Symbiont Diversity of Rice-Associated Leafhoppers (Cicadellidae) in the Tropical Floodplains of the Tonle Sap Lake, Cambodia

Rice-associated leafhoppers (Cicadellidae) play a significant role in rice agroecosystems, contributing not only to direct crop damage but also to the transmission of plant pathogens. This study investigates the symbiont diversity of seventeen leafhopper species from the tropical floodplains of Tonle Sap Lake (TSL), Cambodia. The dominant symbiont across most species was Candidatus (Ca.) Karelsulcia muelleri, an obligate primary endosymbiont essential for nutrient synthesis. The co-obligate symbiont Ca. Nasuia deltocephalinicola was also consistently detected, particularly in Deltocephalinae hosts. In addition, several secondary symbionts, including Sodalis, Arsenophonus, Diplorickettsia, Rickettsia, Wolbachia, and Ca. Lariskella, were identified, showing species-specific associations and potential roles in host fitness and pathogen transmission. Variations in symbiont diversity were observed across cicadellid species, geographic origins, and between sex-associated symbionts, with notable differences in the bacterial composition of Nephotettix virescens. While geographical differences (Battambang vs. Kampong Thom) did not strongly affect microbial composition, sex-associated variations were evident in N. virescens. Females exhibited a higher abundance of Karelsulcia and Nasuia, suggesting possible microbial adaptation related to reproduction. This study highlights the complex and dynamic nature of cicadellid hosts-symbiont interactions and suggests that microbial communities are primarily structured by host species. While geographic distance can influence these communities, this effect is not the same for every species. These findings provide critical insights into the microbial diversity of rice-associated leafhoppers and their potential for ecological roles in rice farming systems. Further studies, including functional analysis and host-symbiont interactions, are crucial to understanding the ecological roles and evolutionary dynamics of these microbial communities.