Fair-weather friends: Priority determines disease outcomes in an agonistic multi-pathogen crop pathosystem

In both plant and animal pathosystems, the host is typically challenged by more than one pathogen simultaneously. Parastagonospora nodorum and Pyrenophora tritici-repentis frequently co-infect the same leaves, yet their interaction dynamics remain poorly understood due to limitations in species-specific pathogen quantification. We investigated how arrival order and host resistance affect disease outcomes during co-infection.
We developed a duplex digital PCR assay targeting single copy α-tubulin genes to enable directly comparable biomass quantification of both pathogens. Field surveys and controlled sequential inoculation experiments were conducted across wheat cultivars with differential resistance to evaluate priority effects on pathogen proliferation and disease severity.
Field surveys revealed a clear majority of symptomatic infections involved both pathogens, with individual pathogen biomass significantly elevated under co-infection, particularly in moderately resistant cultivars...., , # Fair-weather friends. Priority determines disease outcomes in an agonistic multi-pathogen crop pathosystem

**# Data from:** Lenzo_et_al_dryad.tar.gz

## Description

This dataset contains data and analysis scripts for all figures presented in Lenzo et al. (2025). The study investigates co-infection dynamics between ***Parastagonospora nodorum*** and ***Pyrenophora tritici-repentis***, the causal agents of septoria nodorum blotch (SNB) and tan spot (TS) of wheat. Using a novel digital PCR-based quantification method targeting the α-tubulin gene, this work reveals asymmetric priority effects where pathogen arrival order determines infection outcomes and can overcome host resistance. Field surveys revealed up to two in three symptomatic infections involved both pathogens, with controlled experiments demonstrating that ***P. tritici-repentis*** establishment facilitates subsequent ***P. nodorum*** colonization and breakdown of host resistance, while ***P. nodorum*** priority establishmen...,