Gut bacterium promotes host fitness in special ecological niche by affecting sugar metabolism in Drosophila suzukii

• Published in: Insect science 2023-12, Vol.30 (6), p.1713-1733
• Main Authors: Gao, Huan‐Huan, Zhao, Shan, Wang, Rui‐Juan, Qin, Dong‐Yun, Chen, Peng, Zhang, An‐Sheng, Zhuang, Qian‐Ying, Zhai, Yi‐Fan, Zhou, Xian‐Hong
• Format: Article
• Language: English
• Subjects: Bacteria; Carbohydrate metabolism; Carbohydrates; Drosophila suzukii; Ecological effects; Ecological niches; Fitness; Fruit flies; Fruits; Genes; Germfree; Gluconeogenesis; Glycolysis; glycolysis/gluconeogenesis; Impact damage; Insect ecology; Insects; Intestinal microflora; Klebsiella; Klebsiella oxytoca; Metabolism; Metabolites; Microbial activity; Microbiota; Microorganisms; Midgut; Niches; Physiology; Proteins; Reintroduction; Sugar; Survival; symbiotic bacteria
• ISSN: 1672-9609; 1744-7917
• DOI: 10.1111/1744-7917.13189

As an important fruit pest of global significance, Drosophila suzukii occupies a special ecological niche, with the characteristics of high sugar and low protein contents. This niche differs from those occupied by other fruit‐damaging Drosophila species. Gut bacteria substantially impact the physiology and ecology of insects. However, the contribution of gut microbes to the fitness of D. suzukii in their special ecological niche remains unclear. In this study, the effect of Klebsiella oxytoca on the development of D. suzukii was examined at physiological and molecular levels. The results showed that, after the removal of gut microbiota, the survival rate and longevity of axenic D. suzukii decreased significantly. Reintroduction of K. oxytoca to the midgut of D. suzukii advanced the development level of D. suzukii. The differentially expressed genes and metabolites between axenic and K. oxytoca‐reintroduced D. suzukii were enriched in the pathways of carbohydrate metabolism. This advancement was achieved through an increased glycolysis rate and the regulation of the transcript level of key genes in the glycolysis/gluconeogenesis pathway. Klebsiella oxytoca is likely to play an important role in increasing host fitness in their high‐sugar ecological niche by stimulating the glycolysis/gluconeogenesis pathway. As a protein source, bacteria can also provide direct nutrition for D. suzukii, which depends on the quantity or biomass of K. oxytoca. This result may provide a new target for controlling D. suzukii by inhibiting sugar metabolism through eliminating the effect of K. oxytoca and thus disrupting the balance of gut microbial communities. Klebsiella oxytoca plays an important role in the development and sugar metabolism of Drosophila suzukii, and can be found abundantly in the midgut of D. suzukii. We have provided strong support for host fitness in a high‐sugar ecological niche by stimulating its glycolysis/gluconeogenesis pathway via the symbiosis gut bacteria K. oxytoca.