A phenylpropanoid diglyceride associates with the leaf rust resistance Lr34res gene in wheat

Nandhakishore Rajagopalan; Yuping Lu; Ian W Burton; Fanny Monteil-Rivera; Annamaria Halasz; Elsa Reimer; Rebecca Tweidt; Anita Brûlé-Babel; Hadley R Kutcher; Frank M You; Sylvie Cloutier; Miroslava Cuperlovic-Culf; Colin W Hiebert; Brent D McCallum; Michele C Loewen

doi:10.1016/j.phytochem.2020.112456

A phenylpropanoid diglyceride associates with the leaf rust resistance Lr34res gene in wheat

Phytochemistry. 2020 Oct:178:112456. doi: 10.1016/j.phytochem.2020.112456. Epub 2020 Jul 17.

Authors

Affiliations

¹ National Research Council of Canada, Aquatic and Crop Resources Development Research Center, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada.
² National Research Council of Canada, Aquatic and Crop Resources Development Research Center, 1411 Oxford St., Halifax, NS, B3H 3Z1, Canada.
³ National Research Council of Canada, Aquatic and Crop Resources Development Research Center, 6100 Royalmount Avenue, Montreal, QC, H4P 2R2, Canada.
⁴ National Research Council of Canada, Energy Mining and Environment Research Center, 6100 Royalmount Avenue, Montreal, QC, H4P 2R2, Canada.
⁵ Agriculture and Agri-Food Canada, Morden Research and Development Center, 101 Route 100, Unit 100, Morden, Manitoba, R6M 1Y5, Canada.
⁶ Department of Plant Sciences and the Crop Development Center, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK, S7N 5A8, Canada.
⁷ Department of Plant Science, University of Manitoba, 66 Dafoe Rd. Winnipeg, MB, R3T 2N2, Canada.
⁸ Agriculture and Agri-Food Canada, Ottawa Research and Development Centre, 960 Carling Avenue, Ottawa, ON, K1A 0C6, Canada.
⁹ National Research Council of Canada, Digital Technologies Research Center, 1200 Montreal Road, Ottawa, ON, K1A 0R6, Canada.
¹⁰ National Research Council of Canada, Aquatic and Crop Resources Development Research Center, 100 Sussex Drive, Ottawa, ON, K1A 5A2, Canada. Electronic address: michele.loewen@nrc.ca.

PMID: 32692663
DOI: 10.1016/j.phytochem.2020.112456

Abstract

The gene Lr34res is one of the most long-lasting sources of quantitative fungal resistance in wheat. It is shown to be effective against leaf, stem, and stripe rusts, as well as powdery mildew and spot blotch. Recent biochemical characterizations of the encoded ABC transporter have outlined a number of allocrites, including phospholipids and abscisic acid, consistent with the established general promiscuity of ABC transporters, but ultimately leaving its mechanism of rust resistance unclear. Working with flag leaves of Triticum aestivum L. variety 'Thatcher' (Tc) and a near-isogenic line of 'Thatcher' into which the Lr34res allele was introgressed (Tc+Lr34res; RL6058), a comparative semi-targeted metabolomics analysis of flavonoid-rich extracts revealed virtually identical profiles with the exception of one metabolite accumulating in Tc+Lr34res, which was not present at comparable levels in Tc. Structural characterization of the purified metabolite revealed a phenylpropanoid diglyceride structure, 1-O-p-coumaroyl-3-O-feruloylglycerol (CFG). Additional profiling of CFG across a collection of near-isogenic lines and representative Lr34 haplotypes highlighted a broad association between the presence of Lr34res and elevated accumulations of CFG. Depletion of CFG upon infection, juxtaposed to its relatively lower anti-fungal activity, suggests CFG may serve as a storage form of the more potent anti-microbial hydroxycinnamic acids that are accessed during defense responses. Altogether these findings suggest a role for the encoded LR34res ABC transporter in modifying the accumulation of CFG, leading to increased accumulation of anti-fungal metabolites, essentially priming the wheat plant for defense.

Keywords: Fusarium head blight; Lr34; Phenylpropanoid diglyceride; Poaceae; Semi-targeted metabolomics; Triticum aestivum L..

MeSH terms

Ascomycota*
Basidiomycota*
Diglycerides
Disease Resistance
Plant Diseases
Triticum

Substances

Diglycerides