Abstract
The production of influenza vaccines in plants is achieved through transient expression of viral hemagglutinins (HAs), a process mediated by the bacterial vector Agrobacterium tumefaciens. HA proteins are then produced and matured through the secretory pathway of plant cells, before being trafficked to the plasma membrane where they induce formation of virus-like particles (VLPs). Production of VLPs unavoidably impacts plant cells, as do viral suppressors of RNA silencing (VSRs) that are co-expressed to increase recombinant protein yields. However, little information is available on host molecular responses to foreign protein expression. This work provides a comprehensive overview of molecular changes occurring in Nicotiana benthamiana leaf cells transiently expressing the VSR P19, or co-expressing P19 and an influenza HA. Our data identifies general responses to Agrobacterium-mediated expression of foreign proteins, including shutdown of chloroplast gene expression, activation of oxidative stress responses and reinforcement of the plant cell wall through lignification. Our results also indicate that P19 expression promotes salicylic acid (SA) signalling, a process dampened by co-expression of the HA protein. While reducing P19 level, HA expression also induces specific signatures, with effects on lipid metabolism, lipid distribution within membranes and oxylipin-related signalling. When producing VLPs, dampening of P19 responses thus likely results from lower expression of the VSR, crosstalk between SA and oxylipin pathways, or a combination of both outcomes. Consistent with the upregulation of oxidative stress responses, we finally show that reduction of oxidative stress damage through exogenous application of ascorbic acid improves plant biomass quality during production of VLPs.
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Claims 8
Claim · model-written summary
Agrobacterium-mediated foreign protein expression shut down chloroplast gene expression.
- Taxon
- Nicotiana benthamiana
Nicotiana benthamianat0 - Treatment
- Agrobacterium-mediated expression of foreign proteinse0
- Outcome
- chloroplast gene expressione0
- Direction
- shutdowne0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“responses to Agrobacterium-mediated expression of foreign proteins, including shutdown of chloroplast gene expression”
t0“Nicotiana benthamiana”
Claim · model-written summary
Foreign protein expression activated oxidative stress responses and cell wall lignification.
- Taxon
- Nicotiana benthamianaNicotiana benthamianat0
- Treatment
- Agrobacterium-mediated expression of foreign proteinse0
- Outcome
- oxidative stress responses and reinforcement of the plant cell wall through lignificatione0
- Direction
- activatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Agrobacterium-mediated expression of foreign proteins, including shutdown of chloroplast gene expression, activation of oxidative stress responses and reinforcement of the plant cell wall through lignification”
t0“Nicotiana benthamiana”
Claim · model-written summary
P19 expression promoted salicylic acid signalling.
- Taxon
- Nicotiana benthamianaNicotiana benthamianat0
- Treatment
- P19 expressione0
- Gene
- P19e0
- Outcome
- salicylic acid (SA) signallinge0
- Direction
- promotese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“P19 expression promotes salicylic acid (SA) signalling”
t0“Nicotiana benthamiana”
Claim · model-written summary
HA co-expression dampened P19-associated salicylic acid signalling.
- Taxon
- Nicotiana benthamianaNicotiana benthamianat0
- Treatment
- co-expression of the HA proteine0
- Outcome
- salicylic acid (SA) signallinge1
- Direction
- dampenede0
- Comparator
- P19 expressione1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a process dampened by co-expression of the HA protein”
e1“P19 expression promotes salicylic acid (SA) signalling”
t0“Nicotiana benthamiana”
Claim · model-written summary
HA expression reduced P19 level.
- Taxon
- Nicotiana benthamianaNicotiana benthamianat0
- Treatment
- HA expressione0
- Outcome
- P19 levele0
- Direction
- reducinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“reducing P19 level, HA expression also induces specific signatures”
t0“Nicotiana benthamiana”
Claim · model-written summary
HA expression affected lipid metabolism, membrane lipid distribution and oxylipin signalling.
- Taxon
- Nicotiana benthamianaNicotiana benthamianat0
- Treatment
- HA expressione0
- Outcome
- lipid metabolism, lipid distribution within membranes and oxylipin-related signallinge0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“HA expression also induces specific signatures, with effects on lipid metabolism, lipid distribution within membranes and oxylipin-related signalling”
t0“Nicotiana benthamiana”
Claim · model-written summary
Lower P19 expression or salicylic acid–oxylipin crosstalk may explain dampened P19 responses during VLP production.
- Taxon
- Nicotiana benthamianaNicotiana benthamianat0
- Outcome
- dampening of P19 responsese0
- Qualifier
- lower expression of the VSR, crosstalk between SA and oxylipin pathways, or a combination of both outcomese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“dampening of P19 responses thus likely results from lower expression of the VSR, crosstalk between SA and oxylipin pathways, or a combination of both outcomes”
t0“Nicotiana benthamiana”
Claim · model-written summary
Exogenous ascorbic acid improved plant biomass quality during VLP production.
- Taxon
- Nicotiana benthamianaNicotiana benthamianat0
- Treatment
- exogenous application of ascorbic acide0
- Outcome
- plant biomass qualitye0
- Direction
- improvese0
- Qualifier
- during production of VLPse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“exogenous application of ascorbic acid improves plant biomass quality during production of VLPs”
t0“Nicotiana benthamiana”
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See all 29 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.