Role of Gut Bacteria in Enhancing Host Adaptation of Tuta absoluta to Different Host Plants.

The insect gut bacteria play important roles in insect development and growth, such as immune defense, nutrient metabolism, regulating insect adaptations for plants, etc. The Tuta absoluta (Meyrick) is a destructive invasive pest that mainly feeds on solanaceae plants. However, the relationship between gut microflora and host adaption of T. absoluta remains to be known. In this study, we first compared the survival adaptability of T. absoluta feeding with two host plants (tomatoes and potatoes). The T. absoluta completed the generation cycle by feeding on the leaves of both plants. However, the larvae feeding on tomato leaves have shorter larvae durations, longer adult durations, and a greater number of egg production per female. After Single Molecular Real-Time (SMRT) sequencing, according to the LDA Effect Size (LEfSe) analysis, the gut bacterial biomarker of T. absoluta fed on tomato was Enterobacter cloacae and the gut bacterial biomarker of T. absoluta fed on potatoes was Staphylococcus gallinarum and Enterococcus gallinarum. Furthermore, a total of 6 and 7 culturable bacteria were isolated from the guts of tomato- and potato-treated T. absoluta, respectively. However, the isolated strains included bacterial biomarkers E. cloacae and S. gallinarum but not E. gallinarum. In addition, different stains bacterial biomarkers on T. absoluta feeding selection were also studied. E. cloacae enhanced the host preference of the SLTA (T. absoluta of tomato strain) for tomato but had no impact on STTA (T. absoluta of potato strain). S. gallinarum improved the host preference of STTA to a potato but did not affect SLTA. The results showed that the gut bacteria of T. absoluta were affected by exposure to different host plants, and the bacterial biomarkers played an important role in host adaptability. This study not only deepens our understanding of gut bacteria-mediated insect-plant interactions but also provides theoretical support for the development of environmentally friendly and effective agricultural pest control methods.