Biology subjects

Andersen, C. B.

Publications and source records attributed to Andersen, C. B..

3 recordsLinked to original sources

bioRxiv2026

Building Bridges Belowground: Pythium oligandrum En-hances Rhizosphere Network Connectivity

Biological control agents (BCAs) offer a potential sustainable alternative to fungicides for crop dis-ease management, but their effects on resident plant microbiomes and microbial interactions remain poorly understood. Here, we investigated the effects of the BCA Pythium oligandrum on disease con-trol and the rhizosphere microbiome of starch potato cv. Kuras in a field trial. We compared a labora-tory strain and a commercial formulation (Polygandron) with commonly used fungicides during early blight development. The laboratory strain suppressed early blight at plant senescence, but this effect did not persist until harvest, whereas fungicide treatment provided near-complete disease suppression throughout the growing season. P. oligandrum caused transient changes in rhizosphere fungal com-munity composition at flowering, while bacterial community richness varied among sampling times in untreated controls. However, bacterial co-occurrence network analysis revealed pronounced treat-ment-specific changes in microbial connectivity. Application of the laboratory strain increased net-work connectivity, resulting in almost a threefold increase in mean degree and greater interconnected-ness among bacterial taxa. In contrast, Polygandron and fungicide treatments reduced mean degree, indicating reduced connectivity within the bacterial network. Fungicide treatment additionally altered network organisation, including increased betweenness centrality and changes in modularity. Togeth-er, our results show that P. oligandrum can modify microbial interactions in the potato rhizosphere without substantially altering overall bacterial community composition, highlighting the value of in-tegrating microbial network structure with community-level analyses when evaluating the ecological effects of BCAs.

microbiology↗

bioRxiv2025

Post-Domestication selection of MKK3 Shaped Seed Dormancy and End-Use Traits in Barley

Anthropogenic selection of grain traits such as dormancy has shaped the developmental trajectories of crop plants (1). In cereals, shortening dormancy provides rapid and even post-harvest germination, but increases the risk of weather-induced pre-harvest sprouting (PHS) with harvest losses estimated at beyond 1 billion USD a year (2, 3, 4). Our understanding of how, why, when and where diversification of cereal dormancy arose is fragmentary. Here, we show in the founder cereal crop barley (Hordeum vulgare) that the Mitogen-Activated Protein Kinase (MAPK) pathway regulates dormancy primarily through a mosaic of locus haplotypes comprising copy-number variation and inherent kinase activity of Mitogen-activated protein kinase kinase 3 (MKK3). We provide evidence supporting the historical selection of specific MKK3 haplotypes that shape dormancy levels according to changing climatic pressures. Understanding the regulatory landscape of MKK3 provides a genetic framework to balance short grain dormancy and PHS-avoidance during a period of rapid climate change.

plant biology↗

bioRxiv2021

A family of cell wall transglutaminases is essential for appressorium development and pathogenicity in Phytophthora infestans

Transglutaminases (TGases) are enzymes highly conserved among prokaryotic and eukaryotic organisms, where their role is to catalyse protein cross-linking. One of the putative TGases of Phytophthora infestans has previously been shown to be localised to the cell wall. Based on sequence similarity we were able to identify six more genes annotated as putative TGases and show that these seven genes group together in phylogenetic analysis. All of the seven proteins are predicted to contain transmembrane helices and both a TGase domain and a MANSC domain, the latter of which was previously shown to play a role in protein stability. Chemical inhibition of transglutaminase activity and silencing of the entire family of the putative cell wall TGases are both lethal to P. infestans indicating the importance of these proteins in cell wall formation and stability. The intermediate phenotype obtained with lower drug concentrations and less efficient silencing displays a number of deformations to germ tubes and appressoria. Both chemically treated and silenced lines show lower pathogenicity than the wild type in leaf infection assays. Finally, we show that appressoria of P. infestans possess the ability to build up turgor pressure and that this ability is decreased by chemical inhibition of TGases.

molecular biology↗