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The plasticity of NBS resistance genes in sorghum is driven by multiple evolutionary processes

Mace, Emma and Tai, Shuaishuai and Innes, David and Godwin, Ian and Hu, Wushu and Campbell, Bradley and Gilding, Edward and Cruickshank, Alan and Prentis, Peter and Wang, Jun and Jordan, David (2014) The plasticity of NBS resistance genes in sorghum is driven by multiple evolutionary processes. BMC Plant Biology, 14 (1). p. 253. ISSN 1471-2229

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Article Link(s): http://dx.doi.org/10.1186/s12870-014-0253-z

Publisher URL: http://www.biomedcentral.com/1471-2229/14/253/

Abstract

Background
Increased disease resistance is a key target of cereal breeding programs, with disease outbreaks continuing to threaten global food production, particularly in Africa. Of the disease resistance gene families, the nucleotide-binding site plus leucine-rich repeat (NBS-LRR) family is the most prevalent and ancient and is also one of the largest gene families known in plants. The sequence diversity in NBS-encoding genes was explored in sorghum, a critical food staple in Africa, with comparisons to rice and maize and with comparisons to fungal pathogen resistance QTL.

Results
In sorghum, NBS-encoding genes had significantly higher diversity in comparison to non NBS-encoding genes and were significantly enriched in regions of the genome under purifying and balancing selection, both through domestication and improvement. Ancestral genes, pre-dating species divergence, were more abundant in regions with signatures of selection than in regions not under selection. Sorghum NBS-encoding genes were also significantly enriched in the regions of the genome containing fungal pathogen disease resistance QTL; with the diversity of the NBS-encoding genes influenced by the type of co-locating biotic stress resistance QTL.

Conclusions
NBS-encoding genes are under strong selection pressure in sorghum, through the contrasting evolutionary processes of purifying and balancing selection. Such contrasting evolutionary processes have impacted ancestral genes more than species-specific genes. Fungal disease resistance hot-spots in the genome, with resistance against multiple pathogens, provides further insight into the mechanisms that cereals use in the “arms race” with rapidly evolving pathogens in addition to providing plant breeders with selection targets for fast-tracking the development of high performing varieties with more durable pathogen resistance.

Item Type:Article
Business groups:Crop and Food Science
Keywords:Cereals; Disease resistance; Domestication; Maize; NBS-LRR genes; QTL; Rice; Selection; Sorghum
Subjects:Plant pests and diseases > Pest control and treatment of diseases. Plant protection
Science > Biology > Genetics > Quantitative genetics (esp. Quantitative Trait Loci (QTL) articles)
Plant pests and diseases > Individual or types of plants or trees > Sorghum
Science > Botany > Genetics
Plant culture > Field crops > Sorghum
Deposited On:21 Oct 2014 23:02
Last Modified:08 Jun 2015 16:02

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