Suppression among alleles

03 October 2014 - By: Christoph Benning

Suppression among alleles encoding nucleotide-binding–leucine-rich repeat resistance proteins interferes with resistance in F1 hybrid and allele-pyramided wheat plants 

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An emasculated spike (left) of a wheat line with a resistance gene is pollinated using a flowering spike (right) of a wheat line carrying a different resistance gene. Hybrid seeds are formed on the ripened spike (centre).


By Christoph Benning


The Plant Journal, Vol 79, pages 893–903, Daniel Stirnweis, Samira D. Milani, Susanne Brunner, Gerhard Herren, Gabriele Buchmann, David Peditto, Tina Jordan, Beat Keller http:// onlinelibrary.wiley.com/doi/10.1111/ tpj.12592/abstract 

Stirnweis et al. describe resistance suppression in the context of hybridization or allele-pyramiding, while at the same time reporting findings on functional and mechanistic aspects.

This phenomenon has previously not been understood or has possibly often been misinterpreted as gene-dosage effects or genetic incompatibility with, for example, signalling components. The findings of this study, together with the results of a companion paper by Hurni et al. (http://onlinelibrary.wiley.com/ doi/10.1111/tpj.12593/abstract), represent molecular evidence for the identity of a suppressor gene - the molecular nature of suppressors has been an open question for the breeding-related community for decades.

The results are highly relevant for applications in breeding and biotechnology, having an impact on the planning of crop-breeding programmes worldwide. That suppression can directly involve alleles of the same resistance gene is of special importance for hybrid breeding. Exploitation of F1 hybrids of important crop species such as rice and wheat has begun and, therefore, these findings will have increased relevance for the future.

With more and more resistance genes, and alleles of them, being cloned, geneand allele-pyramiding approaches have become more feasible, and are now often recommended as ‘the’ most important strategy used in achieving broad-spectrum and durable resistance in crop plants.

As resistance suppression sets limitations on these approaches, the findings from this study may help to avoid or bypass these restrictions. The discovery of mechanistic aspects of resistance suppression may be recognized by the large scientific community working on NB-LRR proteins, as identified suppression effects may help to explain functional aspects of immunity control and activation. 

 
Category: Plant Biology
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Christoph Benning

Christoph is the current Editor-in-Chief of The Plant Journal and the Director of the MSU-DOE Plant Research Laboratory. He has been working for over 20 years on different aspects of lipid metabolism in photosynthetic organisms. Recently, he has applied genomic and genetic approaches to identify key regulatory factors and enzymes required for triacylglycerol biosynthesis and turnover in microalgae.