Understanding the ternary interaction of crop plants, fungal pathogens, and rhizobacteria in response to global...

Climate change is altering the equilibrium of the Earth's biosphere, imposing unpredictable survival dynamics on terrestrial organisms. This includes the intricate interactions between fungal pathogens and crop plants, which are pivotal for global food security. Rising temperatures are expected to exacerbate the prevalence of crop-pathogenic fungi worldwide, yet research on how crops respond to this imminent threat remains limited. Here, we identified predominant potential pathogens and antagonistic bacteria in vegetable fields in Shandong Province, China, revealing the near-ubiquitous presence of Fusarium oxysporum and Bacillus species in sampled soils of cucumber, tomato, chili, and ginger. Through simulated warming experiments within a temperature range of 20-40 °C and an experimental period of 3 days, we investigated the ternary interaction among vegetables and isolated F. oxysporum strain 05, and Bacillus sp. strain 31. Elevated temperatures enhanced F. oxysporum biomass and virulence, yet also stimulated vegetables to allocate more nutrients via root exudates. This enriched rhizospheric antagonistic Bacillus populations, it also boosted the expression of antifungal lipopeptide biosynthetic genes (bamb and ItuA) and auxin production in Bacillus sp. strain 31. This enrichment promoted plant growth and maintained a relatively stable level of pathogenic fungi. Our study unveiled a nuanced and complex interplay among crop plants, fungal pathogens, and rhizobacteria, that could inform future agricultural practices, and advance our understanding of crop survival strategies to bolster crop resilience and safeguard global food security under ongoing climate change.