A cluster of MYB transcription factors regulates anthocyanin biosynthesis in carrot (Daucus carota L.) root and petiole

Purple carrots can accumulate large quantities of anthocyanins in their roots and – in some genetic backgrounds-petioles, and therefore they represent an excellent dietary source of antioxidant phytonutrients. In a previous study, using linkage analysis in a carrot F 2 mapping population segregating for root and petiole anthocyanin pigmentation, we identified a region in chromosome 3 with co-localized QTL for all anthocyanin pigments of the carrot root, whereas petiole pigmentation segregated as a single dominant gene and mapped to one of these “root pigmentation” regions conditioning anthocyanin biosynthesis. In the present study, we performed fine mapping combined with gene expression analyses (RNA-Seq and RT-qPCR) to identify candidate genes controlling anthocyanin pigmentation in the carrot root and petiole. Fine mapping was performed in four carrot populations with different genetic backgrounds and patterns of pigmentation. The regions controlling root and petiole pigmentation in chromosome 3 were delimited to 541 and 535 kb, respectively. Genome wide prediction of transcription factor families known to regulate the anthocyanin biosynthetic pathway coupled with orthologous and phylogenetic analyses enabled the identification of a cluster of six MYB transcription factors, denominated DcMYB6 to DcMYB11, associated with the regulation of anthocyanin biosynthesis. No anthocyanin biosynthetic genes were present in this region. Comparative transcriptome analysis indicated that upregulation of DcMYB7 was always associated with anthocyanin pigmentation in both root and petiole tissues, whereas DcMYB11 was only upregulated with pigmentation in petioles. In the petiole, the level of expression of DcMYB11 was higher than DcMYB7. DcMYB6, a gene previously suggested as a key regulator of carrot anthocyanin biosynthesis, was not consistently associated with pigmentation in either tissue. These results strongly suggest that DcMYB7 is a candidate gene for root anthocyanin pigmentation in all the genetic backgrounds included in this study. DcMYB11 is a candidate gene for petiole pigmentation in all the purple carrot sources in this study. Since DcMYB7 is co-expressed with DcMYB11 in purple petioles, the latter gene may act also as a co-regulator of anthocyanin pigmentation in the petioles. This study provides linkage-mapping and functional evidence for the candidacy of these genes for the regulation of carrot anthocyanin biosynthesis.Fil: Iorizzo, Massimo. North Carolina State University. Department Of Food, Bioprocessing And Nutrition Sciences. Plants For Human Health Institute; Estados UnidosFil: Cavagnaro, Pablo Federico. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria La Consulta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción Agropecuaria. Cátedra de Horticultura y Floricultura; ArgentinaFil: Bolstan, Hamed. North Carolina State University. Department Of Food, Bioprocessing And Nutrition Sciences. Plants For Human Health Institute; Estados UnidosFil: Zhao, Yunyang. North Carolina State University. Department Of Food, Bioprocessing And Nutrition Sciences. Plants For Human Health Institute; Estados UnidosFil: Zhang, Jianhui. North Carolina State University. Department Of Food, Bioprocessing And Nutrition Sciences. Plants For Human Health Institute; Estados UnidosFil: Simon, Philipp W.. United States Department of Agriculture. Agricultural Research Service; Argentina. University of Wisconsin; Estados Unido

Identification of an SCPL gene controlling anthocyanin acylation in carrot (Daucus carota L.) root

Anthocyanins are natural health promoting pigments that can be produced in large quantities in some purple carrot cultivars. Decoration patterns of anthocyanins, such as acylation, can greatly influence their stability and biological properties and use in the food industry as nutraceuticals and natural colorants. Despite recent advances made toward understanding the genetic control of anthocyanin accumulation in purple carrot, the genetic mechanism controlling acylation of anthocyanin in carrot root have not been studied yet. In the present study, we performed fine mapping combined with gene expression analyses (RNA-Seq and RT-qPCR) to identify the genetic factor conditioning the accumulation of non-acylated (Cy3XGG) versus acylated (Cy3XFGG and Cy3XSGG) cyanidin derivatives, in three carrot populations. Segregation and mapping analysis pointed to a single gene with dominant effect controlling anthocyanin acylation in the root, located in a 576kb region containing 29 predicted genes. Orthologous and phylogenetic analyses enabled the identification of a cluster of three SCPL-acyltransferases coding genes within this region. Comparative transcriptome analysis indicated that only one of these three genes, DcSCPL1, was always expressed in association with anthocyanin pigmentation in the root and was co-expressed with DcMYB7, a gene known to activate anthocyanin biosynthetic genes in carrot. DcSCPL1 sequence analysis, in root tissue containing a low level of acylated anthocyanins, demonstrated the presence of an insertion causing an abnormal splicing of the 3rd exon during mRNA editing, likely resulting in the production of a non-functional acyltransferase and explaining the reduced acylation phenotype. This study provides strong linkage-mapping and functional evidences for the candidacy of DcSCPL1 as a primary regulator of anthocyanin acylation in carrot storage root.Fil: Curaba, Julien. North Carolina State University. Department Of Food, Bioprocessing And Nutrition Sciences. Plants For Human Health Institute.; Estados UnidosFil: Bostan, Hamed. North Carolina State University. Department Of Food, Bioprocessing And Nutrition Sciences. Plants For Human Health Institute.; Estados UnidosFil: Cavagnaro, Pablo Federico. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria La Consulta; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción Agropecuaria. Cátedra de Horticultura y Floricultura; ArgentinaFil: Senalik, Douglas A.. United States Department of Agriculture. Agricultural Research Service; ArgentinaFil: Mengist, Molla Fentie. North Carolina State University. Department Of Food, Bioprocessing And Nutrition Sciences. Plants For Human Health Institute.; Estados UnidosFil: Zhao, Yunyang. North Carolina State University. Department Of Food, Bioprocessing And Nutrition Sciences. Plants For Human Health Institute.; Estados UnidosFil: Simon, Philipp W.. United States Department of Agriculture. Agricultural Research Service; ArgentinaFil: Iorizzo, Massimo. North Carolina State University. Department Of Food, Bioprocessing And Nutrition Sciences. Plants For Human Health Institute.; Estados Unido

Impact Analysis of Energy Storage Participating in Peak Shaving and Valley Filling for Distribution Network on Network Loss and Voltage Deviation

[Introduction] The application scenarios of peak shaving and valley filling by energy storage connected to the distribution network are studied to clarify the influence of energy storage access on network losses and voltage quality on the distribution network side. [Method] The paper analyzed the change trend of network loss power with the energy storage injection current and access position during peak hours of energy storage discharge, and then analyzed the change trend of network loss power with the energy storage injection current and access position when the energy storage system was connected and charged during valley hours. For the influence of energy storage connected to the distribution network for peak shaving and valley filling on the voltage of the distribution network, the influence of different energy storage injection currents and access positions on the voltage distribution along the distribution network was studied from the perspective of energy storage discharge during peak hours and energy storage charging during valley hours. Finally, considering the total voltage deviation index of the distribution network, the influence on the total voltage deviation index after the distribution network which was connected to energy storage was studied. [Result] Through simulation calculations, the influence trend of energy storage participating in peak shaving and valley filling for the distribution network on network loss power and voltage loss is analyzed when different fixed or continuous values of energy storage current and access position are taken, and it is compared with theoretical analysis. [Conclusion] The study will provide useful references for the coordinated planning and optimized operation of various energy storage facilities in the distribution network, and it has good engineering reference value

Molecular characterization of a rice mutator-phenotype derived from an incompatible cross-pollination reveals transgenerational mobilization of multiple transposable elements and extensive epigenetic instability

BACKGROUND: Inter-specific hybridization occurs frequently in plants, which may induce genetic and epigenetic instabilities in the resultant hybrids, allopolyploids and introgressants. It remains unclear however whether pollination by alien pollens of an incompatible species may impose a "biological stress" even in the absence of genome-merger or genetic introgression, whereby genetic and/or epigenetic instability of the maternal recipient genome might be provoked. RESULTS: We report here the identification of a rice mutator-phenotype from a set of rice plants derived from a crossing experiment involving two remote and apparently incompatible species, Oryza sativa L. and Oenothera biennis L. The mutator-phenotype (named Tong211-LP) showed distinct alteration in several traits, with the most striking being substantially enlarged panicles. Expectably, gel-blotting by total genomic DNA of the pollen-donor showed no evidence for introgression. Characterization of Tong211-LP (S0) and its selfed progenies (S1) ruled out contamination (via seed or pollen) or polyploidy as a cause for its dramatic phenotypic changes, but revealed transgenerational mobilization of several previously characterized transposable elements (TEs), including a MITE (mPing), and three LTR retrotransposons (Osr7, Osr23 and Tos17). AFLP and MSAP fingerprinting revealed extensive, transgenerational alterations in cytosine methylation and to a less extent also genetic variation in Tong211-LP and its immediate progenies. mPing mobility was found to correlate with cytosine methylation alteration detected by MSAP but not with genetic variation detected by AFLP. Assay by q-RT-PCR of the steady-state transcript abundance of a set of genes encoding for the various putative DNA methyltransferases, 5-methylcytosine DNA glycosylases, and small interference RNA (siRNA) pathway-related proteins showed that, relative to the rice parental line, heritable perturbation in expression of 12 out of the 13 genes occurred in the mutator-phenotype and its sefled progenies. CONCLUSION: Transgenerational epigenetic instability in the form of altered cytosine methylation and its associated TE activity occurred in a rice mutator-phenotype produced by pollinating the rice stigma with pollens of O. biennis. Heritably perturbed homeostatic expression-state of genes involved in maintenance of chromatin structure is likely an underlying cause for the alien pollination-induced transgenerational epigenetic/genetic instability, and which occurred apparently without entailing genome merger or genetic introgression

A Cluster of MYB Transcription Factors Regulates Anthocyanin Biosynthesis in Carrot (Daucus carota L.) Root and Petiole

Purple carrots can accumulate large quantities of anthocyanins in their roots and –in some genetic backgrounds- petioles, and therefore they represent an excellent dietary source of antioxidant phytonutrients. In a previous study, using linkage analysis in a carrot F2 mapping population segregating for root and petiole anthocyanin pigmentation, we identified a region in chromosome 3 with co-localized QTL for all anthocyanin pigments of the carrot root, whereas petiole pigmentation segregated as a single dominant gene and mapped to one of these “root pigmentation” regions conditioning anthocyanin biosynthesis. In the present study, we performed fine mapping combined with gene expression analyses (RNA-Seq and RT-qPCR) to identify candidate genes controlling anthocyanin pigmentation in the carrot root and petiole. Fine mapping was performed in four carrot populations with different genetic backgrounds and patterns of pigmentation. The regions controlling root and petiole pigmentation in chromosome 3 were delimited to 541 and 535 kb, respectively. Genome wide prediction of transcription factor families known to regulate the anthocyanin biosynthetic pathway coupled with orthologous and phylogenetic analyses enabled the identification of a cluster of six MYB transcription factors, denominated DcMYB6 to DcMYB11, associated with the regulation of anthocyanin biosynthesis. No anthocyanin biosynthetic genes were present in this region. Comparative transcriptome analysis indicated that upregulation of DcMYB7 was always associated with anthocyanin pigmentation in both root and petiole tissues, whereas DcMYB11 was only upregulated with pigmentation in petioles. In the petiole, the level of expression of DcMYB11 was higher than DcMYB7. DcMYB6, a gene previously suggested as a key regulator of carrot anthocyanin biosynthesis, was not consistently associated with pigmentation in either tissue. These results strongly suggest that DcMYB7 is a candidate gene for root anthocyanin pigmentation in all the genetic backgrounds included in this study. DcMYB11 is a candidate gene for petiole pigmentation in all the purple carrot sources in this study. Since DcMYB7 is co-expressed with DcMYB11 in purple petioles, the latter gene may act also as a co-regulator of anthocyanin pigmentation in the petioles. This study provides linkage-mapping and functional evidence for the candidacy of these genes for the regulation of carrot anthocyanin biosynthesis

Solenoid-free current drive via ECRH in EXL-50 spherical torus plasmas

As a new spherical tokamak (ST) designed to simplify engineering requirements of a possible future fusion power source, the EXL-50 experiment features a low aspect ratio (A) vacuum vessel (VV), encircling a central post assembly containing the toroidal field coil conductors without a central solenoid. Multiple electron cyclotron resonance heating (ECRH) resonances are located within the VV to improve current drive effectiveness. Copious energetic electrons are produced and measured with hard X-ray detectors, carry the bulk of the plasma current ranging from 50kA to 150kA, which is maintained for more than 1s duration. It is observed that over one Ampere current can be maintained per Watt of ECRH power issued from the 28-GHz gyrotrons. The plasma current reaches Ip>80kA for high density (>5e18me-2) discharge with 150kW ECHR heating. An analysis was carried out combining reconstructed multi-fluid equilibrium, guiding-center orbits of energetic electrons, and resonant heating mechanisms. It is verified that in EXL-50 a broadly distributed current of energetic electrons creates smaller closed magnetic-flux surfaces of low aspect ratio that in turn confine the thermal plasma electrons and ions and participate in maintaining the equilibrium force-balance

Detecting Neutrinos from Supernova Bursts in PandaX-4T

Neutrinos from core-collapse supernovae are essential for the understanding of neutrino physics and stellar evolution. The dual-phase xenon dark matter detectors can provide a way to track explosions of galactic supernovae by detecting neutrinos through coherent elastic neutrino-nucleus scatterings. In this study, a variation of progenitor masses as well as explosion models are assumed to predict the neutrino fluxes and spectra, which result in the number of expected neutrino events ranging from 6.6 to 13.7 at a distance of 10 kpc over a 10-second duration with negligible backgrounds at PandaX-4T. Two specialized triggering alarms for monitoring supernova burst neutrinos are built. The efficiency of detecting supernova explosions at various distances in the Milky Way is estimated. These alarms will be implemented in the real-time supernova monitoring system at PandaX-4T in the near future, providing the astronomical communities with supernova early warnings.Comment: 9 pages,6 figure

Search for light dark matter from atmosphere in PandaX-4T

We report a search for light dark matter produced through the cascading decay of $\eta$ mesons, which are created as a result of inelastic collisions between cosmic rays and Earth's atmosphere. We introduce a new and general framework, publicly accessible, designed to address boosted dark matter specifically, with which a full and dedicated simulation including both elastic and quasi-elastic processes of Earth attenuation effect on the dark matter particles arriving at the detector is performed. In the PandaX-4T commissioning data of 0.63 tonne$\cdot$year exposure, no significant excess over background is observed. The first constraints on the interaction between light dark matter generated in the atmosphere and nucleus through a light scalar mediator are obtained. The lowest excluded cross-section is set at $5.9 \times 10^{-37}{\rm cm^2}$ for dark matter mass of $0.1$ MeV$/c^2$ and mediator mass of 300 MeV$/c^2$. The lowest upper limit of $\eta$ to dark matter decay branching ratio is $1.6 \times 10^{-7}$

A Search for Light Fermionic Dark Matter Absorption on Electrons in PandaX-4T

We report a search on a sub-MeV fermionic dark matter absorbed by electrons with an outgoing active neutrino using the 0.63 tonne-year exposure collected by PandaX-4T liquid xenon experiment. No significant signals are observed over the expected background. The data are interpreted into limits to the effective couplings between such dark matter and electrons. For axial-vector or vector interactions, our sensitivity is competitive in comparison to existing astrophysical bounds on the decay of such dark matter into photon final states. In particular, we present the first direct detection limits for an axial-vector (vector) interaction which are the strongest in the mass range from 25 to 45 (35 to 50) keV/c$^2$

UNDERSTANDING THE GENETICS OF PEDICEL-FRUIT RETENTION FORCE IN SWEET CHERRY (PRUNUS AVIUM L.)

Sweet cherry (Prunus avium L.) is a labor-intensive fruit crop due to hand harvesting. To enable adoption of mechanical harvest, it is necessary to develop new sweet cherry cultivars with low pedicel-fruit retention force (PFRF). This research aimed to identify the genetic mechanisms underlying PFRF and key fruit traits [soluble solids content (SSC) and titratable acidity (TA)] to facilitate developing new high quality stem-less cherries. Initial phenotyping of PFRF and fruit quality attributes showed minimal correlations, highlighting the possibility to combine both low PFRF and excellent fruit quality through strategic breeding. The effects of genotype, year and genotype × year interaction on PFRF were significant (p TM for PFRF, SSC and TA using 2010, 2011 and 2012 phenotypic data. Six QTL for PFRF were mapped on the `Texas'(almond) x `Earlygold' (peach) Prunus reference map on linkage group (LG) 1 (one in 2011), LG 2 (one in 2010, the other in 2011 and 2012), LG 4 (one in 2012), and LG 8 (two in 2011). Three QTL for SSC were detected; one on LG 2 in 2011 and 2012, one on LG 4 in 2012 and a minor one on LG 7 in 2011. Three QTL were identified for TA; one mapped on LG 2 in 2010, the other on LG 4 in 2011 and 2012 while the third was mapped on LG 6 in 2012 . The LG 2 QTL was closely linked or co-localized between PFRF and SSC in both 2011 and 2012 while the QTL on LG 4 was closely linked or co-localized among PFRF, SSC and TA in 2012. The implications of these results are discussed in relation to breeding for PFRF and fruit quality in sweet cherry