Biology subjects

Sorger, Z.

Publications and source records attributed to Sorger, Z..

4 recordsLinked to original sources

bioRxiv2026

Infection of maize by Ustilago maydis remodels the phyllosphere microbiome and requires the activity of antimicrobial effectors

Plant-associated microbial communities play a critical role in plant health and disease resistance, but the mechanisms which reshape these communities during pathogen infection are poorly understood. In this study, we investigated how infection of maize by the smut fungus Ustilago maydis is functionally linked with the bacterial phyllosphere microbiome and explored the role of an antimicrobial effector GH25 in fungal infection. Using a combination of culture-dependent and culture-independent approaches, we compared the leaf microbiomes of infected and uninfected plants. We observed a significant increase in microbial abundance and pronounced shifts in community composition and identified distinct health-associated (HCom) and disease-associated (DCom) bacterial communities. To assess whether U. maydis directly manipulates the microbiome, we tested the antimicrobial activity of the antimicrobial effector GH25 against isolated strains. Notably, all HCom bacteria were sensitive to GH25 and co-inoculation of HCom bacteria with a U. maydis {Delta}gh25 knockout mutant significantly reduced fungal virulence. In contrast, DCom exhibited minimal sensitivity to U. maydis and did not affect the virulence of U. maydis {Delta}gh25. Genome-scale metabolic community modelling coupled with functional profiling revealed infection-associated shifts in predicted metabolic potential, consistent with U. maydis induced leaf tumors being strong sink tissues. Together, this work shows that U. maydis infection reshapes the maize phyllosphere microbiome through a combination of effector-mediated antimicrobial activity and host metabolic reprogramming.

microbiology↗

bioRxiv2025

Processing and release of the maize phytocytokine Zip1

Phytocytokines are endogenous peptides that modulate plant immunity outcomes, yet how their maturation and spatial deployment are controlled remains unclear. Here we show that the maize phytocytokine precursor PROZIP1 is controlled by a spatially separated, two-stage proteolytic pathway that mechanistically uncouples signal activation from extracellular attenuation. PROZIP1 associates with the endoplasmic reticulum and undergoes intracellular, arginine-dependent processing by type II metacaspases, generating a C-terminal PROZIP1 fragment (Ct-PROZIP1). This processing licenses PROZIP1 for export to the apoplast via an ER-Golgi-independent route. Proteomic mapping and mutational analyses identify arginine residues flanking the Zip1 peptide as critical for efficient processing and secretion. The calcium-dependent metacaspase ZmMC9 specifically processes PROZIP1, thereby efficiently generating the bioactive Ct-PROZIP1 fragment. In the apoplast, Ct-PROZIP1 is further processed by papain-like cysteine proteases and additional extracellular proteases, contributing to Zip1 turnover and signal clearance. While the free Zip1 peptide is detected at later stages, Ct-PROZIP appears to be the primary signaling entity in modulating pathogen-induced immune responses. Together, these findings demonstrate a previously unknown complexity in peptide signaling, suggesting a multilayered control of phytocytokine activity that provides spatial and temporal precision to disease modulation in maize.

plant biology↗

bioRxiv2025

GH25 lysozyme mediates tripartite interkingdom interactions and microbial competition on the plant leaf surface

Microbial communities inhabiting plants have emerged as crucial factors in regulating plant health and defense against disease-causing pathogens. The basidiomycete yeast Moesziomyces bullatus ex. Albugo on Arabidopsis (MbA) releases Glycoside Hydrolase 25 (GH25) protein which regulates the leaf microbiome by antagonizing an oomycete A. laibachii biotrophic pathogen MbA. Application of both MbA and GH25 protein rescued fresh shoot weight of A. thaliana upon A. laibachii infection, showing its potential in plant protection. Tripartite interaction assays did not reveal antagonistic activity of GH25 towards other plant pathogenic oomycetes or fungi besides A. laibachii. We identified a core set of bacteria are closely associated with A. laibachii and established that GH25 inhibits members of this core group. Among A. laibachii-associated bacteria that were inhibited by GH25, Curtobacterium sp. could override the inhibition of A. laibachii by MbA. We describe a tripartite antagonistic interaction in which bacterium and oomycete protect each other from growth inhibition by MbA. Curtobacterium sp., in turn, exhibits specific inhibition of A. laibachii-associated bacteria that are not targeted by MbA but themselves antagonize A. laibachii. Our study reveals an inter-kingdom interaction network in which a GH25 lysozyme shapes the antagonistic relationship between yeast, a pathogenic oomycete and an oomycete-associated bacterium.

microbiology↗

bioRxiv2024

Quantitative detection of plant signaling peptides utilizing ELISA

Plant signaling peptides, also known as phytocytokines, are involved in a number of signaling mechanisms, including cell-to-cell communication during plant development and immunity. The detection of small peptides in plant tissues is challenging and often relies on time-consuming and cost-intensive approaches. Here, we present an ELISA-based assay as a rapid and cost-effective method for the detection of naturally released peptides in plant tissues. Our ELISA-based method was developed to detect Zip1, a 17-amino-acid phytocytokine derived from Zea mays that elicits salicylic acid signaling in maize leaves. Using a custom peptide-antibody, we designed an experimental pipeline to achieve peptide specificity, selectivity and sensitivity allowing the detection of the Zip1 peptide in complex biological samples. As a proof of concept, we transfected maize protoplasts to overexpress the precursor molecule PROZIP1 and treated maize leaves with salicylic acid to induce native PROZIP1 expression and Zip1 release. Using ELISA, we were able to quantify native Zip1 signals with a detection limit in the nanogram range, which allowed us to detect different Zip1-containing peptides in plant material. This method can be adapted for the detection and quantification of a variety of plant signaling peptides.

plant biology↗