction with significant upregulation of a subset of NAC genes. In support of the current model that DNA methylation epigenetically regulates stress, ploidy, hybridization and apomixis, we noted that ASY1, MPS1 and NAC019 homologs were deregulated in Boechera seedlings upon DNA demethylation, and ASY1 in particular seems to be repressed by global DNA methylation exclusively in the apomicts. Variability in stress and transcriptional response in a diploid apomict, which is geographically distinct from the triploid apomict, pinpoints both common and independent features of apomixis evolution. Our study provides a molecular frame-work to investigate how the adaptive traits associated with the evolutionary history of apomicts co-adapted with meiotic gene deregulation at early developmental stage, in order to predate meiotic recombination, which otherwise is thought to be favorable in stress and low-fitness conditions.

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“…The emerging model genus, Boechera (Brassicaceae) is such a system (Rushworth et al 2011). Boechera is characterized by diploid sexuals, and diploid and triploid apomicts which are distributed throughout North America (Al-Shehbaz 2003; Böcher 1951; Alexander et al 2013). …”

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confidence: 99%

On the origin and evolution of apomixis in Boechera

et al. 2013

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The genetic mechanisms causing seed development by gametophytic apomixis in plants are predominantly unknown. As apomixis is consistently associated with hybridity and polyploidy, these confounding factors may either A) be the underlying mechanism for the expression of apomixis, or B) obscure the genetic factors which cause apomixis. To distinguish between these hypotheses, we analyzed the population genetic patterns of diploid and triploid apomictic lineages and their sexual progenitors in the genus Boechera (Brassicaceae). We find that while triploid apomixis is associated with hybridization, the majority of diploid apomictic lineages are likely the product of intra-specific crosses. We then show that these diploid apomicts are more likely to sire triploid apomictic lineages than conspecific sexuals. Combined with flow cytometric seed screen phenotyping for male and female components of apomixis, our analyses demonstrate that hybridization is an indirect correlate of apomixis in Boechera. KeywordsBoechera; Apomixis; Apomeiosis; Hybridization; Polyploidy Sexual, outcrossing reproduction is the ancestral state of embryo development in flowering plants (Karron et al. 2012). This breeding system has generated much of the biodiversity on earth and provides species with the potential to adapt to changing conditions, thus improving the chance for long term survival. Despite these advantages, many groups of plants have independently evolved asexual methods to produce seed (van Dijk and Vijverberg 2005;Carman 1997). Among these mechanisms, gametophytic apomixis (hereon "apomixis") is one of the most common (Hörandl and Hojsgaard 2012 requires the coordination of several independent phenotypes including the formation of an unreduced embryo sac (female apomeiosis) and embryo development from an unfertilized and unreduced egg cell (parthenogenesis). Other traits, including the production of unreduced pollen (male apomeiosis) and the development of functional endosperm (e.g. pseudogamy) are typical of apomictic genotypes (Mogie 1992;Bicknell and Koltunow 2004). Considering that apomixis evolves from sexuality, the expression of any one of these traits alone would be deleterious. For example, female apomeiosis without parthenogenesis would lead to ploidy increases after each generation (although see Van Dijk & Vijverberg, 2005). The evolutionary mechanism causing the simultaneous establishment of these traits is the foremost debate in the apomixis literature.Many authors have suggested that the genome-wide affects of hybridization and polyploidy may induce apomixis (Carman 1997;Comai et al. 2003;Madlung et al. 2002;Sharbel et al. 2010; Wang et al. 2004) as evidenced by the nearly uniform pattern of hybridity and polyploidy in apomictic lineages (Pongratz et al. 1997;Bicknell and Koltunow 2004;Mogie 1986; Asker and Jerling 1992;Nelson-Jones et al. 2002). However, this correlation may be indirect: since apomictic lineages are expected to accumulate mutations through time (Hopf et al. 1988;Kondrashov 1985), hybridity ...

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Molecular Phylogenetics and Taxonomy of the Genus <I>Boechera</I> and Related Genera (Brassicaceae: Boechereae)

Cited by 40 publications

References 73 publications

Patterns of thermotolerance, chlorophyll fluorescence, and heat shock gene expression vary among fourBoecheraspecies andArabidopsis thaliana

Patterns of thermotolerance, chlorophyll fluorescence, and heat shock gene expression vary among fourBoecheraspecies andArabidopsis thaliana

Depletion of Key Meiotic Genes and Transcriptome-Wide Abiotic Stress Reprogramming Mark Early Preparatory Events Ahead of Apomeiotic Transition

On the origin and evolution of apomixis in Boechera

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