Seed dormancy cycling and the regulation of dormancy mechanisms to time germination in variable field environments

Finch‐Savage, William E.; Footitt, Steven

doi:10.1093/jxb/erw477

Cited by 203 publications

(229 citation statements)

References 101 publications

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“…The DELAY OF GERMINATION1 ( DOG1 ) gene confers dormancy on Arabidopsis seeds and is also induced by drought and ABA (Finch‐Savage & Footitt, ). As expected, expression of DOG1 was induced by NaCl and mannitol in wild‐type seeds but not in aba3‐1 or aba2‐11 mutants (Fig.…”

Section: Resultsmentioning

confidence: 98%

Karrikin‐KAI2 signalling provides Arabidopsis seeds with tolerance to abiotic stress and inhibits germination under conditions unfavourable to seedling establishment

2018

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The control of seed germination in response to environmental conditions is important for plant success. We investigated the role of the karrikin receptor KARRIKIN INSENSITIVE2 (KAI2) in the response of Arabidopsis seeds to osmotic stress, salinity and high temperature. Germination of the kai2 mutant was examined in response to NaCl, mannitol and elevated temperature. The effect of karrikin on germination of wild-type seeds, hypocotyl elongation and the expression of karrikin-responsive genes was also examined in response to such stresses. The kai2 seeds germinated less readily than wild-type seeds and germination was more sensitive to inhibition by abiotic stress. Karrikin-induced KAI2 signalling stimulated germination of wild-type seeds under favourable conditions, but, surprisingly, inhibited germination in the presence of osmolytes or at elevated temperature. By contrast, GA stimulated germination of wild-type seeds and mutants under all conditions. Karrikin induced expression of DLK2 and KUF1 genes and inhibited hypocotyl elongation independently of osmotic stress. Under mild osmotic stress, karrikin enhanced expression of DREB2A, WRKY33 and ERF5 genes, but not ABA signalling genes. Thus, the karrikin-KAI2 signalling system can protect against abiotic stress, first by providing stress tolerance, and second by inhibiting germination under conditions unfavourable to seedling establishment.

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Section: Resultsmentioning

confidence: 98%

Karrikin‐KAI2 signalling provides Arabidopsis seeds with tolerance to abiotic stress and inhibits germination under conditions unfavourable to seedling establishment

2018

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“…A previous seed‐burial experiment conducted at the same field site indicated low seed mortality rates in the soil (~3% after 1 year of burial), which did not differ between the Italian and Swedish genotype (Postma, Lundemo, & Ågren, ). However, as most plants in temperate regions, A. thaliana seeds express an annual dormancy cycle in the seed bank until germination occurs (Baskin & Baskin, ; Finch‐Savage & Footitt, ), and the Italian and Swedish genotypes differ in their dormancy cycling behaviour: The seeds of the Italian genotype buried in Sweden acquired such high dormancy levels that they did not germinate at all 1 year after seed burial (Postma et al., ). Therefore, any recruitment from the seed bank is expected to increase the advantage of the local genotype at this site (cf.…”

Section: Discussionmentioning

confidence: 99%

Among‐year variation in selection during early life stages and the genetic basis of fitness in Arabidopsis thaliana

Postma

Ågren

2018

Molecular Ecology

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Incomplete information regarding both selection regimes and the genetic basis of fitness limits our understanding of adaptive evolution. Among-year variation in the genetic basis of fitness is rarely quantified, and estimates of selection are typically based on single components of fitness, thus potentially missing conflicting selection acting during other life-history stages. Here, we examined among-year variation in selection on a key life-history trait and the genetic basis of fitness covering the whole life cycle in the annual plant Arabidopsis thaliana. We planted freshly matured seeds of >200 recombinant inbred lines (RILs) derived from a cross between two locally adapted populations (Italy and Sweden), and both parental genotypes at the native site of the Swedish population in three consecutive years. We quantified selection against the nonlocal Italian genotype, mapped quantitative trait loci (QTL) for fitness and its components, and quantified selection on timing of germination during different life stages. In all 3 years, the local Swedish genotype outperformed the nonlocal Italian genotype. However, both the contribution of early life stages to relative fitness, and the effects of fitness QTL varied among years. Timing of germination was under conflicting selection through seedling establishment vs. adult survival and fecundity, and both the direction and magnitude of net selection varied among years. Our results demonstrate that selection during early life stages and the genetic basis of fitness can vary markedly among years, emphasizing the need for multiyear studies considering the whole life cycle for a full understanding of natural selection and mechanisms maintaining local adaptation.

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“…Finch-Savage and Footitt (2017) provide an excellent overview of their innovative molecular ecology approach to seed dormancy cycling. They show how gene expression and mutant studies together point to MOTHER OF FT AND TFL1 (MFT) as a likely key regulator of life history variation in seeds (Vaistij et al , 2012; Footitt et al , 2013).…”

Section: Environment Maturation and Control Of Processes Post-sheddingmentioning

confidence: 99%

Seed biology – from lab to field

Penfield

2017

Journal of Experimental Botany

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Seed dormancy cycling and the regulation of dormancy mechanisms to time germination in variable field environments

Cited by 203 publications

References 101 publications

Karrikin‐KAI2 signalling provides Arabidopsis seeds with tolerance to abiotic stress and inhibits germination under conditions unfavourable to seedling establishment

Karrikin‐KAI2 signalling provides Arabidopsis seeds with tolerance to abiotic stress and inhibits germination under conditions unfavourable to seedling establishment

Among‐year variation in selection during early life stages and the genetic basis of fitness in Arabidopsis thaliana

Seed biology – from lab to field

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