Abstract
Homeodomain-leucine zipper proteins constitute a family of transcription factors found only in plants. Expression patterns of the sunflower homeobox-leucine zipper gene Hahb-10 (Helianthus annuus homeobox-10), that belongs to the HD-Zip II subfamily, were analysed. Northern blots showed that Hahb-10 is expressed primarily in mature leaves, although expression is clearly detectable in younger leaves and also in stems. Considerably higher expression levels were detected in etiolated seedlings compared with light-grown seedlings. Induction of Hahb-10 expression was observed when seedlings were subjected to treatment with gibberellins. Transgenic Arabidopsis thaliana plants that express Hahb-10 under the 35S cauliflower mosaic virus promoter show special phenotypic characteristics such as darker cotyledons and planar leaves. A reduction in the life cycle of about 25% allowing earlier seed collection was also observed, and this phenomenon is clearly related to a shortened flowering time. When the number of plants per pot increased, the difference in developmental rate between transgenic and non-transformed individuals became larger. After gibberellin treatment, the relative difference in life cycle duration was considerably reduced. Several light-regulated genes have been tested as possible target genes of Hahb-10. One of them, PsbS, shows a different response to illumination conditions in transgenic plants compared with the response in wild-type plants while the other genes behave similarly in both genotypes. We propose that Hahb-10 functions in a signalling cascade(s) that control(s) plant responses to light quality and quantity, and may also be involved in gibberellin transduction pathways.
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Claims 9
Claim · model-written summary
Hahb-10 expression was greatest in mature leaves.
- Taxon
- sunflower
Helianthus annuust0 - Organ / stage
- mature leavese0
- Gene
- Hahb-10e0
- Outcome
- expressed primarily in mature leavese0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Hahb-10 is expressed primarily in mature leaves, although expression is clearly detectable in younger leaves and also in stems”
t0“Sunflower”
Claim · model-written summary
Etiolated seedlings had considerably higher Hahb-10 expression than light-grown seedlings.
- Taxon
- sunflowerHelianthus annuust0
- Organ / stage
- etiolated seedlingse0
- Gene
- Hahb-10t0
- Outcome
- expression levelse0
- Direction
- highere0
- Comparator
- light-grown seedlingse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Considerably higher expression levels were detected in etiolated seedlings compared with light-grown seedlings”
t0“Hahb-10, a Sunflower”
Claim · model-written summary
Gibberellin treatment induced Hahb-10 expression.
- Taxon
- sunflowerHelianthus annuust0
- Treatment
- gibberellinse0
- Gene
- Hahb-10e0
- Outcome
- Hahb-10 expressione0
- Direction
- Inductione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Induction of Hahb-10 expression was observed when seedlings were subjected to treatment with gibberellins”
t0“Sunflower”
Claim · model-written summary
Hahb-10-expressing Arabidopsis had darker cotyledons and planar leaves.
- Taxon
- Arabidopsis thaliana
Arabidopsis thalianae0 - Gene
- Hahb-10e0
- Outcome
- darker cotyledons and planar leavese0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Transgenic Arabidopsis thaliana plants that express Hahb-10 under the 35S cauliflower mosaic virus promoter show special phenotypic characteristics such as darker cotyledons and planar leaves”
Claim · model-written summary
Hahb-10-expressing plants had an approximately 25% shorter life cycle associated with earlier flowering.
- Taxon
- ArabidopsisArabidopsist0
- Gene
- Hahb-10t0
- Outcome
- life cyclee0
- Direction
- reductione0
- Value
- about 25%e0
- Qualifier
- shortened flowering timee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A reduction in the life cycle of about 25% allowing earlier seed collection was also observed, and this phenomenon is clearly related to a shortened flowering time”
t0“Hahb-10, a Sunflower Homeobox-Leucine Zipper Gene, is Regulated by Light Quality and Quantity, and Promotes Early Flowering when Expressed in Arabidopsis”
Claim · model-written summary
Higher plant density enlarged the developmental rate difference between transgenic and non-transformed plants.
- Taxon
- ArabidopsisArabidopsist0
- Outcome
- difference in developmental ratee0
- Direction
- largere0
- Comparator
- non-transformed individualse0
- Setting
- plants per pote0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When the number of plants per pot increased, the difference in developmental rate between transgenic and non-transformed individuals became larger”
t0“in Arabidopsis”
Claim · model-written summary
Gibberellin treatment reduced the relative life cycle duration difference.
- Taxon
- ArabidopsisArabidopsist0
- Treatment
- gibberellin treatmente0
- Outcome
- relative difference in life cycle duratione0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“After gibberellin treatment, the relative difference in life cycle duration was considerably reduced”
t0“in Arabidopsis”
Claim · model-written summary
PsbS responded differently to illumination in transgenic versus wild-type plants.
- Taxon
- ArabidopsisArabidopsist0
- Gene
- PsbSe0
- Outcome
- response to illumination conditionse0
- Comparator
- wild-type plantse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“PsbS, shows a different response to illumination conditions in transgenic plants compared with the response in wild-type plants”
t0“in Arabidopsis”
Claim · model-written summary
Other tested light-regulated genes behaved similarly in transgenic and wild-type plants.
- Taxon
- ArabidopsisArabidopsist0
- Outcome
- other genes behave similarly in both genotypese0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the other genes behave similarly in both genotypes”
t0“in Arabidopsis”
The same questions in other papers
class · molecular: expression · Helianthus annuus (common sunflower)Results agree
1 paper in the same direction as this paper
- positive
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.