At the crossroads: strigolactones mediate changes in cytokinin synthesis and signalling in response to nitrogen limitation

A - Papers appearing in refereed journals

Sigalas, P., Bennett, T., Buchner, P. H., Thomas, S. G., Jamois, F., Arkoun, M., Yvin, J.-C., Bennett, M.J. and Hawkesford, M. J. 2024. At the crossroads: strigolactones mediate changes in cytokinin synthesis and signalling in response to nitrogen limitation. The Plant Journal. https://doi.org/10.1111/tpj.16976

AuthorsSigalas, P., Bennett, T., Buchner, P. H., Thomas, S. G., Jamois, F., Arkoun, M., Yvin, J.-C., Bennett, M.J. and Hawkesford, M. J.
Abstract

Strigolactones (SLs) are key regulators of shoot growth and responses to environmental stimuli. Numerous studies have indicated that nitrogen (N) limitation induces SL biosynthesis, suggesting that SLs may play a pivotal role in coordinating systemic responses to N availability, but this idea has not been clearly demonstrated. Here, we generated triple knockout mutants in the SL synthesis gene TaDWARF17 (TaD17) in bread wheat and investigated their phenotypic and transcriptional responses under N limitation, aiming to elucidate the role of SLs in the adaptation to N limitation. Tad17 mutants display typical SL mutant phenotypes, and fail to adapt their shoot growth appropriately to N. Despite exhibiting an increased tillering phenotype, Tad17 mutants continued to respond to N limitation by reducing tiller number, suggesting that SLs are not the sole regulators of tillering in response to N availability. RNA-seq analysis of basal nodes revealed that the loss of D17 significantly altered the transcriptional response of N-responsive genes, including changes in the expression profiles of key N response master regulators. Crucially, our findings suggest that SLs are required for the transcriptional downregulation of cytokinin (CK) synthesis and signalling in response to N limitation. Collectively, our results suggest that SLs are essential for the appropriate morphological and transcriptional adaptation to N limitation in wheat, and that the repressive effect of SLs on shoot growth is partly mediated by their repression of CK synthesis.

KeywordsStrigolactones; Cytokinin; Nitrogen; RNA-seq; Wheat; Triticum aestivum; Tillering
Year of Publication2024
JournalThe Plant Journal
Digital Object Identifier (DOI)https://doi.org/10.1111/tpj.16976
Open accessPublished as ‘gold’ (paid) open access
FunderBiotechnology and Biological Sciences Research Council
Agro Innovation International
Funder project or codeDesigning Future Wheat - WP1 - Increased efficiency and sustainability
Delivering Sustainable Wheat (WP1): Targeted Sustainability-Trait Discovery
Genetic variation and chemical control of tillering in wheat
Publisher's version
Output statusPublished
Publication dates
Online13 Aug 2024
Publication process dates
Accepted01 Aug 2024
PublisherWiley
ISSN0960-7412

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