Lr67 and Lr34 rust resistance genes have much in common – they confer broad spectrum resistance to multiple pathogens in wheat

Wolfgang Spielmeyer,Michael Ayliffe,Colin Wellings,Rohit Mago

doi:10.1186/1471-2229-13-96

Wolfgang Spielmeyer, Michael Ayliffe + Show 2 more

Open Access

https://doi.org/10.1186/1471-2229-13-96

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Abstract

BackgroundAdult plant rust resistance genes Lr67 and Lr34 confer race non-specific resistance to multiple fungal pathogens of wheat. Induced, susceptible mutants were characterised for both genes.ResultsThree categories of Lr34 mutants were identified that were either partial susceptible, fully susceptible or hyper-susceptible to stripe rust and leaf rust. The likely impact of the mutational change on the predicted Lr34 protein correlated with differences in response to rust infection. Four independent Lr67 mutants were recovered that were susceptible to stripe rust, leaf rust and stem rust pathogens, including one possible hyper-susceptible Lr67 mutant.ConclusionsDetailed study of Lr34 mutants revealed that subtle changes in resistance response to multiple pathogens were correlated with mutational changes in the predicted protein. Recovery of independent Lr67 mutants indicates that as for Lr34, a single gene at the Lr67 locus is likely to confer resistance to multiple pathogens. The infection phenotypes of Lr67 mutants closely resembled that of Lr34 mutants.

Highlights

Adult plant rust resistance genes Lr67 and Lr34 confer race non-specific resistance to multiple fungal pathogens of wheat
The most widely deployed and best characterised of these genes, Lr34, confers durable, adult plant resistance (APR) to leaf rust caused by Puccinia triticina, stripe rust caused by Puccinia striiformis f.sp. tritici and powdery mildew caused by Blumeria graminis [2,3,4,5]
Characterisation of Lr34 mutant phenotypes Six sodium azide induced Lr34 mutants (2B, 2F, 2G, 3E, 4C, 4E) were previously reported that were susceptible to leaf rust, stripe rust and stem rust [15]

Summary

Introduction

Adult plant rust resistance genes Lr67 and Lr34 confer race non-specific resistance to multiple fungal pathogens of wheat. Many rust resistance genes are known in wheat but only a few provide durable, race non-specific resistance to multiple pathogens [1]. Lr67 was described which has similar characteristics to Lr34 in that it confers leaf tip necrosis and provides partial, broad spectrum, adult plant resistance to leaf rust and stripe rust [7,8]. Based on this phenotypic similarity Lr67 is predicted to provide durable rust resistance, this remains inconclusive as the gene. Further studies demonstrated that unlinked genetic loci interacted with Lr34 to enable the expression of stem rust resistance in Thatcher and Thatcher derivatives [11,12,13,14]

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