Use of PCR to detect infection of differentially susceptible maize cultivars using Ustilago maydis strains of variable virulence

Ustilago maydis was specifically detected in infected maize plants by means of the polymerase chain reaction (PCR) using oligonucleotides corresponding to a specific region downstream of the homeodomain of the bE genes of the pathogen. The reaction gave rise to amplification of a ca. 500-bp product when tested with U. maydis DNA, but no amplification was detected with DNA from fungi not related to U. maydis. Using these primers, U. maydis was detected in infected maize plants from differentially susceptible cultivars as early as 4 days after inoculation with strains of variable degrees of virulence. Detection of U. maydis at early stages of infection, or in asymptomatic infected plants should assist in studies on plant–pathogen interactions

Caracterización del microbioma de plantas de banano (Musa × paradisiaca L.) bajo sistemas de producción orgánico y convencional

Banana (Musa × paradisiaca L.) cultivation is one of the most important agricultural activities for many countries, and it is the primary fruit consume worldwide. Integrated soil management and fertilization programs aims to enhance soil fertility while maintaining crop yields. A large body of literature examined the changes in soil properties associated with different fertility regimens. Despite the critical role of the plant-associated microbiome in plant health and productivity, the effects of different agricultural management systems on microbial communities' response in banana are poorly understood.  This study reports the structure, diversity, and richness of the microbial community of the bulk soil, rhizosphere, and leaf of banana plants under organic and conventional management. Samples were obtained from two banana plantations located in the province of El Oro, Ecuador. The analysis was based on DNA sequencing of the V3-V4 region of the 16S rRNA gene for bacteria and the ITS2 region for fungi. Here, we found a significant effect of the management system in the bacterial and fungi community composition. In general terms, under a conventionally managed system, the richness and evenness of the bacterial and fungal community increased among the soil and rhizosphere compared to the organic farming system. Soil and rhizosphere under organic farming were associated with a higher relative abundance of Proteobacteria, Firmicutes, and Bacteroidetes and exhibited an overrepresentation of microbial genus know as plant growth-promoting, as well as genera involved in essential ecosystem processes. We also found that ASVs of the same genus respond differently to the two types of agricultural management on the soil and the rhizosphere. In comparison, the bacterial communities in the leaves were more similar in both types of management.  Understanding how long-term cropping management systems shift the microbial diversity and structure at the level of individual microbial taxa, such as presented in this research, can help to design farming systems that can maintain high profitability of the banana crops by stimulating growth-promoting bacteria and those responsible for the suppression of the soil-borne disease.El cultivo de banano (Musa × paradisiaca L.) es una de las actividades agrícolas más importantes para muchos países y es la principal fruta consumida mundialmente. La fertilización química es una de las prácticas más comunes utilizada para aumentar el rendimiento y productividad de los cultivos. Una gran cantidad de literatura examina los cambios en las propiedades del suelo asociados con diferentes regímenes de fertilización. A pesar del papel fundamental del microbioma en la salud y la productividad de las plantas, los efectos de los diferentes sistemas de gestión agrícola sobre las comunidades microbianas son poco estudiados. Este estudio informa la estructura, diversidad y riqueza de la comunidad microbiana del suelo, rizosfera y hoja de las plantas de banano bajo manejo orgánico y convencional. Se obtuvieron muestras de dos plantaciones bananeras ubicadas en El Oro, una de las provincias con mayor productividad bananera en Ecuador. El análisis se basó en la secuenciación de ADN de la región V3-V4 del gen del ARNr 16S para bacterias y la región ITS2 para hongos. Se encontró un efecto significativo del sistema de manejo en la composición de la comunidad bacteriana y fúngica. En términos generales, bajo un sistema de manejo convencional, la riqueza y uniformidad de la comunidad bacteriana y fúngica aumentó entre las muestras de suelo y rizosfera en comparación con el sistema de agricultura orgánica. El suelo y la rizosfera bajo agricultura orgánica se asociaron con una mayor abundancia relativa de Proteobacteria, Firmicutes y Bacteroidetes y exhibieron una sobrerrepresentación de géneros microbianos conocidos como promotores del crecimiento de plantas, así como géneros involucrados en procesos importantes del ecosistema. También encontramos que los ASV del mismo género responden diferente a los dos tipos de manejo agrícola en el suelo y la rizosfera. Mientras que las comunidades bacterianas en las hojas fueron más similares en ambos tipos de manejo. Comprender cómo los sistemas de gestión de cultivos a largo plazo modifican la diversidad y la estructura microbiana, como se presenta en esta investigación, puede ayudar a diseñar sistemas agrícolas que puedan mantener una alta rentabilidad de los cultivos de banano mediante la estimulación de bacterias promotoras del crecimiento y supresoras de las enfermedades transmitidas por el suelo

Combined searches for the production of supersymmetric top quark partners in proton-proton collisions at root s=13 TeV

A combination of searches for top squark pair production using proton-proton collision data at a center-of-mass energy of 13 TeV at the CERN LHC, corresponding to an integrated luminosity of 137 fb(-1) collected by the CMS experiment, is presented. Signatures with at least 2 jets and large missing transverse momentum are categorized into events with 0, 1, or 2 leptons. New results for regions of parameter space where the kinematical properties of top squark pair production and top quark pair production are very similar are presented. Depending on themodel, the combined result excludes a top squarkmass up to 1325 GeV for amassless neutralino, and a neutralinomass up to 700 GeV for a top squarkmass of 1150 GeV. Top squarks with masses from 145 to 295 GeV, for neutralino masses from 0 to 100 GeV, with a mass difference between the top squark and the neutralino in a window of 30 GeV around the mass of the top quark, are excluded for the first time with CMS data. The results of theses searches are also interpreted in an alternative signal model of dark matter production via a spin-0 mediator in association with a top quark pair. Upper limits are set on the cross section for mediator particle masses of up to 420 GeV

MUSiC : a model-unspecific search for new physics in proton-proton collisions at root s=13TeV

Results of the Model Unspecific Search in CMS (MUSiC), using proton-proton collision data recorded at the LHC at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1), are presented. The MUSiC analysis searches for anomalies that could be signatures of physics beyond the standard model. The analysis is based on the comparison of observed data with the standard model prediction, as determined from simulation, in several hundred final states and multiple kinematic distributions. Events containing at least one electron or muon are classified based on their final state topology, and an automated search algorithm surveys the observed data for deviations from the prediction. The sensitivity of the search is validated using multiple methods. No significant deviations from the predictions have been observed. For a wide range of final state topologies, agreement is found between the data and the standard model simulation. This analysis complements dedicated search analyses by significantly expanding the range of final states covered using a model independent approach with the largest data set to date to probe phase space regions beyond the reach of previous general searches.Peer reviewe

Measurement of prompt open-charm production cross sections in proton-proton collisions at root s=13 TeV

The production cross sections for prompt open-charm mesons in proton-proton collisions at a center-of-mass energy of 13TeV are reported. The measurement is performed using a data sample collected by the CMS experiment corresponding to an integrated luminosity of 29 nb(-1). The differential production cross sections of the D*(+/-), D-+/-, and D-0 ((D) over bar (0)) mesons are presented in ranges of transverse momentum and pseudorapidity 4 < p(T) < 100 GeV and vertical bar eta vertical bar < 2.1, respectively. The results are compared to several theoretical calculations and to previous measurements.Peer reviewe

Measurement of B-c(2S)(+) and B-c*(2S)(+) cross section ratios in proton-proton collisions at root s=13 TeV

Peer reviewe

Reconstruction of signal amplitudes in the CMS electromagnetic calorimeter in the presence of overlapping proton-proton interactions

A template fitting technique for reconstructing the amplitude of signals produced by the lead tungstate crystals of the CMS electromagnetic calorimeter is described. This novel approach is designed to suppress the contribution to the signal of the increased number of out-of-time interactions per beam crossing following the reduction of the accelerator bunch spacing from 50 to 25 ns at the start of Run 2 of the LHC. Execution of the algorithm is sufficiently fast for it to be employed in the CMS high-level trigger. It is also used in the offline event reconstruction. Results obtained from simulations and from Run 2 collision data (2015-2018) demonstrate a substantial improvement in the energy resolution of the calorimeter over a range of energies extending from a few GeV to several tens of GeV.Peer reviewe

Search for long-lived particles decaying to jets with displaced vertices in proton-proton collisions at root s=13 Te V

A search is presented for long-lived particles produced in pairs in proton-proton collisions at the LHC operating at a center-of-mass energy of 13 TeV. The data were collected with the CMS detector during the period from 2015 through 2018, and correspond to a total integrated luminosity of 140 fb(-1). This search targets pairs of long-lived particles with mean proper decay lengths between 0.1 and 100 mm, each of which decays into at least two quarks that hadronize to jets, resulting in a final state with two displaced vertices. No significant excess of events with two displaced vertices is observed. In the context of R-parity violating supersymmetry models, the pair production of long-lived neutralinos, gluinos, and top squarks is excluded at 95% confidence level for cross sections larger than 0.08 fb, masses between 800 and 3000 GeV, and mean proper decay lengths between 1 and 25 mm.Peer reviewe

Observation of tW production in the single-lepton channel in pp collisions at root s=13 TeV

A measurement of the cross section of the associated production of a single top quark and a W boson in final states with a muon or electron and jets in proton-proton collisions at root s = 13 TeV is presented. The data correspond to an integrated luminosity of 36 fb(-1) collected with the CMS detector at the CERN LHC in 2016. A boosted decision tree is used to separate the tW signal from the dominant t (t) over bar background, whilst the subleading W+jets and multijet backgrounds are constrained using data-based estimates. This result is the first observation of the tW process in final states containing a muon or electron and jets, with a significance exceeding 5 standard deviations. The cross section is determined to be 89 +/- 4 (stat) +/- 12 (syst) pb, consistent with the standard model.Peer reviewe

Search for top squark production in fully hadronic final states in proton-proton collisions at root s=13 TeV

A search for production of the supersymmetric partners of the top quark, top squarks, is presented. The search is based on proton-proton collision events containing multiple jets, no leptons, and large transverse momentum imbalance. The data were collected with the CMS detector at the CERN LHC at a center-of-mass energy of 13 TeV, and correspond to an integrated luminosity of 137 fb(-1). The targeted signal production scenarios are direct and gluino-mediated top squark production, including scenarios in which the top squark and neutralino masses are nearly degenerate. The search utilizes novel algorithms based on deep neural networks that identify hadronically decaying top quarks and W bosons, which are expected in many of the targeted signal models. No statistically significant excess of events is observed relative to the expectation from the standard model, and limits on the top squark production cross section are obtained in the context of simplified supersymmetric models for various production and decay modes. Exclusion limits as high as 1310 GeVare established at the 95% confidence level on the mass of the top squark for direct top squark production models, and as high as 2260 GeV on the mass of the gluino for gluino-mediated top squark production models. These results represent a significant improvement over the results of previous searches for supersymmetry by CMS in the same final state.Peer reviewe