Abstract
BackgroundThree NBS-LRR genes, Rpi-blb2, Mi-1.2, and Cami, constitute a very special plant resistance gene family. These genes confer resistance against 4 distantly related pathogen species in 3 different Solanaceae hosts. To characterize this noted resistance, we conducted a series of studies on this gene family.ResultsFirst, homologs of this gene family were identified in the pepper, tomato and potato genomes. This revealed a large variation in copy number within this gene family among species and a great divergence was found both between and within species. To gain more information pertaining to gene resistance within this family, 121 LRR regions were cloned in 16 different wild/cultivated potato accessions. Again, frequent copy number variations and a high level of divergence between homolog were observed common among accessions. The divergence within species was so high that it reaches the level of divergence between species. Also, frequent frameshift mutations and abundant gene conversion events were identified in these LRR regions.ConclusionsOur findings suggest that this family harbors an unusually high level of genetic abundance, making it of particular interest. Together with other reported examples, our study also provides evidence that multi-resistance is a common trait in R gene families like this.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-015-0493-z) contains supplementary material, which is available to authorized users.
Highlights
Three nucleotide-binding sites and leucine-rich repeat (NBS-LRR) genes, Rpi-blb2, Mi-1.2, and Cami, constitute a very special plant resistance gene family
The re-annotated Number of homologs π π (NBS)-LRR gene sets of potato and tomato were downloaded from previous studies [19, 20]
To identify the homologs of Rpi-blb2/Mi-1.2/Cami, the coding sequence (CDS) of these 3 genes were used as query and BLAST against the whole-genome CDSs of the 3 genomes and 2 re-annotated gene sets
Summary
Three NBS-LRR genes, Rpi-blb, Mi-1.2, and Cami, constitute a very special plant resistance gene family. These genes confer resistance against 4 distantly related pathogen species in 3 different Solanaceae hosts. To characterize this noted resistance, we conducted a series of studies on this gene family. The potato, along with the tomato and pepper, are members of Solanaceae family, with the potato being one of the world’s most important food crops [1]. Late blight disease is responsible for the European potato famine in the 19th century which almost completely destroyed potato crops and led to the starvation of millions of people [4]. The control of such plant diseases is of fundamental importance
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