Abstract
The micropylar endosperm cap covering the radicle in the mature seeds of most angiosperms acts as a constraint that regulates seed germination. Here, we report on a comparative seed biology study with the close Brassicaceae relatives Lepidium sativum and Arabidopsis thaliana showing that ethylene biosynthesis and signaling regulate seed germination by a mechanism that requires the coordinated action of the radicle and the endosperm cap. The larger seed size of Lepidium allows direct tissue-specific biomechanical, biochemical, and transcriptome analyses. We show that ethylene promotes endosperm cap weakening of Lepidium and endosperm rupture of both species and that it counteracts the inhibitory action of abscisic acid (ABA) on these two processes. Cross-species microarrays of the Lepidium micropylar endosperm cap and the radicle show that the ethylene-ABA antagonism involves both tissues and has the micropylar endosperm cap as a major target. Ethylene counteracts the ABA-induced inhibition without affecting seed ABA levels. The Arabidopsis loss-of-function mutants ACC oxidase2 (aco2; ethylene biosynthesis) and constitutive triple response1 (ethylene signaling) are impaired in the 1-aminocyclopropane-1-carboxylic acid (ACC)-mediated reversion of the ABA-induced inhibition of seed germination. Ethylene production by the ACC oxidase orthologs Lepidium ACO2 and Arabidopsis ACO2 appears to be a key regulatory step. Endosperm cap weakening and rupture are promoted by ethylene and inhibited by ABA to regulate germination in a process conserved across the Brassicaceae.
Abstract from the paper’s OpenAlex record; open copy licensed cc-by. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 9
Claim · model-written summary
Ethylene promotes Lepidium endosperm cap weakening.
- Taxon
- Lepidium sativum
Lepidium sativume1 - Treatment
- ethylenee0
- Outcome
- endosperm cap weakeninge0
- Direction
- promotese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ethylene promotes endosperm cap weakening of Lepidium”
e1“Lepidium sativum and Arabidopsis thaliana”
Claim · model-written summary
Ethylene promotes endosperm rupture in Lepidium and Arabidopsis.
- Taxon
- Lepidium sativum and Arabidopsis thaliana
Arabidopsis thalianaLepidium sativume1 - Treatment
- ethylenee0
- Outcome
- endosperm rupturee0
- Direction
- promotese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ethylene promotes endosperm cap weakening of Lepidium and endosperm rupture of both species”
e1“Lepidium sativum and Arabidopsis thaliana”
Claim · model-written summary
Ethylene counteracts ABA inhibition of endosperm cap weakening and rupture.
- Taxon
- Lepidium sativum and Arabidopsis thalianaArabidopsis thalianaLepidium sativume1
- Outcome
- inhibitory actione0
- Direction
- counteractse0
- Comparator
- abscisic acid (ABA)e0
Not reportedTreatment
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“it counteracts the inhibitory action of abscisic acid (ABA) on these two processes”
e1“Lepidium sativum and Arabidopsis thaliana”
Claim · model-written summary
The ethylene-ABA antagonism involves the micropylar endosperm cap and radicle, with the cap a major target.
- Taxon
- Lepidium sativum and Arabidopsis thalianaArabidopsis thalianaLepidium sativume2
- Organ / stage
- micropylar endosperm cap and the radiclee1
- Outcome
- ethylene-ABA antagonisme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the ethylene-ABA antagonism involves both tissues and has the micropylar endosperm cap as a major target”
e1“the Lepidium micropylar endosperm cap and the radicle”
e2“Lepidium sativum and Arabidopsis thaliana”
Claim · model-written summary
Ethylene counteracts ABA-induced inhibition without changing seed ABA levels.
- Taxon
- Lepidium sativum and Arabidopsis thalianaArabidopsis thalianaLepidium sativume1
- Treatment
- Ethylenee0
- Outcome
- seed ABA levelse0
- Direction
- without affectinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ethylene counteracts the ABA-induced inhibition without affecting seed ABA levels”
e1“Lepidium sativum and Arabidopsis thaliana”
Claim · model-written summary
Arabidopsis aco2 mutants were impaired in ACC-mediated reversal of ABA inhibition of germination.
- Taxon
- ArabidopsisArabidopsise0
- Gene
- ACC oxidase2e0
- Outcome
- impaired in the 1-aminocyclopropane-1-carboxylic acid (ACC)-mediated reversion of the ABA-induced inhibition of seed germinatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The Arabidopsis loss-of-function mutants ACC oxidase2 (aco2; ethylene biosynthesis) and constitutive triple response1 (ethylene signaling) are impaired in the 1-aminocyclopropane-1-carboxylic acid (ACC)-mediated reversion of the ABA-induced inhibition of seed germination”
Claim · model-written summary
Arabidopsis constitutive triple response1 mutants were impaired in ACC-mediated reversal of ABA inhibition of germination.
- Taxon
- ArabidopsisArabidopsise0
- Gene
- constitutive triple response1e0
- Outcome
- impaired in the 1-aminocyclopropane-1-carboxylic acid (ACC)-mediated reversion of the ABA-induced inhibition of seed germinatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The Arabidopsis loss-of-function mutants ACC oxidase2 (aco2; ethylene biosynthesis) and constitutive triple response1 (ethylene signaling) are impaired in the 1-aminocyclopropane-1-carboxylic acid (ACC)-mediated reversion of the ABA-induced inhibition of seed germination”
Claim · model-written summary
Ethylene production by Lepidium ACO2 and Arabidopsis ACO2 appears to be a key regulatory step.
- Taxon
- Lepidium sativum and Arabidopsis thalianaArabidopsis thalianaLepidium sativume1
- Gene
- Lepidium ACO2 and Arabidopsis ACO2e0
- Outcome
- key regulatory stepe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ethylene production by the ACC oxidase orthologs Lepidium ACO2 and Arabidopsis ACO2 appears to be a key regulatory step”
e1“Lepidium sativum and Arabidopsis thaliana”
Claim · model-written summary
Ethylene promotes and ABA inhibits endosperm cap weakening and rupture across Brassicaceae.
- Taxon
- Lepidium sativum and Arabidopsis thalianaArabidopsis thalianaLepidium sativume1
- Outcome
- Endosperm cap weakening and rupturee0
- Qualifier
- process conserved across the Brassicaceaee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Endosperm cap weakening and rupture are promoted by ethylene and inhibited by ABA to regulate germination in a process conserved across the Brassicaceae”
e1“Lepidium sativum and Arabidopsis thaliana”
The same questions in other papers
ethene · physiology: hormones · Arabidopsis thaliana (thale cress)Positive and negative results
3 papers in the same direction as this paper · 1 in the opposite direction
- positive
- negative
- negative
1 paper more in this group
See all 5 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.