LATERAL BRANCHING OXIDOREDUCTASE specificity for strigolactone branching inhibition in barley

Maiko Inoue; Apriadi Situmorang; Jack H Kelly; Weiwei Chen; Hui Zhu; Carlotta C Ferrario; Veronica Gregis; Alessandro Vajani; Salar Shaaf; Abhisek Biswas; Rana Alqusumi; Mark T Waters; Matthew R Tucker; Dabing Zhang; Stephanie J Watts-Williams; Agnieszka Janiak; Marek Marzec; Beata Chmielewska; Laura Rossini; Kaori Yoneyama; Philip B Brewer

doi:10.1093/jxb/eraf285

LATERAL BRANCHING OXIDOREDUCTASE specificity for strigolactone branching inhibition in barley

J Exp Bot. 2025 Nov 5;76(18):5367-5381. doi: 10.1093/jxb/eraf285.

Authors

Maiko Inoue¹, Apriadi Situmorang², Jack H Kelly², Weiwei Chen², Hui Zhu², Carlotta C Ferrario^{3

4}, Veronica Gregis³, Alessandro Vajani⁴, Salar Shaaf^{4

5}, Abhisek Biswas⁴, Rana Alqusumi⁶, Mark T Waters⁶, Matthew R Tucker^{2

7

8}, Dabing Zhang^{2

7}, Stephanie J Watts-Williams^{2

8}, Agnieszka Janiak⁹, Marek Marzec⁹, Beata Chmielewska⁹, Laura Rossini⁴, Kaori Yoneyama¹, Philip B Brewer^{2

8

10

11}

Affiliations

¹ Department of Biochemistry and Molecular Biology, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama 338-8570, Japan.
² Waite Research Institute, School of Agriculture Food & Wine, The University of Adelaide, Adelaide, SA 5064, Australia.
³ Department of Biosciences, University of Milan, Via Celoria 26, Milan 20133, Italy.
⁴ Department of Agricultural and Environmental Sciences (DiSAA), University of Milan, Via Celoria 2, Milan 20133, Italy.
⁵ Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, D-06466 Seeland, Germany.
⁶ School of Molecular Sciences, The University of Western Australia, Perth, WA 6009, Australia.
⁷ ARC Training Centre for Future Crops Development, The University of Adelaide, Adelaide, SA 5064, Australia.
⁸ Australian Research Council Centre of Excellence in Plants for Space, The University of Adelaide, Adelaide, SA 5064, Australia.
⁹ Institute of Biology, Biotechnology and Environmental Protection, University of Silesia in Katowice, Jagiellonska 28, Katowice 40032, Poland.
¹⁰ Institute for Future Farming Systems, Central Queensland University, Rockhampton, QLD 4701, Australia.
¹¹ La Trobe Institute for Sustainable Agriculture and Food, La Trobe University, Bundoora, VIC 3086, Australia.

Abstract

Strigolactone (SL) mutants display a range of phenotypes, such as increased branching, reduced stature, and a loss of SLs exuded from roots into the soil. SL biosynthesis is complex and divergent between plant species. Recently, mutants defective in specific SL biosynthesis genes have shown a loss of exuded SLs, but no obvious change in branching (tillering). This means that functional specification may exist between certain SL subtypes. It has been suggested that the LATERAL BRANCHING OXIDOREDUCTASE (LBO) enzyme acts in a subpathway of SLs that is specific for branching. Here we report that barley plants mutant in hvlbo have increased tillering, but normal production of SLs detected in roots and root exudates. This finding supports the idea that SLs have functional or tissue-specific differences and that the LBO pathway has specificity for bud outgrowth rather than exudates.

Keywords: Barley; biosynthesis; branching; crop; root exudate; strigolactone; tillering; yield.

Abstract

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