Amino acid substitutions in a polygalacturonase inhibiting protein (OsPGIP2) increases sheath blight resistance in rice

• Main Authors: Xijun Chen, Yuwen Chen, Lina Zhang, Zhen He, Benli Huang, Chen Chen, Qingxia Zhang, Shimin Zuo
• Format: Article
• Language: English
• Published: SpringerOpen 2019-07-01
• Series: Rice
• Subjects: Polygalacturonase inhibiting proteins; Amino acid substitution; Sheath blight resistance; Rice
• Online Access: http://link.springer.com/article/10.1186/s12284-019-0318-6
• ISSN: 1939-8425; 1939-8433

Abstract Background An economic strategy to control plant disease is to improve plant defense to pathogens by deploying resistance genes. Plant polygalacturonase inhibiting proteins (PGIPs) have a vital role in plant defense against phytopathogenic fungi by inhibiting fungal polygalacturonase (PG) activity. We previously reported that rice PGIP1 (OsPGIP1) inhibits PG activity in Rhizoctonia solani, the causal agent of rice sheath blight (SB), and is involved in regulating resistance to SB. Result Here, we report that OsPGIP2, the protein ortholog of OsPGIP1, does not possess PGIP activity; however, a few amino acid substitutions in a derivative of OsPGIP2, of which we provide support for L233F being the causative mutation, appear to impart OsPGIP2 with PG inhibition capability. Furthermore, the overexpression of mutated OsPGIP2 L233F in rice significantly increased the resistance of transgenic lines and decreased SB disease rating scores. OsPGIP2 L233F transgenic lines displayed an increased ability to reduce the tissue degradation caused by R. solani PGs as compared to control plants. Rice plants overexpressing OsPGIP2 L233F showed no difference in agronomic traits and grain yield as compared to controls, thus demonstrating its potential use in rice breeding programs. Conclusions In summary, our results provide a new target gene for breeding SB resistance through genome-editing or natural allele mining.