Format

Send to

Choose Destination
See comment in PubMed Commons below
Proc Natl Acad Sci U S A. 2013 Nov 12;110(46):18572-7. doi: 10.1073/pnas.1318211110. Epub 2013 Oct 21.

Rapidly evolving R genes in diverse grass species confer resistance to rice blast disease.

Author information

  • 1State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093, China.

Abstract

We show that the genomes of maize, sorghum, and brachypodium contain genes that, when transformed into rice, confer resistance to rice blast disease. The genes are resistance genes (R genes) that encode proteins with nucleotide-binding site (NBS) and leucine-rich repeat (LRR) domains (NBS-LRR proteins). By using criteria associated with rapid molecular evolution, we identified three rapidly evolving R-gene families in these species as well as in rice, and transformed a randomly chosen subset of these genes into rice strains known to be sensitive to rice blast disease caused by the fungus Magnaporthe oryzae. The transformed strains were then tested for sensitivity or resistance to 12 diverse strains of M. oryzae. A total of 15 functional blast R genes were identified among 60 NBS-LRR genes cloned from maize, sorghum, and brachypodium; and 13 blast R genes were obtained from 20 NBS-LRR paralogs in rice. These results show that abundant blast R genes occur not only within species but also among species, and that the R genes in the same rapidly evolving gene family can exhibit an effector response that confers resistance to rapidly evolving fungal pathogens. Neither conventional evolutionary conservation nor conventional evolutionary convergence supplies a satisfactory explanation of our findings. We suggest a unique mechanism termed "constrained divergence," in which R genes and pathogen effectors can follow only limited evolutionary pathways to increase fitness. Our results open avenues for R-gene identification that will help to elucidate R-gene vs. effector mechanisms and may yield new sources of durable pathogen resistance.

PMID:
24145399
PMCID:
PMC3831948
DOI:
10.1073/pnas.1318211110
[PubMed - indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Support Center