Signal integration in the control of shoot branching

Domagalska, Malgorzata A.; Leyser, Ottoline

doi:10.1038/nrm3088

Cited by 681 publications

(636 citation statements)

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“…Although strigolactones are mobile in the xylem 23 , a cellular transport system is required to deliver strigolactones to dormant buds that are not yet connected to the xylem. This idea is compatible with both current models of strigolactone-dependent branching control 27 . According to the 'second messenger model', strigolactones are transported to the bud as a second messenger of auxin 28 , hence cellular transport of strigolactones in the axillary regions would be indispensable.…”

supporting

confidence: 85%

“…In the 'auxin transport canalization-based model', strigolactones are thought to dampen polar auxin transport, resulting in the accumulation of auxin to levels that inhibit bud outgrowth 29 . Strigolactones could restrict auxin transport systemically and/or locally 27 . For both models, local strigolactone transport capacity near the axils would be in line with the inhibitory role of strigolactones on branching.…”

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confidence: 99%

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A petunia ABC protein controls strigolactone-dependent symbiotic signalling and branching

Kretzschmar

Kohlen

Sasse

et al. 2012

Nature

510

431

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Strigolactones were originally identified as stimulators of the germination of root-parasitic weeds 1 that pose a serious threat to resource-limited agriculture 2 . They are mostly exuded from roots and function as signalling compounds in the initiation of arbuscular mycorrhizae 3 , which are plant-fungus symbionts with a global effect on carbon and phosphate cycling 4 . Recently, strigolactones were established to be phytohormones that regulate plant shoot architecture by inhibiting the outgrowth of axillary buds 5,6 . Despite their importance, it is not known how strigolactones are transported. ATP-binding cassette (ABC) transporters, however, are known to have functions in phytohormone translocation [7][8][9] . Here we show that the Petunia hybrida ABC transporter PDR1 has a key role in regulating the development of arbuscular mycorrhizae and axillary branches, by functioning as a cellular strigolactone exporter. P. hybrida pdr1 mutants are defective in strigolactone exudation from their roots, resulting in reduced symbiotic interactions. Above ground, pdr1 mutants have an enhanced branching phenotype, which is indicative of impaired strigolactone allocation. Overexpression of Petunia axillaris PDR1 in Arabidopsis thaliana results in increased tolerance to high concentrations of a synthetic strigolactone, consistent with increased export of strigolactones from the roots. PDR1 is the first known component in strigolactone transport, providing new opportunities for investigating and manipulating strigolactone-dependent processes.Strigolactones are a new class of carotenoid-derived 10 phytohormone in land plants. In addition to their role in shoot branching, strigolactones are exuded into the rhizosphere under phosphorus-limiting conditions 5 and act as growth stimulants of arbuscular mycorrhizal fungi 3 . To identify efflux carriers of arbuscular-mycorrhiza-promoting factors such as strigolactones, we used a degenerate primer approach ( Supplementary Fig. 2a) to isolate full-size PDR-type transporters (also known as ABC subtype G (ABCG) transporters) of P. hybrida that are abundant in phosphate-starved or mycorrhizal roots. The rationale behind the focus on these transporters, of which there are 15 in Arabidopsis 11 , 23 in Oryza sativa (rice) 11 and 23 putative factors in Solanum lycopersicum (tomato) ( Supplementary Fig. 3a), was that they are plasma membrane proteins often found in roots 12 , they are implicated in below-ground plantmicrobe interactions 13,14 , and they have affinities for compounds that are structurally related to strigolactones 8,9,15 . Of six primary candidates, only P. hybrida PDR1 had increased expression in roots that were subjected to either phosphate starvation (Fig. 1a) or colonization by the arbuscular mycorrhizal fungus Glomus intraradices (Fig. 1b). Furthermore, PDR1 transcript levels increased in response to treatment with the synthetic strigolactone analogue GR24 or the auxin analogue 1-naphthaleneacetic acid (NAA) (Fig. 1c). Auxin has been shown to upregulate strigolactone-bi...

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supporting

confidence: 85%

mentioning

confidence: 99%

A petunia ABC protein controls strigolactone-dependent symbiotic signalling and branching

Kretzschmar

Kohlen

Sasse

et al. 2012

Nature

510

431

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“…The identification of a series of branching mutants in Arabidopsis (Arabidopsis thaliana) known as max (for more axillary growth) and cloning of the MAX genes (Stirnberg et al, 2002;Sorefan et al, 2003;Booker et al, 2004;Booker et al, 2005), as well as related genes from pea (Sorefan et al, 2003;Johnson et al, 2006), rice (Oryza sativa; Ishikawa et al, 2005;Zou et al, 2006;Arite et al, 2007), and petunia (Snowden et al, 2005;Simons et al, 2007) led to the discovery that the SMS signal is a new hormone, strigolactone (Gomez-Roldan et al, 2008;Umehara et al, 2008). Therefore, apical dominance in annuals is regulated by auxin, cytokinin, and strigolactones and their interactions (Beveridge et al, 2009;Domagalska and Leyser, 2011). The involvement of other factors may also be important; for example, the early events of decapitation-induced bud outgrowth in pea are independent of auxin (Morris et al, 2005).…”

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confidence: 99%

Inhibition of Tiller Bud Outgrowth in thetinMutant of Wheat Is Associated with Precocious Internode Development

et al. 2012

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Tillering (branching) is a major yield component and, therefore, a target for improving the yield of crops. However, tillering is regulated by complex interactions of endogenous and environmental signals, and the knowledge required to achieve optimal tiller number through genetic and agronomic means is still lacking. Regulatory mechanisms may be revealed through physiological and molecular characterization of naturally occurring and induced tillering mutants in the major crops. Here we characterize a reduced tillering (tin, for tiller inhibition) mutant of wheat (Triticum aestivum). The reduced tillering in tin is due to early cessation of tiller bud outgrowth during the transition of the shoot apex from the vegetative to the reproductive stage. There was no observed difference in the development of the main stem shoot apex between tin and the wild type. However, tin initiated internode development earlier and, unlike the wild type, the basal internodes in tin were solid rather than hollow. We hypothesize that tin represents a novel type of reduced tillering mutant associated with precocious internode elongation that diverts sucrose (Suc) away from developing tillers. Consistent with this hypothesis, we have observed upregulation of a gene induced by Suc starvation, downregulation of a Suc-inducible gene, and a reduced Suc content in dormant tin buds. The increased expression of the wheat Dormancy-associated (DRM1-like) and Teosinte Branched1 (TB1-like) genes and the reduced expression of cell cycle genes also indicate bud dormancy in tin. These results highlight the significance of Suc in shoot branching and the possibility of optimizing tillering by manipulating the timing of internode elongation.

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“…Furthermore, xylem sap flow carries cytokinins (CKs), a fundamental root-to-shoot link signal (phytohormone) mainly produced in root tips that stimulates the breaking of bud dormancy (Domagalska and Leyser, 2011;Sachs and Thimann, 1967). In addition, CKs supplied by the roots are limited at suboptimal temperatures, while warming may increase their production or concentration in sap, promoting the onset of bud burst (Lyr, 1996) with the anticipation of water sap flow.…”

Section: Soil Temperature and Bud Burstmentioning

confidence: 99%

Effects of soil warming and nitrogen foliar applications on bud burst of black spruce

Barba

Rossi

Deslauriers

et al. 2015

Trees

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The observation of phenological events can be used as biological indicator of environmental changes, especially from the perspective of climate change. In boreal forests, the onset of the bud burst is a key factor in the length of the growing season. With current climate change, the major factors limiting the growth of boreal trees (i.e., temperature and nitrogen availability) are changing and studies on mature trees are limited. The aim of this study was to investigate the effects of soil warming and increased nitrogen ( 3

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Signal integration in the control of shoot branching

Cited by 681 publications

References 100 publications

A petunia ABC protein controls strigolactone-dependent symbiotic signalling and branching

A petunia ABC protein controls strigolactone-dependent symbiotic signalling and branching

Inhibition of Tiller Bud Outgrowth in thetinMutant of Wheat Is Associated with Precocious Internode Development

Effects of soil warming and nitrogen foliar applications on bud burst of black spruce

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