Regulation of Seed Germination and Seedling Growth by Chemical Signals from Burning Vegetation

Nelson, David C.; Flematti, Gavin R.; Ghisalberti, Emilio L.; Dixon, Kingsley W.; Smith, Steven M.

doi:10.1146/annurev-arplant-042811-105545

Cited by 258 publications

(225 citation statements)

References 126 publications

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“…The chemical structures of karrikins and strigolactones share a common butenolide moiety (18) (Figs. 1 and 2A), and the F-box protein MORE AXILLARY BRANCHES 2 (MAX2) is implicated as a downstream target for signaling by both karrikins and strigolactones (8).…”

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confidence: 99%

Smoke-derived karrikin perception by the α/β-hydrolase KAI2 from Arabidopsis

Guo

Zheng

Clair

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

161

185

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Genetic studies in Arabidopsis implicate an α/β-hydrolase, KARRIKIN-INSENSITIVE 2 (KAI2) as a receptor for karrikins, germination-promoting butenolide small molecules found in the smoke of burned plants. However, direct biochemical evidence for the interaction between KAI2 and karrikin and for the mechanism of downstream signaling by a KAI2-karrikin complex remain elusive. We report crystallographic analyses and ligand-binding experiments for KAI2 recognition of karrikins. The karrikin-1 (KAR 1 ) ligand sits in the opening to the active site abutting a helical domain insert but distal from the canonical catalytic triad (Ser95-His246-Asp217) of α/β-hydrolases, consistent with the lack of detectable hydrolytic activity by purified KAI2. The closest approach of KAR 1 to Ser95-His246-Asp217 is 3.8 Å from His246. Six aromatic side chains, including His246, encapsulate KAR 1 through geometrically defined aromatic-aromatic interactions. KAR 1 binding induces a conformational change in KAI2 at the active site entrance. A crevice of hydrophobic residues linking the polar edge of KAR 1 and the helical domain insert suggests that KAI2-KAR 1 creates a contiguous interface for binding signaling partners in a liganddependent manner.plant signaling | wildfires | seed dormancy W ildfires recycle plant environments by releasing nutrients stored in plant tissues and often stimulate the germination of quiescent seeds (1). Germination-stimulating compounds, generated in the smoke of burning plants, include a seed dormancybreaking compound 3-methyl-2H-furo[2,3-c]pyran-2-one, a butenolide named karrikinolide-1 or karrikin-1 (KAR 1 ) (2). Previous reports reveal KAR 1 structure-activity relationships (SARs) and features of the physiological mode of action (3-7). Karrikinsinsensitive (kai) mutants in the model plant Arabidopsis thaliana identify some of the genetic components underlying karrikins' perception and signaling (8,9). Seeds of kai2 mutants are insensitive to KAR 1 -induced germination, suggesting that the KAI2 gene product is essential for KAR 1 perception and/or signal transduction (8, 9). KAI2, also known as HYPOSENSITIVE TO LIGHT (HTL) (10), is a member of the α/β-hydrolase superfamily commonly containing a catalytic triad, Ser(Cys)-His-Asp (11). Notably, several other members of the α/β-hydrolase superfamily sense, bind, and/or catalytically modify phytohormones. For example, the α/β-hydrolase SALICYLIC ACID-BINDING PROTEIN 2 (SABP2) converts methyl salicylate to salicylic acid through its esterase activity. The product of the reaction, salicylic acid, retains relatively high binding affinity to SABP2, which inhibits SABP2 catalytic activity and fine tunes salicylic acid levels (12). Another α/β-hydrolase family member GIBBERELLIN-INSENSITIVE DWARF 1 (GID1) lacks the highly conserved catalytic triad, but serves as the receptor of gibberellins (13,14). These previous studies have led to speculation that the KAI2 protein might be the receptor of karrikins (8,9). This hypothesis is supported by the recent discovery that ano...

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mentioning

confidence: 99%

Smoke-derived karrikin perception by the α/β-hydrolase KAI2 from Arabidopsis

Guo

Zheng

Clair

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

161

185

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“…Based on the results, SGV composition cannot be established. As it was mentioned in the Introduction, SGV probably comprise karrikins, TMB, nitric oxide, ethylene, nitrate and cyanohydrins of physiological activity [10][11][12][13][14][15][16].…”

Section: Discussionmentioning

confidence: 99%

“…Once taken, the material was carefully washed, sealed in laboratory vials filled with 10-15 cm 3 of water and shaken for 24 h. The conductivity was measured (L s1 ), then samples were boiled at 100°C for 15 min, shaken for 24 hours and additive used in agriculture, remediation and reforestations is the source of biologically active karrikins [17]. Which makes the matter more complex, other molecules should be considered, namely nitric oxide, ethylene, nitrate and cyanohydrins, which have been known as the smoke compounds and have the ability to stimulate seed germination in certain plant species [10,12,18].…”

Section: Germination Course -Laboratory Experimentsmentioning

confidence: 99%

Swailing affects seed germination of plants of European bio-and agricenosis in a different way

Bączek-Kwinta

2017

Open Life Sciences

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Swailing as a part of agricultural practice is an illegal habit in many European countries. The indirect effect of swailing is the emission of volatiles (SGV), hence the aim of the study was to identify their impact to seeds of different species occurring or grown Europe. It was carried out on seeds of 29 species of 10 botanical families within the angiosperms. The response to SGV was more or less differentiated within a family, and even within the species, e.g. in the case of tomato. The stimulation of germination and/or increased seedling vigour was established in celery, green- and red-leafed basil, white and red cabbage, white clover and wild thyme. The same effect was noticed for the seeds of stratified broadleaf plantain and the positively photoblastic seeds of German chamomile germinated in darkness. The inhibition of seed germination and/ or reduced seedling vigour was demonstrated in case of caraway, dill and forget-me-not. Similar results were obtained in the experiments carried out in vitro and in the soil, hence it can be assumed that the indirect impact of SGV on plant habitat composition is likely. The interaction of SGV compounds with seed testa and seed phytohormones is discussed.

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“…Accordingly, a large number of plant species have evolved the ability to perceive and respond to fire events. A prominent adaptation among species from fire-prone regions is the promotion of seed germination following exposure to smoke, and chemicals therein (Van Staden et al 2000;Nelson et al 2012).…”

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confidence: 99%

From little things big things grow: karrikins and new directions in plant development

Waters¹

2017

Functional Plant Biol.

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Abstract. Karrikins are a family of compounds generated via the incomplete combustion of plant matter. Since their discovery as seed germination stimulants in 2004, a great deal has been learned about the chemistry and the biological mode of action of karrikins. Much interest and progress have stemmed from the structural similarity of karrikins to that of strigolactones -the shoot branching hormone. This review will provide a historical account of some of the more significant discoveries in this area of plant biology. It will discuss how the study of these abiotic signalling molecules, combined with advances in our understanding of strigolactones, has led us towards the discovery of new mechanisms that regulate plant growth and development.

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Regulation of Seed Germination and Seedling Growth by Chemical Signals from Burning Vegetation

Cited by 258 publications

References 126 publications

Smoke-derived karrikin perception by the α/β-hydrolase KAI2 from Arabidopsis

Smoke-derived karrikin perception by the α/β-hydrolase KAI2 from Arabidopsis

Swailing affects seed germination of plants of European bio-and agricenosis in a different way

From little things big things grow: karrikins and new directions in plant development

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