Transcriptomic Analysis Reveals Molecular Mechanisms of Wolbachia–Plant Association

Endosymbiotic bacteria in insects are known to influence plant–insect interactions by altering host plant physiology. This study reveals that the endosymbiont Wolbachia significantly impairs photosynthesis in cotton plants. Comparative transcriptomic analysis of cotton leaves infested by Wolbachia-infected spider mites (Tt-I) and uninfected spider mites (Tt-UI) identified 1912 differentially expressed genes (DEGs). Photosynthesis was the most adversely affected biological process, with 17 genes downregulated in the photosynthesis pathway (e.g., key genes psbW and PETF), as supported by GO and KEGG enrichment analyses. Gene co-expression network analysis further highlighted core genes involved in photosynthesis disruption and carbon fixation. Physiological assessments showed that Wolbachia infection led to significantly reduced chlorophyll content and elevated reactive oxygen species (ROS) levels, inducing oxidative stress. These findings demonstrate that Wolbachia disrupts cotton photosynthesis through transcriptional repression and ROS-mediated oxidative stress, providing novel insights into plant–insect-symbiont interactions and a theoretical basis for managing mite pests in cotton.