A novel Pik allele confers extended resistance to rice blast

Zhongqiang Qi, Xiuli Meng, Ming Xu, Yan Du, Junjie Yu, Tianqiao Song, Xiayan Pan, Rongsheng Zhang, Huijuan Cao, Mina Yu, Mary Jeanie Telebanco-Yanoria, Guodong Lu, Bo Zhou, Yongfeng Liu

Plant Cell Environ.; 2024 Dec; 47(12):4800-4814. doi: 10.1111/pce.15072.

Abstract

In the ongoing arms race between rice and Magnaporthe oryzae, the pathogen employs effectors to evade the immune response, while the host develops resistance genes to recognise these effectors and confer resistance. In this study, we identified a novel Pik allele, Pik-W25, from wild rice WR25 through bulked-segregant analysis, creating the Pik-W25 NIL (Near-isogenic Lines) named G9. Pik-W25 conferred resistance to isolates expressing AvrPik-C/D/E alleles. CRISPR-Cas9 editing was used to generate transgenic lines with a loss of function in Pik-W25-1 and Pik-W25-2, resulting in loss of resistance in G9 to isolates expressing the three alleles, confirming that Pik-W25-induced immunity required both Pik-W25-1 and Pik-W25-2. Yeast two-hybrid (Y₂H) and split luciferase complementation assays showed interactions between Pik-W25-1 and the three alleles, while Pik-W25-2 could not interact with AvrPik-C, -D, and -E alleles with Y₂H assay, indicating Pik-W25-1 acts as an adaptor and Pik-W25-2 transduces the signal to trigger resistance. The Pik-W25 NIL exhibited enhanced field resistance to leaf and panicle blast without significant changes in morphology or development compared to the parent variety CO39, suggesting its potential for resistance breeding. These findings advance our knowledge of rice blast resistance mechanisms and offer valuable resources for effective and sustainable control strategies.

See https://pubmed.ncbi.nlm.nih.gov/39087779/

Figure: Wei et al. (2019)

Location of the Pi-kf2(t) locus conferring rice blast resistance. a Molecular marker linkage map of rice chromosome 6. The short arm of the chromosome is at the top. The map distances (centimorgan, cM) and marker names are given to the right of the chromosome. Black and red rectangles indicate the approximate positions of centromere (CEN) and Pi-kf2(t) locus, respectively. b Fine genetic linkage map of the rice blast-resistance gene Pi-kf2(t) on chromosome 6. Genetic distance was shown to the left of the map in centimorgans (cM). The positions of allelic/tightly linked genes Pi2, Piz-t, Pi9, Pi50, and Pigm were integrated on the basis of reported data from Zhou et al. (2006), Qu et al. (2006), Zhu et al. (2012), and Deng et al. (2006). c Resistance evaluation of KFB, LTH, and recombinant F2 individual plants against the rice blast. 1–6: recombinant F2 individuals. d Genotype analysis of six recombinant individuals from the mapping population with flanking markers Rm7213 and InDel-22 and co-segregating markers InDel-19, InDel-25, InDel-27, InDel-28, and SZY04.