Publications by authors named "Pieterse C"

Potato vigour, the growth potential of seed potatoes, is a key agronomic trait that varies significantly across production fields due to factors such as genetic background and environmental conditions. Seed tuber microbiomes are thought to influence plant health and crop performance, yet the precise relationships between microbiome composition and potato vigour remain unclear. Here we conducted microbiome sequencing on seed tuber eyes and heel ends from 6 potato varieties grown in 240 fields.

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  • Potato cultivation in Ecuador's Andes, particularly the Superchola cultivar, accounts for 60% of the country's potato production, with significant observations made from November 2022 to January 2023 related to stem lesions on these plants.
  • An investigation of symptomatic plants led to the isolation of 14 bacterial strains, with one (M3) identified as pathogenic, causing lesions on potato tubers and stems.
  • Pathogenicity tests confirmed that only isolate M3 induced disease symptoms in healthy potato plants using specific inoculation techniques.
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  • The plant hormone abscisic acid (ABA) plays a key role in regulating plant development and stress responses by triggering a complex gene regulatory network involving many transcription factors (TFs) and genes.
  • An RNA-seq time series identified 7151 differentially expressed genes in response to ABA treatment, which were organized into 44 coexpressed modules responsible for various biological functions.
  • The study further analyzed TF regulation and interaction within the ABA gene regulatory network, highlighting the significance of the bZIP TF family and identifying GT3a as a positive regulator of drought tolerance, validated by drought assays.
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Plants have coevolved together with the microbes that surround them and this assemblage of host and microbes functions as a discrete ecological unit called a holobiont. This review outlines plant-driven assembly of disease-suppressive microbiomes. Plants are colonized by microbes from seed, soil, and air but selectively shape the microbiome with root exudates, creating microenvironment hot spots where microbes thrive.

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  • Potato seed tubers carry soil-borne microbes that can impact the following season's plants, and this study explored how these microbial communities are passed from seed tubers to the new plants.
  • Researchers found that the production field and potato genotype significantly influenced the microbiome's composition, which remained distinguishable even after winter storage, although there was minimal vertical transmission of field-specific microbes (less than 0.2%) to the new plants.
  • The study concluded that the original microbiome of seed tubers plays a critical role in the health of subsequent plants, indicating that these microbial communities deserve more attention in agricultural practices.
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Hyaloperonospora arabidopsidis (Hpa) is an obligately biotrophic downy mildew that is routinely cultured on Arabidopsis thaliana hosts that harbour complex microbiomes. We hypothesized that the culturing procedure proliferates Hpa-associated microbiota (HAM) in addition to the pathogen and exploited this model system to investigate which microorganisms consistently associate with Hpa. Using amplicon sequencing, we found nine bacterial sequence variants that are shared between at least three out of four Hpa cultures in the Netherlands and Germany and comprise 34% of the phyllosphere community of the infected plants.

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Intercellular signalling is an indispensable part of multicellular life. Understanding the commonalities and differences in how signalling molecules function in two remote branches of the tree of life may shed light on the reasons these molecules were originally recruited for intercellular signalling. Here we review the plant function of three highly studied animal intercellular signalling molecules, namely glutamate, γ-aminobutyric acid (GABA), and melatonin.

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Growth- and health-promoting bacteria can boost crop productivity in a sustainable way. Pseudomonas simiae WCS417 is such a bacterium that efficiently colonizes roots, modifies the architecture of the root system to increase its size, and induces systemic resistance to make plants more resistant to pests and pathogens. Our previous work suggested that WCS417-induced phenotypes are controlled by root cell-type-specific mechanisms.

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Competition for iron is an important factor for microbial niche establishment in the rhizosphere. Pathogenic and beneficial symbiotic bacteria use various secretion systems to interact with their hosts and acquire limited resources from the environment. Bacillus spp.

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Iron (Fe) plays a central role in the vital processes of a plant. The Fe status of a plant influences growth and immunity, but it also dictates interactions of roots with soil microbiota through the production of Fe mobilizing, antimicrobial fluorescent phenolic compounds called coumarins. To adapt to low Fe availability in the soil, plants deploy an efficient Fe deficiency response.

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Despite the numerous benefits plants receive from probiotics, maintaining consistent results across applications is still a challenge. Cultivation-independent methods associated with reduced sequencing costs have considerably improved the overall understanding of microbial ecology in the plant environment. As a result, now, it is possible to engineer a consortium of microbes aiming for improved plant health.

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Plants deposit photosynthetically-fixed carbon in the rhizosphere, the thin soil layer directly around the root, thereby creating a hospitable environment for microbes. To manage the inhabitants of this nutrient-rich environment, plant roots exude and dynamically adjust microbe-attracting and -repelling compounds to stimulate specific members of the microbiome. Previously, we demonstrated that foliar infection of Arabidopsis thaliana by the biotrophic downy mildew pathogen Hyaloperonospora arabidopsidis (Hpa) leads to a disease-induced modification of the rhizosphere microbiome.

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  • * This study focused on Pieris butterflies' oviposition preferences across 350 Arabidopsis plant variations and identified genes WRKY42 and AOC1 influencing these choices.
  • * Results showed that while WRKY42 strongly affected butterfly oviposition preferences, its presence led to poor performance of caterpillars, highlighting how plant traits can impact both insect behavior and offspring survival.
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Fear of dental treatment is a common phenomenon. Every oral health care provider will have to treat a patient with this fear one day. Adequate diagnostics are essential for a correct assessment of the level of fear and how an anxious patient can best be helped.

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A patient with extreme fear of dental treatment and a history of sexual abuse as well presented at a Centre for Special Care Dentistry. A dentist specializing in dental anxiety and a clinical psychologist worked closely together during intake and treatment phases. The comorbid PTSS appeared to hamper the exposure therapy.

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In the months leading up to this special on 'dental anxiety', an online survey was conducted on various aspects of the treatment of anxious patients. This survey was completed by 128 people, of whom approximately one third were men and two thirds were women. The results show that more than half of the respondents feel they haven't learned enough about treating anxious patients during the training.

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One century after the first report of Dutch elm disease (DED), there is still no practical solution for this problem threatening European and American elms (Ulmus spp.). The long breeding cycles needed to select resistant genotypes and the lack of efficient treatments keep disease incidence at high levels.

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Osteoclasts are large, multinucleated cells that are responsible for the resorption of bone. Bone degenerative diseases, such as osteoporosis, are characterized by overactive osteoclasts. Receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL) binding to its receptor on osteoclast precursors will trigger osteoclast formation and resorption.

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  • Researchers demonstrated that harmful bacteria, Pseudomonas protegens, can evolve into beneficial mutualists within six months in the presence of Arabidopsis thaliana plants.
  • This evolution is driven by enhanced competitiveness for nutrients and better resistance to plant-produced antimicrobial substances, particularly scopoletin.
  • Mutations in the GacS/GacA regulatory system were linked to the bacteria’s increased fitness, highlighting how quickly these microbes can adapt to support plant growth while reducing negative effects.
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We investigated the photoionization and fragmentation of isolated metal protoporphyrin IX cations (MPPIX with M=Fe, Co, Zn) by means of vacuum-ultraviolet (VUV) action spectroscopy in the energy range of 8.5-35 eV. Experiments were carried out in the gas phase by interfacing an electrospray ionization tandem mass spectrometer with a synchrotron beamline.

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  • Trichoderma fungi release volatile compounds (VCs) that help Arabidopsis plants activate a defense mechanism called induced systemic resistance (ISR) against various pathogens.
  • The transcription factor MYB72 plays a crucial role in both ISR and responses to iron deficiency, while nitric oxide (NO) is important for regulating MYB72 during iron deficiency but its role in ISR triggered by Trichoderma VCs was previously unknown.
  • In experiments, applying Trichoderma VCs produced a surge of NO in plant roots, and blocking NO decreased MYB72 expression and compromised the ISR response against the leaf pathogen Botrytis cinerea, confirming that root NO signaling is essential for effective defense activation.
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Beneficial plant root-associated microorganisms carry out a range of functions that are essential for plant performance. Establishment of a bacterium on plant roots, however, requires overcoming several challenges, including competition with neighboring microorganisms and host immunity. Forward and reverse genetics have led to the identification of mechanisms that are used by beneficial microorganisms to overcome these challenges, such as the production of iron-chelating compounds, the formation of strong biofilms, or the concealment of characteristic microbial molecular patterns that trigger the host immune system.

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