Abstract
BACKGROUND AND AIMS: The clone EMB-2 of the interspecific hybrid Helianthus annuus x H. tuberosus provides an interesting system to study molecular and physiological aspects of somatic embryogenesis. Namely, in addition to non-epiphyllous (NEP) leaves that expand normally, EMB-2 produces epiphyllous (EP) leaves bearing embryos on the adaxial surface. This clone was used to investigate if the ectopic expression of H. annuus LEAFY COTYLEDON1-LIKE (Ha-L1L) gene and auxin activity are correlated with the establishment of embryogenic competence. METHODS: Ha-L1L expression was evaluated by semi-quantitative RT-PCR and in situ hybridization. The endogenous level and spatial distribution of free indole-3-acetic acid (IAA) were estimated by a capillary gas chromatography-mass spectrometry-selected ion monitoring method and an immuno-cytochemical approach. KEY RESULTS: Ectopic expression of Ha-L1L was detected in specific cell domains of the adaxial epidermis of EP leaves prior to the development of ectopic embryos. Ha-L1L was expressed rapidly when NEP leaves were induced to regenerate somatic embryos by in vitro culture. Differences in auxin distribution pattern rather than in absolute level were observed between EP and A-2 leaves. More precisely, a strong IAA immuno-signal was detected in single cells or in small groups of cells along the epidermis of EP leaves and accompanied the early stages of embryo development. Changes in auxin level and distribution were observed in NEP leaves induced to regenerate by in vitro culture. Exogenous auxin treatments lightly influenced Ha-L1L transcript levels in spite of an enhancement of the regeneration frequency. CONCLUSIONS: In EP leaves, Ha-L1L activity marks the putative founder cells of ectopic embryos. Although the ectopic expression of Ha-L1L seems to be not directly mediated by auxin levels per se, it was demonstrated that localized Ha-L1L expression and IAA accumulation in leaf epidermis domains represent early events of somatic embryogenesis displayed by the epiphyllous EMB-2 clone.
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Claims 11
Claim · model-written summary
EMB-2 formed embryos on epiphyllous leaf surfaces.
- Taxon
- Helianthus annuus x H. tuberosus
Helianthus annuuse1 - Material
- EMB-2e0
- Organ / stage
- epiphyllous (EP) leavese0
- Outcome
- leaves bearing embryos on the adaxial surfacee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“EMB-2 produces epiphyllous (EP) leaves bearing embryos on the adaxial surface”
e1“interspecific hybrid Helianthus annuus x H. tuberosus”
Claim · model-written summary
Ha-L1L was ectopically expressed in EP leaf epidermal cell domains before embryo development.
- Taxon
- Helianthus annuus x H. tuberosusHelianthus annuuse1
- Organ / stage
- adaxial epidermis of EP leavese0
- Gene
- Ha-L1Le0
- Outcome
- Ectopic expression of Ha-L1Le0
- Qualifier
- prior to the development of ectopic embryose0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ectopic expression of Ha-L1L was detected in specific cell domains of the adaxial epidermis of EP leaves prior to the development of ectopic embryos”
e1“interspecific hybrid Helianthus annuus x H. tuberosus”
Claim · model-written summary
Ha-L1L was rapidly expressed in NEP leaves induced to regenerate embryos in culture.
- Taxon
- Helianthus annuus x H. tuberosusHelianthus annuuse1
- Organ / stage
- NEP leavese0
- Treatment
- induced to regenerate somatic embryos by in vitro culturee0
- Gene
- Ha-L1Le0
- Outcome
- Ha-L1L was expressede0
- Direction
- rapidlye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ha-L1L was expressed rapidly when NEP leaves were induced to regenerate somatic embryos by in vitro culture”
e1“interspecific hybrid Helianthus annuus x H. tuberosus”
Claim · model-written summary
Auxin distribution differed between EP and A-2 leaves, while absolute level did not.
- Taxon
- Helianthus annuus x H. tuberosusHelianthus annuuse1
- Organ / stage
- EPe0
- Outcome
- auxin distribution patterne0
- Direction
- Differencese0
- Comparator
- A-2 leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Differences in auxin distribution pattern rather than in absolute level were observed between EP and A-2 leaves”
e1“interspecific hybrid Helianthus annuus x H. tuberosus”
Claim · model-written summary
Strong IAA signals appeared in EP leaf epidermal cells during early embryo development.
- Taxon
- Helianthus annuus x H. tuberosusHelianthus annuuse1
- Organ / stage
- epidermis of EP leavese0
- Outcome
- IAA immuno-signale0
- Direction
- stronge0
- Qualifier
- early stages of embryo developmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a strong IAA immuno-signal was detected in single cells or in small groups of cells along the epidermis of EP leaves and accompanied the early stages of embryo development”
e1“interspecific hybrid Helianthus annuus x H. tuberosus”
Claim · model-written summary
In vitro regeneration induction changed auxin level and distribution in NEP leaves.
- Taxon
- Helianthus annuus x H. tuberosusHelianthus annuuse1
- Organ / stage
- NEP leavese0
- Treatment
- induced to regenerate by in vitro culturee0
- Outcome
- auxin level and distributione0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Changes in auxin level and distribution were observed in NEP leaves induced to regenerate by in vitro culture”
e1“interspecific hybrid Helianthus annuus x H. tuberosus”
Claim · model-written summary
Exogenous auxin had little influence on Ha-L1L transcript levels.
- Taxon
- Helianthus annuus x H. tuberosusHelianthus annuuse1
- Treatment
- Exogenous auxin treatmentse0
- Gene
- Ha-L1Le0
- Outcome
- Ha-L1L transcript levelse0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Exogenous auxin treatments lightly influenced Ha-L1L transcript levels”
e1“interspecific hybrid Helianthus annuus x H. tuberosus”
Claim · model-written summary
Exogenous auxin enhanced regeneration frequency.
- Taxon
- Helianthus annuus x H. tuberosusHelianthus annuuse2
- Treatment
- Exogenous auxin treatmentse1
- Outcome
- regeneration frequencye0
- Direction
- enhancemente0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in spite of an enhancement of the regeneration frequency”
e1“Exogenous auxin treatments lightly influenced Ha-L1L transcript levels in spite of an enhancement of the regeneration frequency”
e2“interspecific hybrid Helianthus annuus x H. tuberosus”
Claim · model-written summary
Ha-L1L activity marked putative founder cells of ectopic embryos.
- Taxon
- Helianthus annuus x H. tuberosusHelianthus annuuse1
- Gene
- Ha-L1Le0
- Outcome
- putative founder cells of ectopic embryose0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ha-L1L activity marks the putative founder cells of ectopic embryos”
e1“interspecific hybrid Helianthus annuus x H. tuberosus”
Claim · model-written summary
Ectopic Ha-L1L expression appeared not directly mediated by auxin level.
- Taxon
- Helianthus annuus x H. tuberosusHelianthus annuuse1
- Gene
- Ha-L1Le0
- Compound
- auxine0
- Outcome
- ectopic expression of Ha-L1Le0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ectopic expression of Ha-L1L seems to be not directly mediated by auxin levels per se”
e1“interspecific hybrid Helianthus annuus x H. tuberosus”
Claim · model-written summary
Localized Ha-L1L expression and IAA accumulation were early somatic embryogenesis events.
- Taxon
- Helianthus annuus x H. tuberosusHelianthus annuuse1
- Organ / stage
- leaf epidermis domainse0
- Gene
- Ha-L1Le0
- Outcome
- early events of somatic embryogenesise0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“localized Ha-L1L expression and IAA accumulation in leaf epidermis domains represent early events of somatic embryogenesis”
e1“interspecific hybrid Helianthus annuus x H. tuberosus”
The same questions in other papers
class · growth · Helianthus annuus (common sunflower)Positive and negative results
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