Highly Branched Phenotype of the Petunia dad1-1 Mutant Is Reversed by Grafting

Napoli, Carolyn A.

doi:10.1104/pp.111.1.27

Cited by 165 publications

(169 citation statements)

References 8 publications

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“…This phenotype has been observed in stem cuttings of pea (Fig. 2) (Rasmussen et al 2012) and tomato ) and etiolated hypocotyls of Arabidopsis (Rasmussen et al 2012) and as well as in lower stems of intact petunia lacking endogenous strigolactones (Napoli 1996). Exogenous strigolactone treatments inhibited adventitious rooting in a MAX2/RMS4-dependent manner Rasmussen et al 2012) and biosynthesis mutants from pea (rms5) but not from Arabidopsis (max4) were more sensitive to exogenous GR24 application than the wild type (Rasmussen et al 2012).…”

Section: Strigolactones Inhibit Adventitious Root Formationmentioning

confidence: 70%

Strigolactones fine-tune the root system

Rasmussen

Depuydt

Goormachtig

et al. 2013

Planta

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Strigolactones were originally discovered to be involved in parasitic weed germination, in mycorrhizal association and in the control of shoot architecture. Despite their clear role in rhizosphere signaling, comparatively less attention has been given to the belowground function of strigolactones on plant development. However, research has revealed that strigolactones play a key role in the regulation of the root system including adventitious roots, primary root length, lateral roots, root hairs and nodulation. Here, we review the recent progress regarding strigolactone regulation of the root system and the antagonism and interplay with other hormones

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Section: Strigolactones Inhibit Adventitious Root Formationmentioning

confidence: 70%

Strigolactones fine-tune the root system

Rasmussen

Depuydt

Goormachtig

et al. 2013

Planta

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“…Dad1 mutants initiate branches from all nodes ( Supplementary Fig. 8d), and although branch elongation is retarded compared with the wild type, these mutants eventually produce full branches from every node 20,30 . At flowering time, this results in a phenotype that is more pronounced than in any of the pdr1 mutants, which have final branch patterns that differ only marginally from the respective wild-type plants ( Supplementary Fig.…”

mentioning

confidence: 99%

“…The mild branching phenotype of pdr1 mutants relative to the strigolactone-biosynthesis mutant dad1 (ref. 30) suggests that residual transport and/or locally produced strigolactones may compensate for defective strigolactone transport in the shoot. However, arbuscular mycorrhizal development was affected to a similar degree in the pdr1 and dad1 mutants, revealing that below-ground strigolactone transport and secretion relies primarily on PDR1.…”

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confidence: 99%

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

Kretzschmar

Kohlen

Sasse

et al. 2012

Nature

482

417

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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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“…Paradoxically, the mutants were found to have generally higher levels of auxin and lower levels of xylem cytokinin, facts difficult to reconcile with ideas about the roles of auxin and cytokinin in regulating bud outgrowth (Beveridge et al, 1997). These mutants were ramosus (rms) in pea (Pisum sativum), decreased apical dominance (dad) in petunia (Petunia hybrida), more axillary growth (max) in Arabidopsis (Arabidopsis thaliana), and particular dwarf (d) mutants in rice (Oryza sativa; Beveridge et al, 1994;Napoli, 1996;Stirnberg et al, 2002;Ishikawa et al, 2005). Grafting studies demonstrated that increased bud outgrowth in some of the mutants was caused by the loss of a long-distance mobile signal (termed SMS; Beveridge, 2006) that moved upward from lower tissues (Beveridge et al, 1994;Napoli, 1996;Foo et al, 2001;Turnbull et al, 2002).…”

mentioning

confidence: 99%

“…These mutants were ramosus (rms) in pea (Pisum sativum), decreased apical dominance (dad) in petunia (Petunia hybrida), more axillary growth (max) in Arabidopsis (Arabidopsis thaliana), and particular dwarf (d) mutants in rice (Oryza sativa; Beveridge et al, 1994;Napoli, 1996;Stirnberg et al, 2002;Ishikawa et al, 2005). Grafting studies demonstrated that increased bud outgrowth in some of the mutants was caused by the loss of a long-distance mobile signal (termed SMS; Beveridge, 2006) that moved upward from lower tissues (Beveridge et al, 1994;Napoli, 1996;Foo et al, 2001;Turnbull et al, 2002). Mutant phenotypes were rescued by grafting with wild-type tissue, even in interstock grafts where small pieces of wild-type stem tissue were grafted between mutant rootstock and shoot tissue (Napoli, 1996;Foo et al, 2001).…”

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confidence: 99%

Strigolactone Acts Downstream of Auxin to Regulate Bud Outgrowth in Pea and Arabidopsis

et al. 2009

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During the last century, two key hypotheses have been proposed to explain apical dominance in plants: auxin promotes the production of a second messenger that moves up into buds to repress their outgrowth, and auxin saturation in the stem inhibits auxin transport from buds, thereby inhibiting bud outgrowth. The recent discovery of strigolactone as the novel shootbranching inhibitor allowed us to test its mode of action in relation to these hypotheses. We found that exogenously applied strigolactone inhibited bud outgrowth in pea (Pisum sativum) even when auxin was depleted after decapitation. We also found that strigolactone application reduced branching in Arabidopsis (Arabidopsis thaliana) auxin response mutants, suggesting that auxin may act through strigolactones to facilitate apical dominance. Moreover, strigolactone application to tiny buds of mutant or decapitated pea plants rapidly stopped outgrowth, in contrast to applying N-1-naphthylphthalamic acid (NPA), an auxin transport inhibitor, which significantly slowed growth only after several days. Whereas strigolactone or NPA applied to growing buds reduced bud length, only NPA blocked auxin transport in the bud. Wild-type and strigolactone biosynthesis mutant pea and Arabidopsis shoots were capable of instantly transporting additional amounts of auxin in excess of endogenous levels, contrary to predictions of auxin transport models. These data suggest that strigolactone does not act primarily by affecting auxin transport from buds. Rather, the primary repressor of bud outgrowth appears to be the auxindependent production of strigolactones.

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Highly Branched Phenotype of the Petunia dad1-1 Mutant Is Reversed by Grafting

Cited by 165 publications

References 8 publications

Strigolactones fine-tune the root system

Strigolactones fine-tune the root system

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

Strigolactone Acts Downstream of Auxin to Regulate Bud Outgrowth in Pea and Arabidopsis

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