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Open Access Research article

Plant disease resistance is augmented in uzu barley lines modified in the brassinosteroid receptor BRI1

Shahin S Ali14*, Lokanadha R Gunupuru1, G B Sunil Kumar1, Mojibur Khan15, Steve Scofield2, Paul Nicholson3 and Fiona M Doohan1

Author Affiliations

1 Molecular Plant-Microbe Interactions Laboratory, School of Biology and Environmental Science, University College Dublin, Dublin 4, Ireland

2 Department of Agronomy, USDA-ARS, Crop Production and Pest Control Research Unit and Purdue University, West Lafayette 47907, IN, USA

3 Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK

4 SPCL, USDA/ARS Beltsville Agricultural Research Center, Beltsville 20705, MD, USA

5 Present address: Institute of Advanced Study in Science and Technology, Guwahati -35, India

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BMC Plant Biology 2014, 14:227  doi:10.1186/s12870-014-0227-1

Published: 20 August 2014

Abstract

Background

Brassinosteroid hormones regulate many aspects of plant growth and development. The membrane receptor BRI1 is a central player in the brassinosteroid signaling cascade. Semi-dwarf ‘uzu’ barley carries a mutation in a conserved domain of the kinase tail of BRI1 and this mutant allele is recognised for its positive contribution to both yield and lodging resistance.

Results

Here we show that uzu barley exhibits enhanced resistance to a range of pathogens. It was due to a combination of preformed, inducible and constitutive defence responses, as determined by a combination of transcriptomic and biochemical studies. Gene expression studies were used to determine that the uzu derivatives are attenuated in downstream brassinosteroid signaling. The reduction of BRI1 RNA levels via virus-induced gene silencing compromised uzu disease resistance.

Conclusions

The pathogen resistance of uzu derivatives may be due to pleiotropic effects of BRI1 or the cascade effects of their repressed BR signaling.

Keywords:
Disease resistance; Brassinosteroid; Uzu; BRI1; Fusarium