Molecular Plant-Microbe Interactions (2016) 29, 750-766

Omar Arias Gaguancela, Lizbeth Peña Zúñiga, Alexis Vela Arias, Dennis Halterman, Francisco Javier Flores, Ida Elisabeth Johansen, Aiming Wang, Yasuyuki Yamaji and Jeanmarie Verchot (2016)
The IRE1/bZIP60 pathway and Bax inhibitor 1 suppress systemic accumulation of potyviruses and potexviruses in Arabidopsis and Nicotiana benthamiana plants
Molecular Plant-Microbe Interactions 29 (10), 750-766
Abstract: The inositol requiring enzyme (IRE1) is an endoplasmic reticulum (ER) stress sensor. When activated, it splices the bZIP60 mRNA, producing a truncated transcription factor that upregulates genes involved in the unfolded protein response. Bax inhibitor 1 (BI-1) is another ER stress sensor that regulates cell death in response to environmental assaults. The potyvirus 6K2 and potexvirus TGB3 proteins are known to reside in the ER, serving, respectively, as anchors for the viral replicase and movement protein complex. This study used green fluorescent protein (GFP)-tagged Turnip mosaic virus (TuMV), Plantago asiatica mosaic virus (PlAMV), Potato virus Y (PVY), and Potato virus X (PVX) to determine that the IRE1/bZIP60 pathway and BI-1 machinery are induced early in virus infection in Arabidopsis thaliana, Nicotiana benthamiana, and Solanum tuberosum. Agrodelivery of only the potyvirus 6K2 or TGB3 genes into plant cells activated bZIP60 and BI-1 expression in Arabidopsis thaliana, N. benthamiana, and S. tuberosum. Homozygous ire1a-2, ire1b-4, and ire1a-2/ire1b-4 mutant Arabidopsis plants were inoculated with TuMV-GFP or PlAMV-GFP. PlAMV accumulates to a higher level in ire1a-2 or ire1a-2/ire1b-4 mutant plants than in ire1b-4 or wild-type plants. TuMV-GFP accumulates to a higher level in ire1a-2, ire1b-4, or ire1a-2/ire1b-4 compared with wild-type plants, suggesting that both isoforms contribute to TuMV-GFP infection. Gene silencing was used to knock down bZIP60 and BI-1 expression in N. benthamiana. PVX-GFP and PVY-GFP accumulation was significantly elevated in these silenced plants compared with control plants. This study demonstrates that two ER stress pathways, namely IRE1/bZIP60 and the BI-1 pathway, limit systemic accumulation of potyvirus and potexvirus infection. Silencing BI-1 expression also resulted in systemic necrosis. These data suggest that ER stress–activated pathways, led by IRE1 and BI-1, respond to invading potyvirus and potexviruses to restrict virus infection and enable physiological changes enabling plants to tolerate virus assault.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Ai Ming Wang, Dennis Halterman, Ida Elisabeth Johansen

Research topic(s) for pests/diseases/weeds:
resistance/tolerance/defence of host

---

Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Potato virus Y
	Potato virus X
	Turnip mosaic virus
	Plantago asiatica mosaic virus