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

• Published in: Nature (London) Vol. 483; no. 7389; pp. 341 - 344
• Main Authors: Kretzschmar, Tobias, Kohlen, Wouter, Sasse, Joelle, Borghi, Lorenzo, Schlegel, Markus, Bachelier, Julien B., Reinhardt, Didier, Bours, Ralph, Bouwmeester, Harro J., Martinoia, Enrico
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 15.03.2012; Nature Publishing Group
• Subjects: 631/449/2675; 631/45/612/1237; Abscisic Acid - pharmacology; abscisic-acid; Agronomy. Soil science and plant productions; arabidopsis; Arabidopsis - drug effects; Arabidopsis - embryology; Arabidopsis - genetics; Arabidopsis - metabolism; arbuscular-mycorrhizal fungi; ATP-Binding Cassette Transporters - genetics; ATP-Binding Cassette Transporters - metabolism; auxin transport; Biological and medical sciences; Biosynthesis; Economic plant physiology; Flowers & plants; Fundamental and applied biological sciences. Psychology; Fungi; Gene Expression Regulation, Plant; gene family; Genes; Genetic aspects; Genotype & phenotype; Germination; Humanities and Social Sciences; inhibition; Lactones - pharmacology; letter; medicago-truncatula; Microbiology; Molecular Sequence Data; multidisciplinary; Mycorrhizae - drug effects; Naphthaleneacetic Acids - pharmacology; pathway; pcr; Petunia; Petunia - genetics; Petunia - metabolism; Phenotype; Phenotypes; Physiological aspects; Plant Growth Regulators - pharmacology; Plant hormones; Plant proteins; Plant Proteins - genetics; Plant Proteins - metabolism; Plant Roots - drug effects; Plant Roots - metabolism; Plant Roots - microbiology; Roots; Science; Science (multidisciplinary); Signal Transduction - drug effects; Symbiosis; Symbiosis (nodules, symbiotic nitrogen fixation, mycorrhiza...); Symbiosis - drug effects; Translocation; Switzerland; Petunia hybrida; Axillary bud; Arabidopsis thaliana; Fungi; Fungus; Molecular signal; Cruciferae; Dicotyledones; Angiospermae; Export; Solanaceae; Inhibition; Transmembrane protein; Branching; Symbiosis; Root; Symbiont; Plant architecture; Endomycorrhiza; Mycorrhiza; Flower crop; Strigolactones; Herbaceous plant; Spermatophyta; Exudation; Phytohormone; Experimental plant; ABC transporter
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/nature10873

The Petunia hybrida ABC transporter PDR1 functions in strigolactone export from the roots and is important for regulating symbiosis and axillary branch development. Phytohormone transporter identified The strigolactones are plant hormones that regulate shoot branching; they are required for the establishment of widespread plant–fungus symbionts known as mycorrhizae. Here, Kretzschmar et al . report the discovery of a strigolactone transporter protein. The ABC transporter PDR1 from Petunia hybrida is required for the regulation of shoot branching, mycorrhization and interactions with parasitic weeds. 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.