<i>BdNub</i> Is Essential for Maintaining gut Immunity and Microbiome Homeostasis in <i>Bactrocera dorsalis</i>
Jian Gu,
Ping Zhang,
Zhichao Yao,
Xiaoxue Li,
Hongyu Zhang
Affiliations
Jian Gu
National Key Laboratory for Germplasm Innovation and Utilization for Fruit and Vegetable Horticultural Crops, Hubei Hongshan Laboratory, Institute of Urban and Horticultural Entomology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
Ping Zhang
National Key Laboratory for Germplasm Innovation and Utilization for Fruit and Vegetable Horticultural Crops, Hubei Hongshan Laboratory, Institute of Urban and Horticultural Entomology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
Zhichao Yao
National Key Laboratory for Germplasm Innovation and Utilization for Fruit and Vegetable Horticultural Crops, Hubei Hongshan Laboratory, Institute of Urban and Horticultural Entomology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
Xiaoxue Li
National Key Laboratory for Germplasm Innovation and Utilization for Fruit and Vegetable Horticultural Crops, Hubei Hongshan Laboratory, Institute of Urban and Horticultural Entomology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
Hongyu Zhang
National Key Laboratory for Germplasm Innovation and Utilization for Fruit and Vegetable Horticultural Crops, Hubei Hongshan Laboratory, Institute of Urban and Horticultural Entomology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
Insects face immune challenges posed by invading and indigenous bacteria. They rely on the immune system to clear these microorganisms. However, the immune response can be harmful to the host. Therefore, fine-tuning the immune response to maintain tissue homeostasis is of great importance to the survival of insects. The Nub gene of the OCT/POU family regulates the intestinal IMD pathway. However, the role of the Nub gene in regulating host microbiota remains unstudied. Here, a combination of bioinformatic tools, RNA interference, and qPCR methods were adopted to study BdNub gene function in Bactrocera dorsalis gut immune system. It’s found that BdNubX1, BdNubX2, and antimicrobial peptides (AMPs), including Diptcin (Dpt), Cecropin (Cec), AttcinA (Att A), AttcinB (Att B) and AttcinC (Att C) are significantly up-regulated in Tephritidae fruit fly Bactrocera dorsalis after gut infection. Silencing BdNubX1 leads to down-regulated AMPs expression, while BdNubX2 RNAi leads to increased expression of AMPs. These results indicate that BdNubX1 is a positive regulatory gene of the IMD pathway, while BdNubX2 negatively regulates IMD pathway activity. Further studies also revealed that BdNubX1 and BdNubX2 are associated with gut microbiota composition, possibly through regulation of IMD pathway activity. Our results prove that the Nub gene is evolutionarily conserved and participates in maintaining gut microbiota homeostasis.
