Gut bacteria promotes host fitness to special ecological niche by regulating sugar metabolism in Drosophila suzukii

Abstract

As an important fruit pest of global significance, Drosophila suzukii (Matsumura, 1931) has the special ecological niche with high sugar and low protein, which is different from other Drosophila species in fruits. Gut bacteria have a substantial impact on insect physiology and ecology. However, the contribution of gut microbes to host fitness to special ecological niche is still unclear. This study examined the role of K. oxytoca in development of D. suzukii at physiological and molecular levels. The results showed that, after being removed gut microbiota, the survival rate and the longevity was significantly decreased in D. suzukii (NB strain), while the recolonization of K. oxytoca mainly in D. suzukii midgut (KO strain) helped NB strain promote the development level. The differentially expressed genes and metabolites between NB strain and KO strain could be enriched in carbohydrate metabolism pathways. qPCR analysis and sugar inducing experiment confirmed that, K. oxytoca could promote the development and sugar metabolism of D. suzukii through increasing glycolysis rate and regulating the transcript level of genes HK, PK, PFK, G6Pc, PEPCK in glycolysis/gluconeogenesis pathway. It was suggested that K. oxytoca plays an important role in promoting the host fitness to high-sugar ecological niche by stimulating its glycolysis/gluconeogenesis pathway. Our result may provide a new target for controlling D. suzukii, that is, to inhibit sugar metabolism in D. suzukii by disturbing the regulated role of K. oxytoca and the balance of gut microbial communities.