8 research outputs found
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Low relative humidity triggers RNA-directed de novo DNA methylation and suppression of genes controlling stomatal development
Environmental cues influence the development of stomata on the leaf epidermis, and allow plants to exert plasticity
in leaf stomatal abundance in response to the prevailing growing conditions. It is reported that Arabidopsis thaliana
‘Landsberg erecta’ plants grown under low relative humidity have a reduced stomatal index and that two genes in
the stomatal development pathway, SPEECHLESS and FAMA, become de novo cytosine methylated and
transcriptionally repressed. These environmentally-induced epigenetic responses were abolished in mutants lacking
the capacity for de novo DNA methylation, for the maintenance of CG methylation, and in mutants for the production
of short-interfering non-coding RNAs (siRNAs) in the RNA-directed DNA methylation pathway. Induction of
methylation was quantitatively related to the induction of local siRNAs under low relative humidity. Our results
indicate the involvement of both transcriptional and post-transcriptional gene suppression at these loci in response
to environmental stress. Thus, in a physiologically important pathway, a targeted epigenetic response to a specific
environmental stress is reported and several of its molecular, mechanistic components are described, providing
a tractable platform for future epigenetics experiments. Our findings suggest epigenetic regulation of stomatal
development that allows for anatomical and phenotypic plasticity, and may help to explain at least some of the
plant’s resilience to fluctuating relative humidity
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Pre-conditioning the epigenetic response to high vapor pressure deficit increases the drought tolerance of Arabidopsis thaliana
Epigenetic modification of the genome via cytosine methylation is a dynamic process that responds to changes in the growing environment. This modification can also be heritable. The combination of both properties means that there is the potential for the life experiences of the parental generation to modify the methylation profiles of their offspring and so potentially to ‘pre-condition’ them to better accommodate abiotic conditions encountered by their parents. We recently identified high vapor pressure deficit (vpd)-induced DNA methylation at two gene loci in the stomatal development pathway and an associated reduction in leaf stomatal frequency.1 Here, we test whether this epigenetic modification pre-conditioned parents and their offspring to the more severe water stress of periodic drought. We found that three generations of high vpd-grown plants were better able to withstand periodic drought stress over two generations. This resistance was not directly associated with de novo methylation of the target stomata genes, but was associated with the cmt3 mutant’s inability to maintain asymmetric sequence context methylation. If our finding applies widely, it could have significant implications for evolutionary biology and breeding for stressful environments
A randomised, controlled, two-Centre open-label study in healthy Japanese subjects to evaluate the effect on biomarkers of exposure of switching from a conventional cigarette to a tobacco heating product
Good Dog SPOT? Single Pot Funding of Local Voluntary and Community Groups
This paper reports on a recent pilot project by the English government aimed at introducing 'single pot' funding for local voluntary and community groups. It finds that implementation difficulties undermined the success of the scheme. Moreover, whilst local voluntary and community groups were initially enthusiastic about the scheme, this was eroded both by the shortfall in funding for the initiative and by conflicting priorities for it from its national and regional flinders and from local groups.