Variable membrane protein A of flavescence dorée phytoplasma binds the midgut perimicrovillar membrane of Euscelidius variegatus and promotes adhesion to its epithelial cells
Articolo
Data di Pubblicazione:
2018
Abstract:
Phytoplasmas are uncultivated plant pathogens and cell wall-less bacteria
and are transmitted from plant to plant by hemipteran insects. The phytoplasma’s
circulative propagative cycle in insects requires the crossing of the midgut and
salivary glands, and primary adhesion to cells is an initial step toward the invasion
process. The flavescence dorée (FD) phytoplasma possesses a set of variable membrane
proteins (Vmps) exposed on its surface, and this pathogen is suspected to interact
with insect cells. The results showed that VmpA is expressed by the flavescence
dorée phytoplasma present in the midgut and salivary glands. Phytoplasmas
cannot be cultivated at present, and no mutant can be produced to investigate the
putative role of Vmps in the adhesion of phytoplasma to insect cells. To overcome
this difficulty, we engineered the Spiroplasma citri mutant G/6, which lacks the
ScARP adhesins, for VmpA expression and used VmpA-coated fluorescent beads to
determine if VmpA acts as an adhesin in ex vivo adhesion assays and in vivo ingestion
assays. VmpA specifically interacted with Euscelidius variegatus insect cells in
culture and promoted the retention of VmpA-coated beads to the midgut of E. variegatus.
In this latest case, VmpA-coated fluorescent beads were localized and embedded
in the perimicrovillar membrane of the insect midgut. Thus, VmpA functions
as an adhesin that could be essential in the colonization of the insect by the FD
phytoplasmas.
Tipologia CRIS:
03A-Articolo su Rivista
Keywords:
phytoplasma, spiroplasma, bacterial adhesion to cell, insect vector, transmission
Elenco autori:
Arricau-Bouvery, N., Duret, S., Dubrana, M. P., Batailler, B., Desqué, D., Béven, L., Danet J.L., Monticone M., Bosco, D, Malembic-Maher S. and Foissac, X.
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