The potato Rx1 is an intracellular Nucleotide-binding Leucine Rich Repeat (NLR) immune receptor with an archetypical N-terminal coiled-coil (CC) domain. It confers extreme resistance against Potato Virus X (PVX) by gene-specific recognition of the viral coat protein (CP). Recent findings point to a role of Rx1 in the nucleus whereby it could directly bind host genetic material, though it remains unclear how this process eventually leads to defence. A possibility is that Rx1 recruits other host factors, for example via the CC domain, which is predicted to act as scaffolds for nuclear signalling. Here, we used the CC domains of Rx1 and the Rx1-like protein Gpa2 (mediates defence against the nematode Globodera pallida) as baits in a Co-IP/MS analysis after cell fractionation to co-purify putative interactors from Nicotiana benthamiana. Five hits (designated Rp01-Rp05) were further prioritized as candidate Rx1/Gpa2 interacting proteins. Similar pull-down experiments confirmed complex formation with the full-length immune receptors in plantae. Interestingly, co-expression of Rp05 alters the subcellular distribution of the Rx1-CC domain, hinting its role in Rx1-function. Transient overexpression experiments confirm that Rp05 could in fact potentiate defense against PVX. Interestingly, however, this occurs independently of Rx1. We substantiated this model by demonstrating that Rp05 could influence HR-responses by other NLR proteins (e.g. Gpa2, Sw5A/B and Mi-1) indicating that it may be a common downstream component in immune signaling. Currently, we focus on elucidating the detailed molecular underpinning of Rp05 function in R-gene mediated resistances using Rx1 as the principal model system.
|Publication status||Published - 1 Mar 2017|
|Event||4th Annual Conference of the COST Action - Bled, Slovenia|
Duration: 1 Mar 2017 → 3 Mar 2017
|Conference||4th Annual Conference of the COST Action|
|Period||1/03/17 → 3/03/17|