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Strigolactone biosynthesis is evolutionarily conserved, regulated by phosphate starvation and contributes to resistance against phytopathogenic fungi in a moss, Physcomitrella patens
Author(s) -
Decker Eva L.,
Alder Adrian,
Hunn Stefan,
Ferguson Jenny,
Lehtonen Mikko T.,
Scheler Bjoern,
Kerres Klaus L.,
Wiedemann Gertrud,
SafaviRizi Vajiheh,
Nordzieke Steffen,
Balakrishna Aparna,
Baz Lina,
Avalos Javier,
Valkonen Jari P. T.,
Reski Ralf,
AlBabili Salim
Publication year - 2017
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.14506
Subject(s) - physcomitrella patens , biology , strigolactone , arabidopsis , biosynthesis , mutant , biochemistry , enzyme , marchantia polymorpha , botany , gene
Summary In seed plants, strigolactones ( SL s) regulate architecture and induce mycorrhizal symbiosis in response to environmental cues. SL s are formed by combined activity of the carotenoid cleavage dioxygenases ( CCD s) 7 and 8 from 9‐ cis ‐β‐carotene, leading to carlactone that is converted by cytochromes P450 (clade 711; MAX 1 in Arabidopsis ) into various SL s. As Physcomitrella patens possesses CCD 7 and CCD 8 homologs but lacks MAX 1 , we investigated if Pp CCD 7 together with Pp CCD 8 form carlactone and how deletion of these enzymes influences growth and interactions with the environment. We investigated the enzymatic activity of Pp CCD 7 and Pp CCD 8 in vitro , identified the formed products by high performance liquid chromatography ( HPLC ) and LC ‐ MS , and generated and analysed Δ CCD 7 and Δ CCD 8 mutants. We defined enzymatic activity of Pp CCD 7 as a stereospecific 9‐ cis ‐ CCD and Pp CCD 8 as a carlactone synthase. Δ CCD 7 and Δ CCD 8 lines showed enhanced caulonema growth, which was revertible by adding the SL analogue GR 24 or carlactone. Wild‐type ( WT ) exudates induced seed germination in Orobanche ramosa . This activity was increased upon phosphate starvation and abolished in exudates of both mutants. Furthermore, both mutants showed increased susceptibility to phytopathogenic fungi. Our study reveals the deep evolutionary conservation of SL biosynthesis, SL function, and its regulation by biotic and abiotic cues.