Rishi Bhandari, Potnis Lab, Department of Entomology and Plant Pathology, Auburn University, Auburn, USA
Host-associated microbial communities play a crucial role in protecting hosts from various stresses. However, our understanding of how changing environmental conditions influence plant-pathogen interactions and the contributions of plant-associated microbial communities to resilience against biotic and abiotic stresses remains limited. To address this knowledge gap, we conducted a study using temporal metagenomics to examine the effects of elevated ozone levels on pepper cultivars that were either resistant or susceptible to Xanthomonas. Although overall host susceptibility was unaffected by ozone, it increased the disease severity in the resistant cultivar, potentially compromising its resistance. Pathogen challenge led to distinct microbial community structures in both cultivars. Furthermore, elevated ozone influenced the microbial community structure of the resistant cultivar while leaving the susceptible cultivar unaffected, thus highlighting the role of the host genotypic background in responding to abiotic stress. Under combined stress, the microbial composition exhibited a similar shift as observed with the pathogen challenge alone, indicating a prioritization of response to the most significant stress factor. Notably, despite compositional differences, the phyllosphere community displayed functional redundancy. Network analysis revealed a stable network with increased connectivity during pathogen challenge, suggesting robust community-level interactions. However, the combined stress disrupted the network and altered hub taxa. This study highlights the importance of understanding host-microbe interactions in managing host susceptibility under changing climate, providing valuable insights into the intricate dynamics between the microbiome, stressors, and host resistance.