AUTHOR=Zhang Yue , Yang Jiapeng , Dai Renhuai , Yang Wenjia , Zhang Xiaomin 

TITLE=Immune function analysis of LsSd, a transcription factor of the Hippo signaling pathway, in the cigarette beetle Lasioderma serricorne

JOURNAL=Frontiers in Physiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2022.1042897

DOI=10.3389/fphys.2022.1042897

ISSN=1664-042X

ABSTRACT=<p>The Scalloped (Sd) is a transcription factor that regulates organ size control in the Hippo-signaling pathway. Recent studies have showed that Hippo signaling also functions in the innate immune response. Although the Sd gene has been reported in many insects, their immune functions remain unexplored. In this study, the <italic>LsSd</italic> gene of <italic>Lasioderma serricorne</italic>, with a complete open reading frame that encodes a protein composed of 402 amino acids was identified. <italic>LsSd</italic> was predominantly expressed in early pupae. Tissue-specific analyses revealed that the highest concentrations of <italic>LsSd</italic> were detected in the midgut and brain. At 1–24 h after <italic>Escherichia coli</italic> infection, <italic>LsSd</italic> expression increased substantially. However, <italic>LsSd</italic> expression was downregulated 3–12 h after <italic>Staphylococcus aureus</italic> infection. RNA interference-mediated silencing of the <italic>LsSd</italic> transcript resulted in deformed, considerably smaller, and degenerated wings. Meanwhile, <italic>LsCycE</italic>, <italic>LsDiap1</italic>, and <italic>LsVg</italic>, which are involved in cell proliferation and wing development, were drastically reduced when <italic>LsSd</italic> was depleted. In a survival assay, the <italic>LsSd</italic> knockdown considerably decreased the susceptibility to <italic>S. aureus</italic>, a gram-positive bacterium. In addition, knockdown of <italic>LsSd</italic> remarkably downregulated the transcription of <italic>LsCact</italic> in response to <italic>S. aureus</italic> stimulation, while upregulating the expression of five immune-related genes. Our results provide conclusive proof for the important roles of <italic>LsSd</italic> in the immune response of <italic>L. serricorne</italic>.</p>