A Conserved Microbial Motif ‘Traps’ Protease Activation in Host Immunity

A recent study (Misas-Villamil et al., Nat. Commun., 2019) reveals that Pit2, an apoplastic effector of the corn smut fungus Ustilago maydis, contains an embedded motif of 14 amino acids that binds to and inhibits plant cysteine proteases, thereby modulating host immunity. Intriguingly, the inhibitory motif acts by mimicking the protease substrate and is conserved across microbial kingdoms

Marchantia polymorpha model reveals conserved infection mechanisms in the vascular wilt fungal pathogen Fusarium oxysporum

How co-evolution has shaped the interaction between plants andtheir associated microbes remains a central question in organis-mic interactions (Bonfante & Genre, 2010; Delaux & Schor-nack, 2021). Plants have evolved a sophisticated and multilayeredimmune system to ward off potential microbial invaders (Jones& Dangl, 2006; Boller & Felix, 2009). In addition, pathogenshave developed mechanisms allowing them to enter living plants,colonise their tissues and overcome their defence responses.Pathogenicity factors can be either broadly conserved or speciesspecific and include regulators of cell signalling, gene expressionor development, as well as secreted effector molecules that modu-late the host environment (Jongeet al., 2011; Turr aet al., 2014;Weiberget al., 2014; Prestiet al., 2015; Ryder & Talbot, 2015;van der Does & Rep, 2017).A particularly destructive group of plant pathogens are thosecausing vascular wilt diseases, which infect the roots and colonisethe highly protected and nutrient poor niche of the xylem(Yadeta & Thomma, 2013). The ascomycete fungusFusariumoxysporum(Fo) represents a species complex with worldwidedistribution that provokes devastating losses in more than 150different crops (Deanet al., 2012). Fo exhibits a hemibiotrophlifestyle with an initial biotrophic phase characterised by intercel-lular growth in the root cortex, followed by invasion of the vascu-lature and transition to the necrotrophic phase resulting inmaceration and death of the colonised host (Redkaret al., 2021).In the soil, Fo is able to locate roots by sensing secreted plant per-oxidases via its sex pheromone receptors and the cell wallintegrity mitogen activated protein kinase (MAPK) pathway(Turr aet al., 2015). Once inside the root, the fungus secretes asmall regulatory peptide that mimics plant Rapid ALkalinisationFactor (RALF) to induce host alkalisation, which in turn activatesa conserved MAPK cascade that promotes plant invasive growth(Masachiset al., 2016). Additional pathogenicity determinantsinclude transcriptional regulators, fungus/plant cell wall remod-elling components or secondary metabolites, among others(Michielse & Rep, 2009).Individual Fo isolates exhibit host-specific pathogenicity,which is determined by lineage-specific (LS) chromosomes thatencode distinct repertoires of effectors known as Secreted inXylem (Six) (Maet al., 2010; van Damet al., 2016). Some Six proteins appear to primarily target plant defence responses, butcan also be recognised as avirulence factors by specific host recep-tors (Houtermanet al., 2009; Tintoret al., 2020). In addition tothe pathogenic forms, the Fo species complex (FOSC) alsoincludes endophytic isolates such as Fo47, which was isolatedfrom a natural disease suppressive soil (Alabouvette, 1986; Wanget al., 2020). Fo47 colonises plant roots without causing wiltsymptoms and functions as a biological control agent againstpathogenic Fo strains. How vascular wilt fungi such as Fo gainedthe ability to associate with plant hosts and evolved endophyticand pathogenic lifestyles remains poorly understood.The bryophyteMarchantia polymorpha(Mp) belongs to theancient lineage of liverworts and has emerged as the primenonvascular plant model for studying the evolution of molecularplant–microbe interactions (Evo-MPMI), due to its low geneticredundancy, the simplicity of its gene families and an accessiblemolecular genetic toolbox (Ishizakiet al., 2008; Lockhart, 2015;Bowmanet al., 2017; Upsonet al., 2018; Gimenez-Ibanezet al.,2019). Importantly, Mp possesses receptor-like kinases (RLKs),nucleotide binding, leucine-rich repeat receptors (NLRs) and sal-icylic acid (SA) pathway genes similar to those mediatingimmune signalling in angiosperms (Xueet al., 2012; Bowmanet al., 2017), therefore allowing the study of plant–microbe inter-actions across evolutionarily distant land plant lineages such asliverworts and eudicots, which diverged>450 million years ago(Ma) (Carellaet al., 2018). A current shortcoming of Mp is thatonly few pathogen infection models have been developed forin vitropathogenicity assays. These include the fungiXylariacubensisandColletotrichum sp1, the oomycetePhytophthorapalmivoraand the Gram-negative bacteriumPseudomonassyringae(Nelsonet al., 2018; Carellaet al., 2019; Gimenez-Ibanezet al., 2019). A survey of the Mp microbiome identified anumber of fungal endophytes, some of which can also act aspathogens (Matsuiet al., 2019; Nelson & Shaw, 2019). Whetherroot-infecting vascular wilt fungi can colonise this land plant lin-eage, which is evolutionarily distant to eudicots and lacks bothtrue roots and xylem, is currently unknown.Here we established a new pathosystem between Fo and Mp.We find that Fo isolates that are either endophytic or pathogenicon different crops (tomato, banana, cotton) are all able tocolonise and macerate the thallus of this nonvascular plant. Infec-tion of Mp by Fo requires fungal core pathogenicity factors,whereas LS effectors are dispensable suggesting that this vascularwilt fungus employs conserved mechanisms during infection ofevolutionarily distant plant lineages. We further show that thefungal transition from biotrophic intercellular growth tonecrotrophic maceration and sporulation, which on angiospermsrelies on host-specific factors promoting xylem invasion, occursdirectly on the nonvascular plant Mp

Measurement of νˉμ\bar{\nu}_{\mu} and νμ\nu_{\mu} charged current inclusive cross sections and their ratio with the T2K off-axis near detector

We report a measurement of cross section $\sigma(\nu_{\mu}+{\rm nucleus}\rightarrow\mu^{-}+X)$ and the first measurements of the cross section $\sigma(\bar{\nu}_{\mu}+{\rm nucleus}\rightarrow\mu^{+}+X)$ and their ratio $R(\frac{\sigma(\bar \nu)}{\sigma(\nu)})$ at (anti-)neutrino energies below 1.5 GeV. We determine the single momentum bin cross section measurements, averaged over the T2K $\bar{\nu}/\nu$-flux, for the detector target material (mainly Carbon, Oxygen, Hydrogen and Copper) with phase space restricted laboratory frame kinematics of $\theta_{\mu}$500 MeV/c. The results are $\sigma(\bar{\nu})=\left( 0.900\pm0.029{\rm (stat.)}\pm0.088{\rm (syst.)}\right)\times10^{-39}$ and $\sigma(\nu)=\left( 2.41\ \pm0.022{\rm{(stat.)}}\pm0.231{\rm (syst.)}\ \right)\times10^{-39}$in units of cm$^{2}$/nucleon and$R\left(\frac{\sigma(\bar{\nu})}{\sigma(\nu)}\right)= 0.373\pm0.012{\rm (stat.)}\pm0.015{\rm (syst.)}$.Comment: 18 pages, 8 figure

Search for Lorentz and CPT violation using sidereal time dependence of neutrino flavor transitions over a short baseline

A class of extensions of the Standard Model allows Lorentz and CPT violations, which can be identified by the observation of sidereal modulations in the neutrino interaction rate. A search for such modulations was performed using the T2K on-axis near detector. Two complementary methods were used in this study, both of which resulted in no evidence of a signal. Limits on associated Lorentz and CPT-violating terms from the Standard Model extension have been derived by taking into account their correlations in this model for the first time. These results imply such symmetry violations are suppressed by a factor of more than 10 20 at the GeV scale

Measurement of ¯νμ and νμ charged current inclusive cross sections and their ratio with the T2K off-axis near detector

We report a measurement of cross section σ(νμ+nucleus→μ−+X) and the first measurements of the cross section σ(¯νμ+nucleus→μ++X) and their ratio R(σ(¯ν)σ(ν)) at (anti) neutrino energies below 1.5 GeV. We determine the single momentum bin cross section measurements, averaged over the T2K ¯ν/ν-flux, for the detector target material (mainly carbon, oxygen, hydrogen and copper) with phase space restricted laboratory frame kinematics of θμ500  MeV/c. The results are σ(¯ν)=(0.900±0.029(stat)±0.088(syst))×10−39 and σ(ν)=(2.41±0.022(stat)±0.231(syst))×10−39 in units of cm2/nucleon and R(σ(¯ν)σ(ν))=0.373±0.012(stat)±0.015(syst)

Updated T2K measurements of muon neutrino and antineutrino disappearance using 1.5 x 10(21) protons on target

We report measurements by the T2K experiment of the parameters $\theta_{23}$ and $\Delta m^{2}_{32}$ governing the disappearance of muon neutrinos and antineutrinos in the three flavor neutrino oscillation model. Utilizing the ability of the experiment to run with either a mainly neutrino or a mainly antineutrino beam, the parameters are measured separately for neutrinos and antineutrinos. Using $7.482 \times 10^{20}$ POT in neutrino running mode and $7.471 \times 10^{20}$ POT in antineutrino mode, T2K obtained, $\sin^{2}(\theta_{23})=0.51^{+0.08}_{-0.07}$ and $\Delta m^{2}_{32} = 2.53^{+0.15}_{-0.13} \times 10^{-3}$eV$^{2}$/c$^{4}$ for neutrinos, and $\sin^{2}({\overline{\theta}}_{23})=0.42^{+0.25}_{-0.07}$ and ${\Delta\overline{m}^2}_{32} = 2.55^{+0.33}_{-0.27} \times 10^{-3}$eV$^{2}$/c$^{4}$ for antineutrinos (assuming normal mass ordering). No significant differences between the values of the parameters describing the disappearance of muon neutrinos and antineutrinos were observed.Comment: 8 pages, 2 figure

Measurement of the single pi(0) production rate in neutral current neutrino interactions on water

The single π0 production rate in neutral current neutrino interactions on water in a neutrino beam with a peak neutrino energy of 0.6 GeV has been measured using the PØD, one of the subdetectors of the T2K near detector. The production rate was measured for data taking periods when the PØD contained water (2.64×10(20) protons-on-target) and also periods without water (3.49×10(20) protons-on-target). A measurement of the neutral current single π0 production rate on water is made using appropriate subtraction of the production rate with water in from the rate with water out of the target region. The subtraction analysis yields 106 ± 41 ± 69 signal events where the uncertainties are statistical (stat.) and systematic (sys.) respectively. This is consistent with the prediction of 157 events from the nominal simulation. The measured to expected ratio is 0.68 ± 0.26 (stat) ± 0.44 (sys) ± 0.12 (flux). The nominal simulation uses a flux integrated cross section of 7.63×10(−39)cm(2) per nucleon with an average neutrino interaction energy of 1.3 GeV

First measurement of the νμ charged-current cross section on a water target without pions in the final state

This paper reports the first differential measurement of the charged-current interaction cross section of νμ on water with no pions in the final state. This flux-averaged measurement has been made using the T2K experiment’s off-axis near detector, and is reported in doubly differential bins of muon momentum and angle. The flux-averaged total cross section in a restricted region of phase space was found to be σ=(0.95±0.08(stat)±0.06(det syst)±0.04(model syst)±0.08(flux))×10−38  cm2/n

Angular analysis of D0→π+π−μ+μ−D^0 \to \pi^+\pi^-\mu^+\mu^- and D0→K+K−μ+μ−D^0 \to K^+K^-\mu^+\mu^- decays and search for CPCP violation

The first full angular analysis and an updated measurement of the decay-rate $CP$ asymmetry of the $D^0 \to \pi^+\pi^-\mu^+\mu^-$ and $D^0 \to K^+K^-\mu^+\mu^-$ decays are reported. The analysis uses proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7, 8 and 13 TeV. The data set corresponds to an integrated luminosity of 9 fb$^{-1}$. The full set of $CP$-averaged angular observables and their $CP$ asymmetries are measured as a function of the dimuon invariant mass. The results are consistent with expectations from the standard model and with $CP$ symmetry.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2021-035.html (LHCb public pages

Observation of the doubly charmed baryon decay Ξcc++→Ξc′+π+

The Ξcc++→Ξc′+π+ decay is observed using proton-proton collisions collected by the LHCb experiment at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4 fb−1. The Ξcc++→Ξc′+π+ decay is reconstructed partially, where the photon from the Ξc′+→Ξc+γ decay is not reconstructed and the pK−π+ final state of the Ξc+ baryon is employed. The Ξcc++→Ξc′+π+branching fraction relative to that of the Ξcc++→Ξc+π+ decay is measured to be 1.41 ± 0.17 ± 0.10, where the first uncertainty is statistical and the second systematic. [Figure not available: see fulltext.