Abstract
BACKGROUND: Crocus sativus is a triploid sterile plant with long red stigmas which form commercial saffron. Saffron is the site for synthesis and accumulation of apocarotenoids like crocin, picrocrin and safranal which are responsible for its color, flavour and aroma making it world's most expensive spice. These compounds are formed by oxidative cleavage of zeaxanthin by carotenoid cleavage dioxygenases. Although the biosynthetic pathway of apocarotenoids is known to a considerable extent, the mechanism that regulates its tissue and developmental stage specific expression is not known. RESULTS: In the present work, we identified, cloned and characterized ultrapetala transcription factor called CsULT1 from Crocus. The gene contains an 80 amino acid long conserved SAND domain. The CsULT1 transcript was more abundant in stigma and showed increase in expression from pre anthesis stage till anthesis and decreased in post anthesis stage which corroborated with the accumulation pattern of crocin indicating its possible role in regulation of apocarotenoid biosynthesis. CsULT1 was found to be transcriptionally active and localized in nucleus. Its expression is induced in response to phytohormones like auxin, methyljasmonate and salicylic acid. Overexpression of CsULT1 in Crocus calli resulted in enhanced expression of key pathway genes like phytoene synthase (PSY), phytoene desaturase (PDS), beta carotene hydroxylase (BCH) and carotenoid cleavage dioxygenases (CCDs) indicating its role in regulation of apocarotenoid biosynthesis. CONCLUSION: This work presents first report on isolation and characterization of ultrapetala gene from Crocus. Our results suggest that CsULT1 is a novel regulator of Crocus apocarotenoid biosynthesis. We show for the first time involvement of plant SAND domain proteins in regulating secondary metabolic pathways.
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Claims 10
Claim · model-written summary
The CsULT1 gene contains an 80 amino acid long conserved SAND domain.
- Outcome
- 80 amino acid long conserved SAND domaine0
CrocusOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The gene contains an 80 amino acid long conserved SAND domain”
t0“Crocus”
Claim · model-written summary
The CsULT1 transcript was more abundant in stigma.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The CsULT1 transcript was more abundant in stigma”
t0“Crocus”
Claim · model-written summary
CsULT1 expression increased from the pre anthesis stage till anthesis.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“showed increase in expression from pre anthesis stage till anthesis”
e1“The CsULT1 transcript”
t0“Crocus”
Claim · model-written summary
The CsULT1 expression pattern corroborated the accumulation pattern of crocin.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“which corroborated with the accumulation pattern of crocin”
e1“The CsULT1 transcript”
t0“Crocus”
Claim · model-written summary
CsULT1 was transcriptionally active and localized in the nucleus.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“CsULT1 was found to be transcriptionally active and localized in nucleus”
t0“Crocus”
Claim · model-written summary
CsULT1 expression was induced by the phytohormones auxin, methyljasmonate and salicylic acid.
- Treatment
- phytohormones like auxin, methyljasmonate and salicylic acide0
- Outcome
- expressione0
- Direction
- inducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Its expression is induced in response to phytohormones like auxin, methyljasmonate and salicylic acid”
t0“Crocus”
Claim · model-written summary
Overexpression of CsULT1 in Crocus calli enhanced expression of the pathway genes PSY, PDS and BCH.
- Organ / stage
- callie0
- Treatment
- Overexpression of CsULT1e0
- Gene
- phytoene synthase (PSY), phytoene desaturase (PDS), beta carotene hydroxylase (BCH)e0
- Outcome
- expression of key pathway genese0
- Direction
- enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Overexpression of CsULT1 in Crocus calli resulted in enhanced expression of key pathway genes like phytoene synthase (PSY), phytoene desaturase (PDS), beta carotene hydroxylase (BCH) and carotenoid cleavage dioxygenases (CCDs)”
Claim · model-written summary
Overexpression of CsULT1 in Crocus calli enhanced expression of the carotenoid cleavage dioxygenase genes.
- Organ / stage
- callie0
- Treatment
- Overexpression of CsULT1e0
- Gene
- carotenoid cleavage dioxygenases (CCDs)e0
- Outcome
- expression of key pathway genese0
- Direction
- enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Overexpression of CsULT1 in Crocus calli resulted in enhanced expression of key pathway genes like phytoene synthase (PSY), phytoene desaturase (PDS), beta carotene hydroxylase (BCH) and carotenoid cleavage dioxygenases (CCDs)”
Claim · model-written summary
The authors suggest that CsULT1 is a novel regulator of Crocus apocarotenoid biosynthesis.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“CsULT1 is a novel regulator of Crocus apocarotenoid biosynthesis”
Claim · model-written summary
The authors show involvement of plant SAND domain proteins in regulating secondary metabolic pathways.
Verbatim
e0“involvement of plant SAND domain proteins in regulating secondary metabolic pathways”