Type I J-Domain NbMIP1 Proteins Are Required for Both Tobacco Mosaic Virus Infection and Plant Innate Immunity

Abstract

Tm-22 is a coiled coil-nucleotide binding-leucine rich repeat resistance protein that confers durable extreme resistance against Tomato mosaic virus (ToMV) and Tobacco mosaic virus (TMV) by recognizing the viral movement protein (MP). Here we report that the Nicotiana benthamiana J-domain MIP1 proteins (NbMIP1s) associate with tobamovirus MP, Tm-22 and SGT1. Silencing of NbMIP1s reduced TMV movement and compromised Tm-22-mediated resistance against TMV and ToMV. Furthermore, silencing of NbMIP1s reduced the steady-state protein levels of ToMV MP and Tm-22. Moreover, NbMIP1s are required for plant resistance induced by other R genes and the nonhost pathogen Pseudomonas syringae pv. tomato (Pst) DC3000. In addition, we found that SGT1 associates with Tm-22 and is required for Tm-22-mediated resistance against TMV. These results suggest that NbMIP1s function as co-chaperones during virus infection and plant immunity.

Antiviral Resistance Protein Tm-22 Functions on the Plasma Membrane

“…In this study, we consistently observed accumulation of Tm-2 2 -YFP-HA in PM, but not in the interspersed spots as reported previously for Tm-2 2 -YFP (Du et al, 2013). However, a through confocal microscopy assay indicated that Tm-2 2 -YFP also accumulated in PM in addition to some interspersed dots along with cell membranes (Supplemental Fig.…”

“…This discrepancy may be caused by the protein level, time after infiltration, extra tag sequence, or some other unknown technical differences. Nonetheless, both Tm-2 2 -YFP-HA and Tm-2 2 -YFP are sufficient to confer TMV resistance and induce HR in the presence of MP (this study; Du et al, 2013). These data suggest that the accumulation in PM, but not in the interspersed dots, is responsible for Tm-2 2 function.…”

“…the viral movement protein (MP; Meshi et al, 1989;Weber and Pfitzner, 1998), and its LRR domain is involved in this recognition (Lanfermeijer et al, 2005;Kobayashi et al, 2011). Rubisco small subunit and Type I J-Domain NbMIP1 proteins are involved in Tm-2 2 -mediated extreme resistance and viral movement (Du et al, 2013;Zhao et al, 2013).…”

Resistance-Gene-Mediated Defense Responses against Biotic Stresses in the Crop Model Plant Tomato

“…In addition, by utilizing transgenic tomato plants expressing NahG (encodes for an enzyme that metabolizes SA) a role for SA in Mi-1-mediated resistance to potato aphids was identified [141]. In a VIGS screen performed in N. benthamiana to identify the components of Mi-signaling that can suppress HR triggered by a constitutively active form of Mi-1, Mi-DS4, SERK1 was identified as an important player [142,143].…”

“…In addition, by utilizing transgenic tomato plants expressing NahG (encodes for an enzyme that metabolizes SA) a role for SA in Mi-1-mediated resistance to potato aphids was identified [141]. In a VIGS screen performed in N. benthamiana to identify the components of Mi-signaling that can suppress HR triggered by a constitutively active form of Mi-1, Mi-DS4, SERK1 was identified as an important player [142,143].To identify the tomato proteins that interact with ToMV movement protein or Tm-22-LRR yeast two-hybrid screens were performed and tomato cDNA library was screened, by using ToMV movement protein and Tm-22-LRR as respective baits [144]. In these screens Rubisco small subunit (RbCS) was identified as interacting with ToMV movement protein and SGT1 as interacting with Tm-22, in addition MP-Interacting Protein 1 (MIP1), a group of type I J-domain proteins was found to interact with both ToMV movement protein and Tm-22.…”