Loss of function of a rice TPR-domain RNA-binding protein confers broad-spectrum disease resistance

Abstract

Crops carrying broad-spectrum resistance loci provide an effective strategy for controlling infectious disease because these loci typically confer resistance to diverse races of a pathogen or even multiple species of pathogens. Despite their importance, only a few crop broad-spectrum resistance loci have been reported. Here, we report the identification and characterization of the rice <i>bsr-k1</i> (broad-spectrum resistance Kitaake-1) mutant, which confers broad-spectrum resistance against <i>Magnaporthe oryzae</i> and <i>Xanthomonas oryzae</i> pv <i>oryzae</i> with no major penalty on key agronomic traits. Map-based cloning reveals that <i>Bsr-k1</i> encodes a tetratricopeptide repeats (TPRs)-containing protein, which binds to mRNAs of multiple <i>OsPAL</i> (<i>OsPAL1-7</i>) genes and promotes their turnover. Loss of function of the <i>Bsr-k1</i> gene leads to accumulation of <i>OsPAL1-7</i> mRNAs in the <i>bsr-k1</i> mutant. Furthermore, overexpression of <i>OsPAL1</i> in wild-type rice TP309 confers resistance to <i>M. oryzae</i>, supporting the role of <i>OsPAL1</i> Our discovery of the <i>bsr-k1</i> allele constitutes a significant conceptual advancement and provides a valuable tool for breeding broad-spectrum resistant rice.