The Influence of Temperature and Host Gender on Bacterial Communities in the Asian Citrus Psyllid

SIMPLE SUMMARY: Diaphorina citri is an important natural vector for the Huanglongbing pathogen, which causes destructive damage to citrus production. The temperature and gender are critical abiotic and biotic factors affecting insect physiology as well as the symbiont abundance. Nevertheless, how temperature and gender affect the bacterial communities present in D. citri is still unclear. This study used high-throughput sequencing of 16S ribosomal RNA amplicons to identify amplicon sequence variants in D. citri. The dominant phylum was Proteobacteria, and Candidatus Profftella and Wolbachia were the dominant taxa in all groups. Furthermore, under a high-temperature treatment, Profftella was the prevalent symbiont in females, but Wolbachia had a higher abundance in males. In males, Profftella was more abundant under low-temperature treatments than high-temperature treatments. In contrast, Wolbachia showed a higher abundance under high-temperature treatments than under low-temperature treatments. The results will provide a new vision for understanding the co-adaptation of D. citri and its symbionts to environmental stresses. ABSTRACT: The Asian citrus psyllid, D. citri Kuwayama is the primary vector for Candidatus Liberibacter asiaticus (CLas), which causes a destructive disease in citrus plants. Bacterial symbionts are important determinants of insect physiology, and they can be impacted by many external factors. Temperature is an important abiotic factor affecting insect physiology, and it is also known that differences in symbiont proportions may vary in different insect genders. To date, it is unclear how the symbionts of D. citri are affected by temperature and gender. This study used high-throughput sequencing of 16S ribosomal RNA amplicons to determine how temperature and gender affect the bacterial communities present in D. citri. We identified 27 amplicon sequence variants (ASVs) belonging to 10 orders, seven classes, and five phyla. The dominant phylum was Proteobacteria (99.93%). Other phyla, including Firmicutes, Bacteroidota, Deinococcota, Cyanobacteria, and Actinobacteriota, were less abundant (<0.1%). Profftella (71.77–81.59%) and Wolbachia (18.39–28.22%) were the predominant taxa in all samples. Under high-temperature treatment, Profftella was more common in females, while Wolbachia had a higher abundance in males. In males, Profftella was more abundant under low-temperature treatments than under high-temperature treatments. In contrast, Wolbachia showed a higher abundance under high-temperature treatments than under low-temperature treatments. An RT-qPCR (quantitative real-time PCR) approach confirmed the results obtained with high-throughput DNA sequencing. Our results provide a basis for understanding the co-adaptation of D. citri and its symbionts to environmental temperature stress.