Cryptic species continue to be uncovered in many fish taxa, posing challenges for fisheries conservation and management. In Sardinella gibbosa, previous investigations revealed subtle intra-species ...variations, resulting in numerous synonyms and a controversial taxonomy for this sardine. Here, we tested for cryptic diversity within S. gibbosa using genetic data from two mitochondrial and one nuclear gene regions of 248 individuals of S. gibbosa, collected from eight locations across the Philippine archipelago. Deep genetic divergence and subsequent clustering was consistent across both mitochondrial and nuclear markers. Clade distribution is geographically limited: Clade 1 is widely distributed in the central Philippines, while Clade 2 is limited to the northernmost sampling site. In addition, morphometric analyses revealed a unique head shape that characterized each genetic clade. Hence, both genetic and morphological evidence strongly suggests a hidden diversity within this common and commercially-important sardine.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In this article, we are interested in the asymptotic analysis of a finite volume scheme for one-dimensional linear kinetic equations, with either a Fokker-Planck or linearized BGK collision operator. ...Thanks to appropriate uniform estimates, we establish that the proposed scheme is Asymptotic-Preserving in the diffusive limit. Moreover, we adapt to the discrete framework the hypocoercivity method proposed by J. Dolbeault, C. Mouhot, and C. Schmeiser Trans. Amer. Math. Soc. 367, no. 6 (2015) to prove the exponential return to equilibrium of the approximate solution. We obtain decay rates that are uniformly bounded in the diffusive limit. Finally, we present an efficient implementation of the proposed numerical schemes and perform numerous numerical simulations assessing their accuracy and efficiency in capturing the correct asymptotic behaviors of the models.
The primary objective of this study was to identify the molecular signals present in arbuscular mycorrhizal (AM) germinated spore exudates (GSEs) responsible for activating nuclear Ca2+ spiking in ...the Medicago truncatula root epidermis.
Medicago truncatula root organ cultures (ROCs) expressing a nuclear-localized cameleon reporter were used as a bioassay to detect AM-associated Ca2+ spiking responses and LC-MS to characterize targeted molecules in GSEs.
This approach has revealed that short-chain chitin oligomers (COs) can mimic AM GSE-elicited Ca2+ spiking, with maximum activity observed for CO4 and CO5. This spiking response is dependent on genes of the common SYM signalling pathway (DMI1/DMI2) but not on NFP, the putative Sinorhizobium meliloti Nod factor receptor. A major increase in the CO4/5 concentration in fungal exudates is observed when Rhizophagus irregularis spores are germinated in the presence of the synthetic strigolactone analogue GR24. By comparison with COs, both sulphated and nonsulphated Myc lipochito-oligosaccharides (LCOs) are less efficient elicitors of Ca2+ spiking in M. truncatula ROCs.
We propose that short-chain COs secreted by AM fungi are part of a molecular exchange with the host plant and that their perception in the epidermis leads to the activation of a SYM-dependent signalling pathway involved in the initial stages of fungal root colonization.
•Research has started to uncover that elements thought to be exclusive to symbiosis are also affected in pathogenic interactions.•Mechanisms of endophytic microbe colonisation intersect with plant ...development.•Some filamentous pathogen effectors interfere with plant development mechanisms.
Plant roots are host to a multitude of filamentous microorganisms. Among these, arbuscular mycorrhizal fungi provide benefits to plants, while pathogens trigger diseases resulting in significant crop yield losses. It is therefore imperative to study processes which allow plants to discriminate detrimental and beneficial interactions in order to protect crops from diseases while retaining the ability for sustainable bio-fertilisation strategies. Accumulating evidence suggests that some symbiosis processes also affect plant–pathogen interactions. A large part of this overlap likely constitutes plant developmental processes. Moreover, microbes utilise effector proteins to interfere with plant development. Here we list relevant recent findings on how plant–microbe interactions intersect with plant development and highlight future research leads.
Plant LysM proteins control the perception of microbial-derived N-acetylglucosamine compounds for the establishment of symbiosis or activation of plant immunity. This raises questions about how ...plants, and notably legumes, can differentiate friends and foes using similar molecular actors and whether any receptors can intervene in both symbiosis and resistance.
To study this question, nfp and lyk3 LysM-receptor like kinase mutants of Medicago truncatula that are affected in the early steps of nodulation, were analysed following inoculation with Aphanomyces euteiches, a root oomycete. The role of NFP in this interaction was further analysed by overexpression of NFP and by transcriptome analyses.
nfp, but not lyk3, mutants were significantly more susceptible than wildtype plants to A. euteiches, whereas NFP overexpression increased resistance. Transcriptome analyses on A. euteiches inoculation showed that mutation in the NFP gene led to significant changes in the expression of c. 500 genes, notably involved in cell dynamic processes previously associated with resistance to pathogen penetration. nfp mutants also showed an increased susceptibility to the fungus Colletotrichum trifolii.
These results demonstrate that NFP intervenes in M. truncatula immunity, suggesting an unsuspected role for NFP in the perception of pathogenic signals.
Streptomyces spp. constitute a major clade of the phylum Actinobacteria. These Gram-positive, filamentous prokaryotes are ubiquitous in soils and marine sediments, and are commonly found in the ...rhizosphere or inside plant roots. Plant-interacting Streptomyces have received limited attention, in contrast to Streptomyces spp. extensively investigated for decades in medicine given their rich potential for secondary metabolite biosynthesis. Recent genomic, metabolomic, and biotechnological advances have produced key insights into Streptomyces spp., paving the way to the use of their metabolites in agriculture. In this Opinion article we propose how Streptomyces spp. could dominate future aspects of crop nutrition and protection. Risks and benefits of the use of these microorganisms in agriculture are also discussed.
One of the current major scientific challenges is to ensure food security for a growing global population, with the assistance of safe and sustainable agronomic solutions.
Microbial communities of agronomic soils and endophytic microorganisms were largely ignored during the first green revolution, in the 1960s, and the beneficial functions for the crops fulfilled by these microbes have been taken over in recent decades by chemical applications. However, recent advances in omics and synthetic biology are now creating new opportunities to devise strategies aiming at reintroducing microbial genera into our agricultural system.
•We measured vaccine efficacy against SARS-CoV-2 in France in Winter 2021-2022.•Vaccine efficacy against infection by the Omicron variant was low and fast declining.•Vaccine efficacy was higher for ...mixed vaccine schemes.•Efficacy against Omicron infection was negative in some areas.•Negative efficacy was explained by less-risk contacts of unvaccinated individuals.
We aimed to quantify how the vaccine efficacy of BNT162b2, messenger RNA-1273, AD26.COV2-S, and ChAdOx1 nCoV-19 against detected infection by the SARS-CoV-2 Delta and Omicron variants varied by time since the last dose, vaccine scheme, age, and geographic areas.
We analyzed 3,261,749 community polymerase chain reaction tests conducted by private laboratories in France from December 2021 to March 2022 with a test-negative design comparing vaccinated to unvaccinated individuals.
Efficacy against detected infection by Delta was 89% (95% confidence interval, 86-91%) at 2 weeks, down to 59% (56-61%) at 26 weeks and more after the second dose. Efficacy against Omicron was 48% (45-51%) at 2 weeks, down to 4% (2-5%) at 16 weeks after the second dose. A third dose temporarily restored efficacy. Efficacy against Omicron was lower in children and the elderly. Geographical variability in efficacy may reflect variability in the ratio of the number of contacts of vaccinated vs unvaccinated individuals. This ratio ranged from 0 to +50% across departments and correlated with the number of restaurants and bars per inhabitant (beta = 15.0 0.75-29, P-value = 0.04), places that only vaccinated individuals could access in the study period.
SARS-CoV-2 vaccines conferred low and transient protection against Omicron infection.
Spectral methods, thanks to their high accuracy and the possibility to use fast algorithms, represent an effective way to approximate the collisional kinetic equations of Boltzmann type, such as the ...Boltzmann-Nordheim equation. This equation, modeled on the seminal Boltzmann equation, describes using a statistical physics formalism the time evolution of a gas composed of bosons or fermions. Using the spectral-Galerkin algorithm introduced in Filbet et al. (2012) 11, together with some novel parallelization techniques, we investigate some of the conjectured properties of the large time behavior of the solutions to this equation. In particular, we are able to observe numerically both Bose-Einstein condensation and Fermi-Dirac relaxation.
•Efficient parallel MPI-based implementation of the Fast Fourier spectral method for the quantum Boltzmann equation.•Use of the rescaling velocity method to improve the accuracy by adapting the grid to the support of the solutions.•Able to accurately reproduce some of the fine mathematical properties of the equation, reminded in Section 1.2.•Fermi-Dirac saturation and Bose-Einstein condensation are highlighted for the first time in the full 3D space.
Pythium oligandrum
is a soil-borne oomycete associated with rhizosphere and root tissues. Its ability to enhance plant growth, stimulate plant immunity and parasitize fungal and oomycete preys has ...led to the development of agricultural biocontrol products. Meanwhile, the effect of
P. oligandrum
on mutualistic interactions and more generally on root microbial communities has not been investigated. Here, we developed a biological system comprising
P. oligandrum
interacting with two legume plants,
Medicago truncatula
and
Pisum sativum. P. oligandrum
activity was investigated at the transcriptomics level through an RNAseq approach, metabolomics and finally metagenomics to investigate the impact of
P. oligandrum
on root microbiota. We found that
P. oligandrum
promotes plant growth in these two species and protects them against infection by the oomycete
Aphanomyces euteiches
, a devastating legume root pathogen. In addition,
P. oligandrum
up-regulated more than 1000 genes in
M. truncatula
roots including genes involved in plant defense and notably in the biosynthesis of antimicrobial compounds and validated the enhanced production of
M. truncatula
phytoalexins, medicarpin and formononetin. Despite this activation of plant immunity, we found that root colonization by
P. oligandrum
did not impaired symbiotic interactions, promoting the formation of large and multilobed symbiotic nodules with
Ensifer meliloti
and did not negatively affect the formation of arbuscular mycorrhizal symbiosis. Finally, metagenomic analyses showed the oomycete modifies the composition of fungal and bacterial communities. Together, our results provide novel insights regarding the involvement of
P. oligandrum
in the functioning of plant root microbiota.
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