Paper · 2026 · Annals of Botany

The LbMUG3-LbSTI regulatory module mediates salt gland development and salinity tolerance in recretohalophyte Limonium bicolor

Jianglu Zhu; Yiyang Feng; Hai Fan; et al.

11
claims
15
verbatim quotes
0
citations
3
research areas
✓
Open access

Abstract

BACKGROUND AND AIMS: Soil salinization severely limits crop productivity worldwide. Halophytes provide important biological resources for identifying genes that confer salinity tolerance. Salt glands, specialized epidermal structures in recretohalophytes like Limonium bicolor, excrete excess Na+, yet their developmental and functional regulation remains poorly understood. METHODS: We focused on LbSTICHEL (LbSTI), a homologue of the Arabidopsis trichome regulator STI, and investigated its function and upstream regulation in L. bicolor. KEY RESULTS: LbSTI was found to be specifically expressed in the salt glands of L. bicolor, as determined by RNA in situ hybridization and GUS histochemical staining driven by the LbSTI promoter. The function of LbSTI was further investigated in L. bicolor. In L. bicolor, plants overexpressing LbSTI produced more salt glands, exhibited increased salt secretion and greater tolerance to salinity stress compared with non-transformed controls. Conversely, LbSTI-knockdown plants generated by virus-induced gene silencing showed opposite phenotypes. Meanwhile, LbSTI increased trichome development and salinity tolerance in wild-type plants and an sti mutant of Arabidopsis, which indicated conservation across species. Furthermore, the upstream regulatory transcription factor LbMUSTANG3 (LbMUG3) was identified to bind to the LbSTI promoter and inhibit the transcription of LbSTI using a yeast one-hybrid and dual-luciferase reporter assay. Further functional validation revealed that LbMUG3 delayed salt gland development in L. bicolor. Additionally, the expression of LbSTI was significantly upregulated in LbMUG3-silenced lines. CONCLUSIONS: The current LbMUG3-LbSTI module may be a useful tool to cultivate plants with salinity tolerance.

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Claims 11

Observationobservedoriginal resultmeasured

Claim · model-written summary

LbSTI was specifically expressed in Limonium bicolor salt glands.

Taxon
L. bicolorLimonium bicolore0
Organ / stage
salt glandse0
Gene
LbSTIe0
Outcome
specifically expressede0

Verbatim

e0

“LbSTI was found to be specifically expressed in the salt glands of L. bicolor”

✓ located verbatim in the source · abstract, characters 554–631 · show in text ↑
Intervention effectobservedoriginal resultpositivemeasured

Claim · model-written summary

LbSTI overexpression increased salt gland number in Limonium bicolor.

Taxon
L. bicolorLimonium bicolore0
Treatment
overexpressing LbSTIe0
Gene
LbSTIe0
Outcome
salt glandse0
Direction
moree0
Comparator
non-transformed controlse0

Verbatim

e0

“In L. bicolor, plants overexpressing LbSTI produced more salt glands, exhibited increased salt secretion and greater tolerance to salinity stress compared with non-transformed controls”

✓ located verbatim in the source · abstract, characters 799–983 · show in text ↑
Intervention effectobservedoriginal resultpositivemeasured

Claim · model-written summary

LbSTI overexpression increased salt secretion in Limonium bicolor.

Taxon
L. bicolorLimonium bicolore0
Treatment
overexpressing LbSTIe0
Gene
LbSTIe0
Outcome
salt secretione0
Direction
increasede0
Comparator
non-transformed controlse0

Verbatim

e0

“In L. bicolor, plants overexpressing LbSTI produced more salt glands, exhibited increased salt secretion and greater tolerance to salinity stress compared with non-transformed controls”

✓ located verbatim in the source · abstract, characters 799–983 · show in text ↑
Intervention effectobservedoriginal resultpositivemeasured

Claim · model-written summary

LbSTI overexpression increased salinity tolerance in Limonium bicolor.

Taxon
L. bicolorLimonium bicolore0
Treatment
overexpressing LbSTIe0
Gene
LbSTIe0
Outcome
tolerance to salinity stresse0
Direction
greatere0
Comparator
non-transformed controlse0

Verbatim

e0

“In L. bicolor, plants overexpressing LbSTI produced more salt glands, exhibited increased salt secretion and greater tolerance to salinity stress compared with non-transformed controls”

✓ located verbatim in the source · abstract, characters 799–983 · show in text ↑
Intervention effectobservedoriginal resultnegativemeasured

Claim · model-written summary

LbSTI silencing produced opposite salt gland, secretion, and tolerance phenotypes.

Taxon
Limonium bicolorLimonium bicolort0
Treatment
virus-induced gene silencinge0
Gene
LbSTIe0
Outcome
opposite phenotypese0
Direction
oppositee0

Not reportedComparator

Verbatim

t0

“Limonium bicolor”

✓ located verbatim in the source · title, characters 110–126 · show in text ↑
e0

“LbSTI-knockdown plants generated by virus-induced gene silencing showed opposite phenotypes”

✓ located verbatim in the source · abstract, characters 997–1088 · show in text ↑
Intervention effectobservedoriginal resultpositivemeasured

Claim · model-written summary

LbSTI increased trichome development in Arabidopsis wild type and sti mutant plants.

Taxon
ArabidopsisArabidopsise0
Material
sti mutante0
Treatment
LbSTIe0
Gene
LbSTIe0
Outcome
trichome developmente0
Direction
increasede0

Not reportedComparator

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Arabidopsis
Arabidopsis · Taxon · picture of the genus (one of its species)Original uploader was Brona at en.wikipedia . User:Roepers at nl.wikipedia · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“LbSTI increased trichome development and salinity tolerance in wild-type plants and an sti mutant of Arabidopsis”

✓ located verbatim in the source · abstract, characters 1101–1213 · show in text ↑
Intervention effectobservedoriginal resultpositivemeasured

Claim · model-written summary

LbSTI increased salinity tolerance in Arabidopsis wild type and sti mutant plants.

Taxon
ArabidopsisArabidopsise0
Material
sti mutante0
Treatment
LbSTIe0
Gene
LbSTIe0
Outcome
salinity tolerancee0
Direction
increasede0

Not reportedComparator

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Arabidopsis
Arabidopsis · Taxon · picture of the genus (one of its species)Original uploader was Brona at en.wikipedia . User:Roepers at nl.wikipedia · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“LbSTI increased trichome development and salinity tolerance in wild-type plants and an sti mutant of Arabidopsis”

✓ located verbatim in the source · abstract, characters 1101–1213 · show in text ↑
Observationobservedoriginal resultmeasured

Claim · model-written summary

LbMUG3 bound the LbSTI promoter.

Taxon
Limonium bicolorLimonium bicolort0
Gene
LbMUSTANG3 (LbMUG3)e0
Outcome
bind to the LbSTI promotere0

Verbatim

t0

“Limonium bicolor”

✓ located verbatim in the source · title, characters 110–126 · show in text ↑
e0

“LbMUSTANG3 (LbMUG3) was identified to bind to the LbSTI promoter”

✓ located verbatim in the source · abstract, characters 1318–1382 · show in text ↑
Mechanismobservedoriginal resultnegativemeasured

Claim · model-written summary

LbMUG3 inhibited LbSTI transcription.

Taxon
Limonium bicolorLimonium bicolort0
Gene
LbMUSTANG3 (LbMUG3)e0
Outcome
transcription of LbSTIe0
Direction
inhibite0

Verbatim

t0

“Limonium bicolor”

✓ located verbatim in the source · title, characters 110–126 · show in text ↑
e0

“LbMUSTANG3 (LbMUG3) was identified to bind to the LbSTI promoter and inhibit the transcription of LbSTI”

✓ located verbatim in the source · abstract, characters 1318–1421 · show in text ↑
Mechanismobservedoriginal resultnegativemeasured

Claim · model-written summary

LbMUG3 delayed salt gland development.

Taxon
L. bicolorLimonium bicolore0
Gene
LbMUG3e0
Outcome
salt gland developmente0
Direction
delayede0

Verbatim

e0

“LbMUG3 delayed salt gland development in L. bicolor”

✓ located verbatim in the source · abstract, characters 1527–1578 · show in text ↑
Intervention effectobservedoriginal resultpositivesignificant (as stated)measured

Claim · model-written summary

Silencing LbMUG3 upregulated LbSTI expression.

Taxon
Limonium bicolorLimonium bicolort0
Material
LbMUG3-silenced linese0
Treatment
LbMUG3-silencede0
Gene
LbSTIe0
Outcome
expression of LbSTIe0
Direction
upregulatede0

Not reportedComparator

Verbatim

t0

“Limonium bicolor”

✓ located verbatim in the source · title, characters 110–126 · show in text ↑
e0

“the expression of LbSTI was significantly upregulated in LbMUG3-silenced lines”

✓ located verbatim in the source · abstract, characters 1594–1672 · show in text ↑