Abstract
Biosynthesis of the alkaloid nicotine in Nicotiana species is induced by insect damage and jasmonate application. To probe the transcriptional regulation of the nicotine pathway, we constructed two subtracted cDNA libraries from methyl jasmonate (MeJA)-treated Nicotiana benthamiana roots directly in a viral vector suitable for virus-induced gene silencing (VIGS). Sequencing of cDNA inserts produced a data set of 3271 expressed sequence tags (ESTs; 1898 unigenes), which were enriched in jasmonate-responsive genes, and included 69 putative transcription factors (TFs). After a VIGS screen to determine their effect on nicotine metabolism, six TFs from three different TF families altered constitutive and MeJA-induced leaf nicotine levels. VIGS of a basic helix-loop-helix (bHLH) TF, NbbHLH3, and an auxin response factor TF, NbARF1, increased nicotine content compared with control plants; silencing the bHLH family members, NbbHLH1 and NbbHLH2, an ethylene response factor TF, NbERF1, and a homeobox domain-like TF, NbHB1, reduced nicotine levels. Transgenic N. benthamiana plants overexpressing NbbHLH1 or NbbHLH2 showed increased leaf nicotine levels compared with vector controls. RNAi silencing led to both reduced nicotine and decreased levels of transcript encoding of enzymes of the nicotine pathway. Electrophoretic mobility shift assays showed that recombinant NbbHLH1 and NbbHLH2 directly bind G-box elements identified from the putrescine N-methyltransferase promoter. We conclude that NbbHLH1 and NbbHLH2 function as positive regulators in the jasmonate activation of nicotine biosynthesis.
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Claims 15
Claim · model-written summary
Sequencing produced 3271 ESTs representing 1898 unigenes, enriched for jasmonate-responsive genes.
- Taxon
- Nicotiana benthamiana
Nicotiana benthamianat0 - Outcome
- expressed sequence tagse0
- Value
- 3271e0
- Qualifier
- 1898 unigenese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Sequencing of cDNA inserts produced a data set of 3271 expressed sequence tags (ESTs; 1898 unigenes), which were enriched in jasmonate-responsive genes, and included 69 putative transcription factors (TFs).”
t0“A functional genomics screen identifies diverse transcription factors that regulate alkaloid biosynthesis in Nicotiana benthamiana”
Claim · model-written summary
The sequence set included 69 putative transcription factors.
- Taxon
- Nicotiana benthamianaNicotiana benthamianat0
- Outcome
- putative transcription factorse0
- Value
- 69e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Sequencing of cDNA inserts produced a data set of 3271 expressed sequence tags (ESTs; 1898 unigenes), which were enriched in jasmonate-responsive genes, and included 69 putative transcription factors (TFs).”
t0“A functional genomics screen identifies diverse transcription factors that regulate alkaloid biosynthesis in Nicotiana benthamiana”
Claim · model-written summary
VIGS screening found six transcription factors from three families that altered leaf nicotine levels.
- Taxon
- Nicotiana benthamianaNicotiana benthamianat0
- Outcome
- leaf nicotine levelse0
- Value
- six TFse0
- Qualifier
- three different TF familiese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“After a VIGS screen to determine their effect on nicotine metabolism, six TFs from three different TF families altered constitutive and MeJA-induced leaf nicotine levels.”
t0“A functional genomics screen identifies diverse transcription factors that regulate alkaloid biosynthesis in Nicotiana benthamiana”
Claim · model-written summary
Silencing NbbHLH3 increased nicotine content in N. benthamiana leaves.
- Taxon
- Nicotiana benthamianaNicotiana benthamianat0
- Organ / stage
- leafe1
- Treatment
- VIGSe0
- Gene
- NbbHLH3e0
- Outcome
- nicotine contente0
- Direction
- increasede0
- Comparator
- control plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“VIGS of a basic helix-loop-helix (bHLH) TF, NbbHLH3, and an auxin response factor TF, NbARF1, increased nicotine content compared with control plants; silencing the bHLH family members, NbbHLH1 and NbbHLH2, an ethylene response factor TF, NbERF1, and a homeobox domain-like TF, NbHB1, reduced nicotine levels.”
e1“After a VIGS screen to determine their effect on nicotine metabolism, six TFs from three different TF families altered constitutive and MeJA-induced leaf nicotine levels.”
t0“A functional genomics screen identifies diverse transcription factors that regulate alkaloid biosynthesis in Nicotiana benthamiana”
Claim · model-written summary
Silencing NbARF1 increased nicotine content in N. benthamiana leaves.
- Taxon
- Nicotiana benthamianaNicotiana benthamianat0
- Organ / stage
- leafe1
- Treatment
- VIGSe0
- Gene
- NbARF1e0
- Outcome
- nicotine contente0
- Direction
- increasede0
- Comparator
- control plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“VIGS of a basic helix-loop-helix (bHLH) TF, NbbHLH3, and an auxin response factor TF, NbARF1, increased nicotine content compared with control plants; silencing the bHLH family members, NbbHLH1 and NbbHLH2, an ethylene response factor TF, NbERF1, and a homeobox domain-like TF, NbHB1, reduced nicotine levels.”
e1“After a VIGS screen to determine their effect on nicotine metabolism, six TFs from three different TF families altered constitutive and MeJA-induced leaf nicotine levels.”
t0“A functional genomics screen identifies diverse transcription factors that regulate alkaloid biosynthesis in Nicotiana benthamiana”
Claim · model-written summary
Silencing NbbHLH1 reduced nicotine content in N. benthamiana leaves.
- Taxon
- Nicotiana benthamianaNicotiana benthamianat0
- Organ / stage
- leafe1
- Treatment
- silencinge0
- Gene
- NbbHLH1e0
- Outcome
- nicotine levelse0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“VIGS of a basic helix-loop-helix (bHLH) TF, NbbHLH3, and an auxin response factor TF, NbARF1, increased nicotine content compared with control plants; silencing the bHLH family members, NbbHLH1 and NbbHLH2, an ethylene response factor TF, NbERF1, and a homeobox domain-like TF, NbHB1, reduced nicotine levels.”
e1“After a VIGS screen to determine their effect on nicotine metabolism, six TFs from three different TF families altered constitutive and MeJA-induced leaf nicotine levels.”
t0“A functional genomics screen identifies diverse transcription factors that regulate alkaloid biosynthesis in Nicotiana benthamiana”
Claim · model-written summary
Silencing NbbHLH2 reduced nicotine content in N. benthamiana leaves.
- Taxon
- Nicotiana benthamianaNicotiana benthamianat0
- Organ / stage
- leafe1
- Treatment
- silencinge0
- Gene
- NbbHLH2e0
- Outcome
- nicotine levelse0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“VIGS of a basic helix-loop-helix (bHLH) TF, NbbHLH3, and an auxin response factor TF, NbARF1, increased nicotine content compared with control plants; silencing the bHLH family members, NbbHLH1 and NbbHLH2, an ethylene response factor TF, NbERF1, and a homeobox domain-like TF, NbHB1, reduced nicotine levels.”
e1“After a VIGS screen to determine their effect on nicotine metabolism, six TFs from three different TF families altered constitutive and MeJA-induced leaf nicotine levels.”
t0“A functional genomics screen identifies diverse transcription factors that regulate alkaloid biosynthesis in Nicotiana benthamiana”
Claim · model-written summary
Silencing NbERF1 reduced nicotine content in N. benthamiana leaves.
- Taxon
- Nicotiana benthamianaNicotiana benthamianat0
- Organ / stage
- leafe1
- Treatment
- silencinge0
- Gene
- NbERF1e0
- Outcome
- nicotine levelse0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“VIGS of a basic helix-loop-helix (bHLH) TF, NbbHLH3, and an auxin response factor TF, NbARF1, increased nicotine content compared with control plants; silencing the bHLH family members, NbbHLH1 and NbbHLH2, an ethylene response factor TF, NbERF1, and a homeobox domain-like TF, NbHB1, reduced nicotine levels.”
e1“After a VIGS screen to determine their effect on nicotine metabolism, six TFs from three different TF families altered constitutive and MeJA-induced leaf nicotine levels.”
t0“A functional genomics screen identifies diverse transcription factors that regulate alkaloid biosynthesis in Nicotiana benthamiana”
Claim · model-written summary
Silencing NbHB1 reduced nicotine content in N. benthamiana leaves.
- Taxon
- Nicotiana benthamianaNicotiana benthamianat0
- Organ / stage
- leafe1
- Treatment
- silencinge0
- Gene
- NbHB1e0
- Outcome
- nicotine levelse0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“VIGS of a basic helix-loop-helix (bHLH) TF, NbbHLH3, and an auxin response factor TF, NbARF1, increased nicotine content compared with control plants; silencing the bHLH family members, NbbHLH1 and NbbHLH2, an ethylene response factor TF, NbERF1, and a homeobox domain-like TF, NbHB1, reduced nicotine levels.”
e1“After a VIGS screen to determine their effect on nicotine metabolism, six TFs from three different TF families altered constitutive and MeJA-induced leaf nicotine levels.”
t0“A functional genomics screen identifies diverse transcription factors that regulate alkaloid biosynthesis in Nicotiana benthamiana”
Claim · model-written summary
Overexpression of NbbHLH1 increased leaf nicotine relative to vector controls.
- Taxon
- N. benthamianaNicotiana benthamianae0
- Treatment
- overexpressing NbbHLH1 or NbbHLH2e0
- Gene
- NbbHLH1e0
- Outcome
- leaf nicotine levelse0
- Direction
- increasede0
- Comparator
- vector controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Transgenic N. benthamiana plants overexpressing NbbHLH1 or NbbHLH2 showed increased leaf nicotine levels compared with vector controls.”
Claim · model-written summary
Overexpression of NbbHLH2 increased leaf nicotine relative to vector controls.
- Taxon
- N. benthamianaNicotiana benthamianae0
- Treatment
- overexpressing NbbHLH1 or NbbHLH2e0
- Gene
- NbbHLH2e0
- Outcome
- leaf nicotine levelse0
- Direction
- increasede0
- Comparator
- vector controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Transgenic N. benthamiana plants overexpressing NbbHLH1 or NbbHLH2 showed increased leaf nicotine levels compared with vector controls.”
Claim · model-written summary
RNAi silencing reduced nicotine levels.
- Taxon
- Nicotiana benthamianaNicotiana benthamianat0
- Treatment
- RNAi silencinge0
- Outcome
- nicotinee0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“RNAi silencing led to both reduced nicotine and decreased levels of transcript encoding of enzymes of the nicotine pathway.”
t0“A functional genomics screen identifies diverse transcription factors that regulate alkaloid biosynthesis in Nicotiana benthamiana”
Claim · model-written summary
RNAi silencing decreased transcripts encoding nicotine pathway enzymes.
- Taxon
- Nicotiana benthamianaNicotiana benthamianat0
- Treatment
- RNAi silencinge0
- Outcome
- levels of transcript encoding of enzymes of the nicotine pathwaye0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“RNAi silencing led to both reduced nicotine and decreased levels of transcript encoding of enzymes of the nicotine pathway.”
t0“A functional genomics screen identifies diverse transcription factors that regulate alkaloid biosynthesis in Nicotiana benthamiana”
Claim · model-written summary
NbbHLH1 and NbbHLH2 bind G-box elements in the putrescine N-methyltransferase promoter.
- Taxon
- Nicotiana benthamianaNicotiana benthamianat0
- Gene
- NbbHLH1 and NbbHLH2e0
- Outcome
- directly bind G-box elementse0
- Qualifier
- putrescine N-methyltransferase promotere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Electrophoretic mobility shift assays showed that recombinant NbbHLH1 and NbbHLH2 directly bind G-box elements identified from the putrescine N-methyltransferase promoter.”
t0“A functional genomics screen identifies diverse transcription factors that regulate alkaloid biosynthesis in Nicotiana benthamiana”
Claim · model-written summary
NbbHLH1 and NbbHLH2 are positive regulators of jasmonate-induced nicotine biosynthesis.
- Taxon
- Nicotiana benthamianaNicotiana benthamianat0
- Gene
- NbbHLH1 and NbbHLH2e0
- Outcome
- nicotine biosynthesise0
- Qualifier
- jasmonate activatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“We conclude that NbbHLH1 and NbbHLH2 function as positive regulators in the jasmonate activation of nicotine biosynthesis.”
t0“A functional genomics screen identifies diverse transcription factors that regulate alkaloid biosynthesis in Nicotiana benthamiana”
The same questions in other papers
loss of function · molecular: metabolites · Nicotiana benthamianaPositive and negative results
9 papers in the same direction as this paper · 25 in the opposite direction
- negative
- negative
- no effect
31 papers more in this group
See all 35 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.