Infection Function of Adhesin-Like Protein ALP609 from Spiroplasma melliferum CH-1

Abstract

Spiroplasma melliferum is the causative agent of spiroplasmosis in honeybees. During infection, adhesion of spiroplasmas to the host cells through adhesion factors is a crucial step. In this study, we identified an adhesin-like protein (ALP609) in S. melliferum CH-1 and investigated its role in the infection. To determine whether ALP609 is an adhesion factor, we performed indirect immunofluorescence microscopy to visualize its adhesion properties. Subsequently, an infection model of S. melliferum CH-1 was established using primary midgut cells of Apis mellifera to examine the adhesion and invasion of spiroplasma using anti-ALP609 antibodies inhibition assays and competition assays with recombinant ALP609 in vitro. We found that anti-ALP609 antibodies could inhibit the adhesion and invasion of spiroplasma to the midgut cells of A. mellifera and reduce midgut cell invasion on increased exposure to recombinant ALP609. To the best of our knowledge, this is the first report identifying adhesion-related factors in S. melliferum. Our results suggested that ALP609 is an adhesin-like protein critical for invasion of S. melliferum CH-1 into midgut cells of A. mellifera.

Blind killing of both male and female Drosophila embryos by a natural variant of the endosymbiotic bacterium Spiroplasma poulsonii

“…RNAseq analysis showed that virulence factors were either not differentially expressed or downregulated in BK, with the exception of adhesin coding genes. Adhesin‐like proteins have been shown to be necessary for pathogenic Spiroplasma species to adhere to and invade host cells (Béven et al, ; Breton et al, ; Hou et al, ; Zha, Yang, Wang, Yang, & Yu, ), these could thus be responsible for the BK strain increased pathogenicity. Future studies are required to address the role of these proteins in endosymbiotic Spiroplasma and determine whether they are involved in the BK phenotype.…”