Pathogen-induced activation of disease-suppressive functions in the endophytic root microbiome

Microorganisms living inside plants can promote plant growth and health, but their genomic and functional diversity remain largely elusive. Here, metagenomics and network inference show that fungal infection of plant roots enriched for Chitinophagaceae and Flavobacteriaceae in the root endosphere and for chitinase genes and various unknown biosynthetic gene clusters encoding the production of nonribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs). After strain-level genome reconstruction, a consortium of Chitinophaga and Flavobacterium was designed that consistently suppressed fungal root disease. Site-directed mutagenesis then revealed that a previously unidentified NRPS-PKS gene cluster from Flavobacterium was essential for disease suppression by the endophytic consortium. Our results highlight that endophytic root microbiomes harbor a wealth of as yet unknown functional traits that, in concert, can protect the plant inside out.Microbial Biotechnolog

Measurements of production cross sections of polarized same-sign W boson pairs in association with two jets in proton-proton collisions at s=13 TeV

The first measurements of production cross sections of polarized same-sign W±W±boson pairs in proton-proton collisions are reported. The measurements are based on a data sample collected with the CMS detector at the LHC at a center-of-mass energy of 13TeV, corresponding to an integrated luminosity of 137fb−1. Events are selected by requiring exactly two same-sign leptons, electrons or muons, moderate missing transverse momentum, and two jets with a large rapidity separation and a large dijet mass to enhance the contribution of same-sign W±W±scattering events. An observed (expected) 95% confidence level upper limit of 1.17 (0.88)fbis set on the production cross section for longitudinally polarized same-sign W±W±boson pairs. The electroweak production of same-sign W±W±boson pairs with at least one of the Wbosons longitudinally polarized is measured with an observed (expected) significance of 2.3 (3.1) standard deviations.SCOAP

The carbon cycle and atmospheric carbon dioxide

International audienc

Plant quality and primary productivity modulate plant biomass responses to the joint effects of grazing and fertilization in a mesic grassland

Questions: Human activities are increasing the density of domestic grazers and global nutrient loads, modifying the main determinants of vegetation community dynamics. Grazing (top-down control) and nutrient availability (bottom-up control) may interactively modify plant biomass, which is particularly important in grasslands devoted to livestock production. Here, we aim to understand the interactive effects of grazing and fertilization on grassland plant biomass. We hypothesized that the joint effects of nutrient addition and domestic grazing on above-ground plant biomass are not additive, but they modify each other through changes in ground-level light, leaf nutritional quality, above-ground net primary productivity (ANPP), and below-ground plant allocation. Location: Flooding Pampa (Buenos Aires, Argentina). Methods: We carried out a factorial experiment of grazing exclusion and fertilization with nitrogen, phosphorus, and potassium + micronutrients during ​several years in a mesic grassland devoted to livestock production. Results: After four years, grazing reduced live above-ground plant biomass by 52%, and when combined with fertilization this reduction was 70%. Nutrient addition in the grazed grassland increased ANPP and leaf nutrient concentration. These changes in turn intensified grazing pressure and cattle’s plant consumption. By contrast, fertilization did not produce any significant effect on plant biomass or ANPP inside the exclosures, where ground-level light was low. A structural equation model revealed that the increase in ANPP fostered above-ground and reduced below-ground plant biomass. Conclusions: This is the first study conducted in the Pampas grasslands that evaluated the effect of cattle grazing and fertilization on plant communities under field conditions over several years. Grazing and nutrient addition synergistically controlled grassland plant biomass, as the reduction in above-ground biomass by cattle consumption was greater in fertilized plots. Our results provided empirical evidence that leaf nitrogen and ANPP modulated plant biomass dynamics in grasslands devoted to livestock production in the context of increased nutrient loads in terrestrial ecosystems.Fil: Campana, María Sofía. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Yahdjian, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentin