Arabidopsis thaliana Remorins Interact with SnRK1 and Play a Role in Susceptibility to Beet Curly Top Virus and Beet Severe Curly Top Virus

Abstract

Remorins, a family of plant-specific proteins containing a variable N-terminal region and conserved C-terminal domain, play a role in various biotic and abiotic stresses, including host-microbe interactions. However, their functions remain to be completely elucidated, especially for the Arabidopsis thaliana remorin group 4 (AtREM4). To elucidate the role of remorins in Arabidopsis, we first showed that AtREM4s have typical molecular characteristics of the remorins, such as induction by various types of biotic and abiotic stresses, localization in plasma membrane and homo- and hetero-oligomeric interaction. Next, we showed that their loss-of-function mutants displayed reduced susceptibility to geminiviruses, Beet Curly Top Virus and Beet Severe Curly Top Virus, while overexpressors enhanced susceptibility. Moreover, we found that they interacted with SnRK1, which phosphorylated AtREM4.1, and were degraded by the 26S proteasome pathway. These results suggest that AtREM4s may be involved in the SnRK1-mediated signaling pathway and play a role as positive regulators of the cell cycle during geminivirus infection.

The plant calcium-dependent protein kinase CPK3 phosphorylates REM1.3 to restrict viral infection

“…REM1.3's phospho-status defines its plasma membrane nanodomain organization and is crucial for REM1.3-dependent restriction of PVX cell-to-cell movement by regulation of callose deposition at plasmodesmata. This study unveils plasma membrane nanodomain-associated molecular events underlying the plant immune response to viruses.reports of different REM phospho-statuses suggest that the activity of these proteins could be regulated by phosphorylation during plant-microbe interactions 14,15,34,35 .In the present paper, we show that phosphorylation of REM dictates its membrane dynamic and antiviral defense by the reduction of PD permeability. Our data points toward a model whereby viral proteins such as the Coat Protein (CP), TGBp1 from PVX and 30K proteins from Tobacco mosaic virus (TMV) elicit the activation of protein kinase(s), which in turn phosphorylate(s) REM1.3 at its Nterminal domain.…”

“…Since various studies have reported REM phosphorylation during plant-microbe interactions 14 15 34 35 , we set out to address which kinase phosphorylates REM and whether REM1.3 phosphorylation plays a role in REM-mediated anti-viral defense. Indeed, our experimental findings show that plant PVX sensing induces the activation of a membrane-bound calcium-dependent protein kinase that in turn phosphorylates REM1.3 (Fig 2, Fig EV2, Fig 5).…”

“…The REM C-terminal domain, contain a predicted coiled-coil (residues 117-152) which is thought to regulate REM oligomerization 10,13,14 and may be involved in regulating REM spatial organization at the PM. Members of the REM family have been associated with plant responses to biotic 8,15,16 , abiotic stress 17 18 and developmental clues 11 and current view suggest they could regulate signaling events through nanodomain association. However, the molecular mechanisms leading to REM downstream events remain elusive.…”

“…reports of different REM phospho-statuses suggest that the activity of these proteins could be regulated by phosphorylation during plant-microbe interactions 14,15,34,35 .…”

A remorin from Nicotiana benthamiana interacts with the Pseudomonas type-III effector protein HopZ1a and is phosphorylated by the immune-related kinase PBS1

“…Remorins from different plant species have been associated with plant defense responses (Jarsch and Ott, 2011; Bozkurt et al, 2014; Son et al, 2014; Fu et al, 2018). Given the fact that the majority of Pseudomonas T3Es target immunity related functions inside the host cell (Büttner, 2016; Khan et al, 2018a), the interaction of NbREM4 with HopZ1a points towards an involvement of NbREM4 in some sort of plant defense response.…”