Abstract
Potato cyst nematodes (PCNs), including
Globodera rostochiensis
(Woll.), are important pests of potato. Plant parasitic nematodes produce multiple effector proteins, secreted from their stylets, to successfully infect their hosts. These include proteins delivered to the apoplast and to the host cytoplasm. A number of effectors from
G. rostochiensis
predicted to be delivered to the host cytoplasm have been identified, including several belonging to the secreted SPRY domain (SPRYSEC) family. SPRYSEC proteins are unique to members of the genus
Globodera
and have been implicated in both the induction and the repression of host defense responses. We have tested the properties of six different
G. rostochiensis
SPRYSEC proteins by expressing them in
Nicotiana benthamiana
and
N. tabacum
. We have found that all SPRYSEC proteins tested are able to suppress defense responses induced by NB-LRR proteins as well as cell death induced by elicitors, suggesting that defense repression is a common characteristic of members of this effector protein family. At the same time,
Gr
SPRYSEC-15 elicited a defense responses in
N. tabacum
, which was found to be resistant to a virus expressing
Gr
SPRYSEC-15. These results suggest that SPRYSEC proteins may possess characteristics that allow them to be recognized by the plant immune system.