Analyses of Arabidopsis thaliana defense response to the damping-off oomycete pathogen Pythium irregulare show that resistance to P. irregulare requires a multicomponent defense strategy. Penetration ...represents a first layer, as indicated by the susceptibility of pen2 mutants, followed by recognition, likely mediated by ERECTA receptor-like kinases. Subsequent signaling of inducible defenses is predominantly mediated by jasmonic acid (JA), with insensitive coi1 mutants showing extreme susceptibility. In contrast with the generally accepted roles of ethylene and salicylic acid cooperating with or antagonizing, respectively, JA in the activation of defenses against necrotrophs, both are required to prevent disease progression, although much less so than JA. Meta-analysis of transcriptome profiles confirmed the predominant role of JA in activation of P. irregulare-induced defenses and uncovered abscisic acid (ABA) as an important regulator of defense gene expression. Analysis of cis-regulatory sequences also revealed an unexpected overrepresentation of ABA response elements in promoters of P. irregulare-responsive genes. Subsequent infections of ABA-related and callose-deficient mutants confirmed the importance of ABA in defense, acting partly through an undescribed mechanism. The results support a model for ABA affecting JA biosynthesis in the activation of defenses against this oomycete.
A
bstract
We construct families of supersymmetric AdS
3
×
Y
7
and AdS
3
×
Y
8
solutions to type IIB string theory and M-theory, respectively. Here
Y
7
is an
S
5
fibration over Σ, while
Y
8
is an
S
4
...fibration over Σ
g
× Σ, where Σ
g
is a Riemann surface of genus
g >
1 and Σ is a two-dimensional orbifold known as a spindle. We interpret the solutions as near-horizon limits of
N
D3-branes wrapped on Σ and
N
M5-branes wrapped on Σ
g
× Σ, respectively. These are holographically dual to
d
= 2, (0
,
2) SCFTs, and we show that the central charge and superconformal R-symmetry of the gravity solutions agree with dual field theory calculations.
Accelerating black holes and spinning spindles Ferrero, Pietro; Gauntlett, Jerome P.; Pérez Ipiña, Juan Manuel ...
Physical review. D,
08/2021, Letnik:
104, Številka:
4
Journal Article
Recenzirano
Odprti dostop
We study solutions in the Plebański–Demiański family which describe an accelerating, rotating, and dyonically charged black hole in AdS 4 . These are solutions of D = 4 Einstein-Maxwell theory with a ...negative cosmological constant and hence minimal D = 4 gauged supergravity. It is well known that when the acceleration is nonvanishing the D = 4 black hole metrics have conical singularities. By uplifting the solutions to D = 11 supergravity using a regular Sasaki-Einstein seven-manifold, SE7, we show how the free parameters can be chosen to eliminate the conical singularities. Topologically, the D = 11 solutions incorporate an S E 7 fibration over a two-dimensional weighted projective space, WCP1n−, n+, also known as a spindle, which is labeled by two integers that determine the conical singularities of the D = 4 metrics. We also discuss the supersymmetric and extremal limit and show that the near horizon limit gives rise to a new family of regular supersymmetric AdS2 × Y9 solutions of D = 11 supergravity, which generalize a known family by the addition of a rotation parameter. We calculate the entropy of these black holes and argue that it should be possible to derive this from certain N = 2 , d = 3 quiver gauge theories compactified on a spinning spindle with the appropriate magnetic flux.
Adventitious roots (ARs) are produced from non‐root tissues in response to different environmental signals, such as abiotic stresses, or after wounding, in a complex developmental process that ...requires hormonal crosstalk. Here, we characterized AR formation in young seedlings of Solanum lycopersicum cv. ‘Micro‐Tom’ after whole root excision by means of physiological, genetic and molecular approaches. We found that a regulated basipetal auxin transport from the shoot and local auxin biosynthesis triggered by wounding are both required for the re‐establishment of internal auxin gradients within the vasculature. This promotes cell proliferation at the distal cambium near the wound in well‐defined positions of the basal hypocotyl and during a narrow developmental window. In addition, a pre‐established pattern of differential auxin responses along the apical‐basal axis of the hypocotyl and an as of yet unknown cell‐autonomous inhibitory pathway contribute to the temporal and spatial patterning of the newly formed ARs on isolated hypocotyl explants. Our work provides an experimental outline for the dissection of wound‐induced AR formation in tomato, a species that is suitable for molecular identification of gene regulatory networks via forward and reverse genetics approaches.
We found that wound‐induced adventitious root formation in tomato (Solanum lycopersicum cv. ‘Micro‐Tom’) shoot explants requires both long‐range and short‐range regulation of auxin levels through polar auxin transport and local auxin biosynthesis.
To determine whether root‐supplied ABA alleviates saline stress, tomato (Solanum lycopersicum L. cv. Sugar Drop) was grafted onto two independent lines (NCED OE) overexpressing the SlNCED1 gene ...(9‐cis‐epoxycarotenoid dioxygenase) and wild type rootstocks. After 200 days of saline irrigation (EC = 3.5 dS m−1), plants with NCED OE rootstocks had 30% higher fruit yield, but decreased root biomass and lateral root development. Although NCED OE rootstocks upregulated ABA‐signalling (AREB, ATHB12), ethylene‐related (ACCs, ERFs), aquaporin (PIPs) and stress‐related (TAS14, KIN, LEA) genes, downregulation of PYL ABA receptors and signalling components (WRKYs), ethylene synthesis (ACOs) and auxin‐responsive factors occurred. Elevated SlNCED1 expression enhanced ABA levels in reproductive tissue while ABA catabolites accumulated in leaf and xylem sap suggesting homeostatic mechanisms. NCED OE also reduced xylem cytokinin transport to the shoot and stimulated foliar 2‐isopentenyl adenine (iP) accumulation and phloem transport. Moreover, increased xylem GA3 levels in growing fruit trusses were associated with enhanced reproductive growth. Improved photosynthesis without changes in stomatal conductance was consistent with reduced stress sensitivity and hormone‐mediated alteration of leaf growth and mesophyll structure. Combined with increases in leaf nutrients and flavonoids, systemic changes in hormone balance could explain enhanced vigour, reproductive growth and yield under saline stress.
ABA overproducing tomato rootstocks increase shoot vigour and fruit yield under saline conditions by altering stress‐related responses, improving photosynthesis and optimizing source‐sink relationships.
In Arabidopsis thaliana, mutations in genes encoding ribosomal proteins (r-proteins) perturb various developmental processes. Whether these perturbations are caused by overall ribosome insufficiency ...or partial dysfunction of the ribosome caused by deficiency of a particular ribosomal protein is not known. To distinguish these possibilities, a comparative study using several r-protein mutants was required. Here, we identified mutations in 11 r-protein genes from previously isolated denticulata and pointed-leaves mutants. Most of these mutations were associated with pointed leaves, with reduced growth due to a decrease in the number or size of palisade mesophyll and pavement cells. In addition, leaf abaxialization was usually observed when these r-protein mutations were combined with asymmetric leaves1 (as1) and as2 mutations. These results suggest that the establishment of leaf polarity is highly sensitive to ribosome functionality in general. However, several r-protein mutants showed a preference towards a specific developmental defect. For example, rpl4d mutations did not affect cell proliferation but caused strong abaxialization of leaves in the as1 and as2 backgrounds. On the other hand, rps28b enhanced leaf abaxialization of as2 to a weaker extent than expected on the basis of its negative effect on cell proliferation. In addition, hypomorphic rps6a alleles had the strongest effects on most of the phenotypes examined. These findings suggest that deficiencies in these three r-protein genes lead to production of dysfunctional ribosomes. Depending on their structural abnormalities, dysfunctional ribosomes may affect translation of specific transcripts involved in the regulation of some leaf developmental processes.
Adventitious root (AR) formation in excised plant parts is a bottleneck for survival of isolated plant fragments. AR formation plays an important ecological role and is a critical process in cuttings ...for the clonal propagation of horticultural and forestry crops. Therefore, understanding the regulation of excision-induced AR formation is essential for sustainable and efficient utilization of plant genetic resources.
Recent studies of plant transcriptomes, proteomes and metabolomes, and the use of mutants and transgenic lines have significantly expanded our knowledge concerning excision-induced AR formation. Here, we integrate new findings regarding AR formation in the cuttings of diverse plant species. These findings support a new system-oriented concept that the phytohormone-controlled reprogramming and differentiation of particular responsive cells in the cutting base interacts with a co-ordinated reallocation of plant resources within the whole cutting to initiate and drive excision-induced AR formation. Master control by auxin involves diverse transcription factors and mechanically sensitive microtubules, and is further linked to ethylene, jasmonates, cytokinins and strigolactones. Hormone functions seem to involve epigenetic factors and cross-talk with metabolic signals, reflecting the nutrient status of the cutting. By affecting distinct physiological units in the cutting, environmental factors such as light, nitrogen and iron modify the implementation of the genetically controlled root developmental programme.
Despite advanced research in the last decade, important questions remain open for future investigations on excision-induced AR formation. These concern the distinct roles and interactions of certain molecular, hormonal and metabolic factors, as well as the functional equilibrium of the whole cutting in a complex environment. Starting from model plants, cell type- and phase-specific monitoring of controlling processes and modification of gene expression are promising methodologies that, however, need to be integrated into a coherent model of the whole system, before research findings can be translated to other crops.
FAIR (findability, accessibility, interoperability, and reusability) guiding principles seek the reuse of data and other digital research input, output, and objects (algorithms, tools, and workflows ...that led to that data) making them findable, accessible, interoperable, and reusable. GO FAIR - a bottom-up, stakeholder driven and self-governed initiative - defined a seven-step FAIRification process focusing on data, but also indicating the required work for metadata. This FAIRification process aims at addressing the translation of raw datasets into FAIR datasets in a general way, without considering specific requirements and challenges that may arise when dealing with some particular types of data.
This scientific contribution addresses the architecture design of an open technological solution built upon the FAIRification process proposed by "GO FAIR" which addresses the identified gaps that such process has when dealing with health datasets.
A common FAIRification workflow was developed by applying restrictions on existing steps and introducing new steps for specific requirements of health data. These requirements have been elicited after analyzing the FAIRification workflow from different perspectives: technical barriers, ethical implications, and legal framework. This analysis identified gaps when applying the FAIRification process proposed by GO FAIR to health research data management in terms of data curation, validation, deidentification, versioning, and indexing.
A technological architecture based on the use of Health Level Seven International (HL7) FHIR (fast health care interoperability resources) resources is proposed to support the revised FAIRification workflow.
Research funding agencies all over the world increasingly demand the application of the FAIR guiding principles to health research output. Existing tools do not fully address the identified needs for health data management. Therefore, researchers may benefit in the coming years from a common framework that supports the proposed FAIRification workflow applied to health datasets.
Routine health care datasets or data resulting from health research can be FAIRified, shared and reused within the health research community following the proposed FAIRification workflow and implementing technical architecture.
Summary
The characterization of mutants with altered leaf shape and pigmentation has previously allowed the identification of nuclear genes that encode plastid‐localized proteins that perform ...essential functions in leaf growth and development. A large‐scale screen previously allowed us to isolate ethyl methanesulfonate‐induced mutants with small rosettes and pale green leaves with prominent marginal teeth, which were assigned to a phenotypic class that we dubbed Angulata. The molecular characterization of the 12 genes assigned to this phenotypic class should help us to advance our understanding of the still poorly understood relationship between chloroplast biogenesis and leaf morphogenesis. In this article, we report the phenotypic and molecular characterization of the angulata7‐1 (anu7‐1) mutant of Arabidopsis thaliana, which we found to be a hypomorphic allele of the EMB2737 gene, which was previously known only for its embryonic‐lethal mutations. ANU7 encodes a plant‐specific protein that contains a domain similar to the central cysteine‐rich domain of DnaJ proteins. The observed genetic interaction of anu7‐1 with a loss‐of‐function allele of GENOMES UNCOUPLED1 suggests that the anu7‐1 mutation triggers a retrograde signal that leads to changes in the expression of many genes that normally function in the chloroplasts. Many such genes are expressed at higher levels in anu7‐1 rosettes, with a significant overrepresentation of those required for the expression of plastid genome genes. Like in other mutants with altered expression of plastid‐encoded genes, we found that anu7‐1 exhibits defects in the arrangement of thylakoidal membranes, which appear locally unappressed.
Significance Statement
The relationship between chloroplast biogenesis and leaf morphogenesis is still poorly understood. Characterizing mutants with altered leaf shape and pigmentation can allow the identification of nuclear genes that encode plastid‐localized proteins that perform essential functions in leaf growth and development. Here we show that angulata7‐1 (anu7‐1) is a hypomorphic allele of EMB2737, previously known only for its embryonic lethal alleles. We show that the ANU7/EMB2737 protein is required for the expression of the plastid genome and for the arrangement of thylakoidal membranes.
Organofluorophosphonium salts of the formula (C6F5)3–x Ph x PFB(C6F5)4 (x = 0, 1) exhibit Lewis acidity derived from a low-lying σ* orbital at P opposite F. This acidity is evidenced by the reactions ...of these salts with olefins, which catalyze the rapid isomerization of 1-hexene to 2-hexene, the cationic polymerization of isobutylene, and the Friedel–Crafts-type dimerization of 1,1-diphenylethylene. In the presence of hydrosilanes, olefins and alkynes undergo efficient hydrosilylation catalysis to the alkylsilanes. Experimental and computational considerations of the mechanism are consistent with the sequential activation and 1,2-addition of hydrosilane across the unsaturated C–C bonds.
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