|YUAN, XINJIE - Huazhong Agricultural University|
|YAN, CHENGHUAN - Huazhong Agricultural University|
|WU, ZHUJUN - Huazhong Agricultural University|
|REN, FEIHONG - Huazhong Agricultural University|
|ZHAN, HUI - Huazhong Agricultural University|
|CHEN, JIONGJIONG - Huazhong Agricultural University|
|KUANG, HANHUI - Huazhong Agricultural University|
Submitted to: Molecular Plant
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/5/2015
Publication Date: 9/8/2015
Publication URL: http://dx.doi..org/10.1016/j.molp.2015.09.001
Citation: Yuan, X., Yan, C., Wu, Z., Ren, F., Zhan, H., Baker, B.J., Chen, J., Kuang, H. 2015. Frequent gain and loss of resistance against tobacco mosaic virus (TMV) in Nicotiana Species. Molecular Plant. 8(12):1813-1815. doi: 10.1016/j.molp.2015.09.001.
Interpretive Summary: A major line of defense against devastating pathogen disease requires ongoing identification and breeding of new resistance (R)-genes from wild species into crops. Plant R-genes encode innate immune receptors, which specifically recognize pathogen effectors and induce rapid and effective disease resistance responses. R-genes form one of the most prevalent and diverse classes of plant genes and this effective defense system depends on generating new R-genes with novel resistance functions to meet challenge to defend against rapidly evolving pathogens. Continual updates to the plant’s genetic arsenal occur through ongoing amplification, diversification and positive selection through co-evolution with pathogens. Evolutionary processes that To understand R-gene origins and evolution we used cloning and functional analysis to determine the evolutionary processes generating active resistance. We compared evolution of two distinct R-gene families for TMV resistance, N and N’. Our results indicate that N and N’-mediated TMV resistance has been frequently gained and lost in Nicotiana. Our data provide insights into the origin and evolution of functional resistance genes in wild species. The information from this study will help to develop strategies to pinpoint and deploy active R-genes for breeding and crop protection.
Technical Abstract: Resistance (R) genes represent one of the most divergent gene families in plants. Novel resistance function might arise through point mutations or sequence exchanges between paralogues. Sequence exchanges between homologues may generate a large number of distinct genes. In fact, some R gene families are extensive chimeras, contributing considerable resistance diversity for a species. In contrast, other R gene families are highly conserved between different genotypes. Distantly related plant species may contain resistance against the same pathogen. Such ‘‘conserved’’ resistance in different species might be inherited from their common ancestor or result from convergent evolution. How frequently convergent evolution has occurred in nature and its underlying mechanism remain poorly understood. We screened different Nicotiana species using tobacco mosaic virus (TMV), and the origin and evolution of TMV resistance were studied in detail.