Biology subjects

van Kan, J. A. L.

Publications and source records attributed to van Kan, J. A. L..

2 recordsLinked to original sources

bioRxiv2020

Convergent evolution of distinct immune sensor systems for fungal polygalacturonases in Brassicaceae

Plant pattern recognition receptors (PRRs) facilitate recognition of microbial surface patterns and mediate activation of plant immunity. Arabidopsis thaliana RLP42, a leucine-rich repeat (LRR) receptor protein (LRR-RP), senses fungal endopolygalacturonases (PGs) through a ternary complex comprising RLP42, the adapter kinase SOBIR1, and SERK proteins. Several fungal PGs harbor a conserved 9-amino acid fragment pg9(At), which is sufficient to activate RLP42-dependent plant immunity. Domain swap experiments using RLP42 and paralogous RLP40 sequences revealed a dominant role of the island domain (ID) for ligand binding and PRR complex assembly. Involvement of the ID in plant receptor function is reminiscent of plant phytosulfokine (PSK) perception through the receptor, PSKR, a LRR receptor kinase. Sensitivity to pg9(At), which is restricted to A. thaliana, exhibits notable accession specificity as active RLP42 alleles were found in only 16 of 52 accessions tested. Arabidopsis arenosa and Brassica rapa, two Brassicaceae species closely related to A. thaliana, perceive plant immunogenic PG fragments pg20(Aa) or pg36(Bra), which are distinct from pg9(At). Our study unveils unprecedented complexity and dynamics of PG pattern recognition receptor evolution within a single plant family. PG perception systems may have evolved rather independently as a result of convergent evolution even among closely related species.

plant biology↗

bioRxiv2020

Red-light imaging for programmed cell death visualization and quantification in plant-pathogen interactions

Studies on plant-pathogen interactions often involve monitoring disease symptoms or responses of the host plant to pathogen-derived immunogenic patterns, either visually or by staining the plant tissue. Both these methods have limitations with respect to resolution, reproducibility and the ability to quantify the results. In this study we show that red light detection in a multi-purpose fluorescence imaging system that is probably available in many labs can be used to visualize plant tissue undergoing cell death. Red light emission is the result of chlorophyll fluorescence upon thylakoid membrane disassembly during the development of a programmed cell death process. The activation of programmed cell death can occur either during a hypersensitive response to a biotrophic pathogen or an apoptotic cell death triggered by a necrotrophic pathogen. Quantifying the intensity of the red light signal enables to evaluate the magnitude of programmed cell death and provides a non-invasive readout of the plant immune response in a faster and safer manner as compared to chemical staining methodologies previously developed. This application can be implemented to screen for differences in symptom severity in plant-pathogen interactions, and to visualize and quantify in a sensitive and objective manner the intensity of a plant response upon perception of a given immunological pattern. We illustrate the utility and versatility of the method using diverse immunogenic patterns and pathogens.

plant biology↗