title: The PLA2 gene mediates the humoral immune responses in Bactrocera dorsalis (Hendel).
abstract: The phospholipase A2 (PLA2) gene encodes the enzyme that catalyzes the hydrolysis of phospholipids (PLs) from the sn-2 position. However, little is known about its role in humoral immune responses. In this study, we investigated the expression profile of PLA2 in different tissues and developmental stages in Bactrocera dorsalis (Hendel), and the results showed that the transcriptional level of PLA2 was high in the egg and mature stage and in the testis tissue. Bacterial infection increased the expression of PLA2, and the highest degree of up-regulation appeared in the fat body. Silencing PLA2 influenced the expression of immune-related genes, including MyD88 and defensin in the Toll pathway and relish and diptericin in the Imd pathway. Moreover, the expression of MyD88 and defensin was down-regulated significantly in the ds-PLA2 group compared with those in the ds-egfp group when B. dorsalis was infected with L. monocytogenes and S. aureus, indicating that PLA2 was involved in the activation of the Toll pathway. Meanwhile, infection with L. monocytogenes and E. coli, which activate the Imd pathway, does not increase the mRNA levels of relish and diptericin in the ds-PLA2 group as severely as it increases those in the ds-egfp group, indicating that the Imd pathway was also repressed after silencing PLA2. Notably, the development of lipid droplets in fat body cells was influenced by silencing PLA2, implying that PLA2 affects the function of fat body tissue. These results suggest that the PLA2 gene may mediate humoral immune responses by reducing lipid storage in fat body cells in B. dorsalis.
authors.affiliation: Key Laboratory of Horticultural Plant Biology (MOE), State Key Laboratory of Agricultural Microbiology, Institute of Urban and Horticultural Entomology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Qiujia
authors.initials: Q
authors.lastname: Li
authors.affiliation: Key Laboratory of Horticultural Plant Biology (MOE), State Key Laboratory of Agricultural Microbiology, Institute of Urban and Horticultural Entomology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Xiaolong
authors.initials: X
authors.lastname: Dong
authors.affiliation: Key Laboratory of Horticultural Plant Biology (MOE), State Key Laboratory of Agricultural Microbiology, Institute of Urban and Horticultural Entomology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Zheng
authors.affiliation: Key Laboratory of Horticultural Plant Biology (MOE), State Key Laboratory of Agricultural Microbiology, Institute of Urban and Horticultural Entomology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China. Electronic address: hongyu.zhang@mail.hzau.edu.cn.
authors.forename: Hongyu
authors.initials: H
authors.lastname: Zhang
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D023082:Defensins / Q000235:genetics / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics; D005216:Fat Body / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D056724:Immunity, Humoral; D050356:Lipid Metabolism; D008088:Listeriosis / Q000276:immunology*; D008297:Male; D053594:Myeloid Differentiation Factor 88 / Q000235:genetics / Q000378:metabolism; D054467:Phospholipases A2 / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics; D013203:Staphylococcal Infections / Q000276:immunology*; D013211:Staphylococcus aureus / Q000276:immunology*; D033621:Tephritidae / Q000276:immunology*; D013737:Testis / Q000378:metabolism*; D051193:Toll-Like Receptors / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics; D059467:Transcriptome
chemical_list: D023082:Defensins; C054756:DptA protein, Drosophila; D029721:Drosophila Proteins; D053594:Myeloid Differentiation Factor 88; D034741:RNA, Small Interfering; C101626:Rel protein, Drosophila; D051193:Toll-Like Receptors; D014157:Transcription Factors; D054467:Phospholipases A2
keywords: Bactrocera dorsalis; Humoral immune response; Immune deficiency pathway; PLA2 gene; Toll pathway