Recently, the Functional Genomics of Crop Pathogens Research Innovation Team at the Institute of Plant Protection, Chinese Academy of Agricultural Sciences (IPPCAAS), published a study titled  Development of elite rice with broad-spectrum resistance through pyramiding of key resistance gene and simultaneously editing multiple susceptibility genes  in the  Journal of Integrative Plant Biology . This research utilized gene-editing technology to simultaneously knock out susceptibility genes in the breeding intermediate line 07GY31-Piz-t, achieving improved broad-spectrum resistance against rice blast and bacterial blight. 

Rice blast and bacterial blight severely threaten rice yield and quality, making the development of rice varieties with broad-spectrum resistance a key objective for breeders. Introducing resistance (R) genes can only target Magnaporthe oryzae races carrying corresponding avirulence genes while knocking out susceptibility (S) factors significantly enhances resistance. However, resistance levels mediated by S factors are far lower than those conferred by R genes. Combining the qualitative resistance of R genes with the quantitative resistance from S factors is critical for creating novel materials with broad-spectrum resistance (BSR). 

In prior work, the team led by Researcher Yuesuo Ning demonstrated that triple knockout of S factors Pi21, Bsr-d1, and Xa5 in the Nipponbare background (pbxcas9/NPB) significantly enhanced resistance to both rice blast and bacterial blight. However, pbxcas9/NPB exhibited weak resistance against M. oryzae races incompatible with the R gene Piz-t. The intermediate breeding line 07GY31-Piz-t, previously developed via molecular design breeding, was further modified by knocking out Pi21, Bsr-d1, and Xa5 to create the pbxcas9/07GY31-Piz-t line. This line exhibited markedly enhanced broad-spectrum resistance to both diseases without compromising other agronomic traits. The study exemplifies the effective integration of molecular design breeding and gene editing to engineer plant BSR materials, offering new germplasm resources for rice disease resistance breeding and innovative strategies for improving resistance in other crops.

Postdoctoral researcher Hui Tao from IPPCAAS, is the leading author of the paper, with Researcher Yuesuo Ning serving as the corresponding author. The research also involved contributions from Researcher Aihong Li and Researcher Ning Xiao of the Jiangsu Lixiahe Regional Institute of Agricultural Sciences, Associate Professor Dan Wang from Hunan Agricultural University, and others. The study was supported by the National Key Research and Development Program, the National Natural Science Foundation of China, and the Agricultural Science and Technology Innovation Program of CAAS. 

The pbxcas9/07GY31-Piz-t line exhibits broad-spectrum resistance to rice blast and bacterial blight.

Source: https://onlinelibrary.wiley.com/doi/full/10.1111/jipb.13901