Keystone Pseudomonas species in the wheat phyllosphere microbiome mitigate Fusarium head blight by altering host pH

Xu et al., 2025

Phyllosphere microbiota play crucial roles in supporting host performance. However, the dynamic changes of phyllosphere-associated microbiome during pathogen infections and their impacts on plant health remain unknown. Here, we found phyllosphere microbes can mitigate wheat Fusarium head blight (FHB), a severe disease caused by Fusarium graminearum (F. graminearum) pathogen that promotes infection by inducing host alkalinization. Using wheat head microbial community profiling and metatranscriptomics, we found Pseudomonas spp. significantly enriched on infected wheat heads. Through isolating 595 bacterial strains from infected wheat heads—including 196 Pseudomonas isolates—we identified certain enriched Pseudomonas isolates capable of producing organic acids that counteract pathogen-induced pH upshift. In vitro experiments confirm the selective promotion of specific host-acidifying Pseudomonas in wheat heads. Field trials confirmed that host-acidifying Pseudomonas strains effectively controlled FHB. These findings highlight the pivotal role of plant-beneficial microbes in host pH regulation and offer innovative avenues for sustainable plant disease control.

https://www.cell.com/cell-host-microbe/fulltext/S1931-3128%2825%2900450-0

Plant-plant nitrogen transfer is prevalent in a semi-arid shrubland and affects the foliar N content of recipient plants

González-Díaz & Montesinos-Navarro

In dry ecosystems, plants cope with limited nutrients such as nitrogen (N), which is vital for growth. While nitrogen sharing between plants is known in agriculture, it is less understood in natural, semi-arid environments.

We studied nitrogen transfer between plants in a semi-arid shrubland in Spain and how this affects the nutrition of the neighbours. Using a stable isotope of nitrogen (¹⁵N), we labelled donor plants and tracked its movement to nearby plants over more than a year.

Nitrogen transfer was widespread: over 70% of neighbouring plants received nitrogen, most within a week of labelling. N transfer started in less than a week, and reached the maximum values approximately 60 days after labelling, getting back to pre-labelling values after 120 days. Repeated pulses increased both the transfer magnitude and the leaf nitrogen content of receiver plants. These results show that nitrogen exchange among plants is common in semi-arid shrublands and may help species coexist and thrive in nutrient-poor environments.

https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2435.70241

Rhizobium tropici Metabolites Induce Defence-Related Genes and Promote Sclerotinia Sclerotiorum Stem Rot Control in Chickpeas

de Sousa et al., 2025

Brazil has seen a steady increase in domestic chickpea production, and the crop is expected to gain growing importance across the country. However, solutions for effective pest and disease management remain limited. Many soil-borne phytopathogens that affect other crops can also infect chickpeas, increasing disease incidence due to higher initial inoculum levels. This study aimed to evaluate the effects of concentrated metabolites produced by Rhizobium tropici (CM-RT) on resistance induction and control of Sclerotinia sclerotiorum in chickpeas. Different CM-RT application methods were tested and disease incidence was assessed. Additionally, the relative expression of several defence-related genes was analyzed in CM-RT treated plants. Our results show that root application of CM-RT significantly reduced disease incidence and was statistically equivalent to the commercial elicitor based on acibenzolar-S-methyl. Gene expression analysis revealed the upregulation of key defence genes involved in jasmonic acid, ethylene, and oxidative stress pathways, suggesting a priming effect. These findings suggest that CM-RT can serve as an effective and eco-friendly alternative for disease control by resistance induction in chickpeas.

https://onlinelibrary.wiley.com/doi/10.1002/sae2.70103