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ARS Home » Pacific West Area » Salinas, California » Crop Improvement and Protection Research » Research » Publications at this Location » Publication #381967
Research Project: Genetics and Breeding of Lettuce, Spinach, Melon, and Related Species to Improve Production and Consumer-related Traits

Location: Crop Improvement and Protection Research

Title: Hypersensitivity to triforine in lettuce is triggered by a TNL gene through the disease resistance pathway

Author
item AN, GUANGHUI - Huazhong Agricultural University
item Simko, Ivan
item CHEN, JIONGJIONG - Huazhong Agricultural University
item YU, CHANGCHUN - Huazhong Agricultural University
item LAVELLE, DEAN - University Of California
item ZHANG, WEIYI - Huazhong Agricultural University
item MICHELMORE, RICHARD - University Of California
item KUANG, H - Huazhong Agricultural University

Submitted to: Plant Biotechnology Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/5/2021
Publication Date: 11/1/2021
Citation: An, G., Simko, I., Chen, J., Yu, C., Lavelle, D., Zhang, W., Michelmore, R., Kuang, H. 2021. Hypersensitivity to triforine in lettuce is triggered by a TNL gene through the disease resistance pathway. Plant Biotechnology Journal. 19(11):2144-2146. https://doi.org/10.1111/pbi.13679.
DOI: https://doi.org/10.1111/pbi.13679

Interpretive Summary: Plants have developed numerous defense mechanisms against pathogens. Defense using resistance genes (R-genes), one of the many defense mechanisms against pathogens, is the best studied mechanism involved in disease resistance. Triforine, an inhibitor of sterol biosynthesis found in certain fungicides, triggers a hypersensitive response (HR) in some lettuce cultivars. Herein, we report the map-based cloning of the Tr gene in lettuce conferring triforine sensitivity. The candidate gene was mapped to an interval harboring a large R-gene family. The rapid and severe HR make the Tr gene a great potential in studies on resistance pathway and plant biotechnology.

Technical Abstract: Triforine, an inhibitor of sterol biosynthesis found in certain fungicides, triggers a hypersensitive response (HR) in some lettuce cultivars. We genetically mapped the Tr gene controlling triforine sensitivity to a locus containing a family of TIR-NBS-LRR-encoding resistance genes (R-genes). Fine mapping showed that only one of the 21 R-gene homologs from the sensitive parent co-segregated with triforine sensitivity. A knockout and complementation test verified that the cosegregating R-gene is the Tr gene controlling triforine sensitivity. Approximately 1% of Lactuca serriola accessions, wild progenitor of lettuce, had the Tr gene and triforine sensitivity, suggesting that the Tr gene originated from L. serriola. RNA-seq and qRT-PCR suggested that triforine sensitivity might engage the resistance pathway. Knockout of the EDS1 gene compromised triforine sensitivity. Triforine triggered a burst of reactive oxygen species (ROS) in sensitive accessions and the HR was alleviated when pretreated with the ROS inhibitor diphenyleneiodonium chloride. We used multiple genetic approaches to pinpoint the Tr gene controlling triforine sensitivity from a large R-gene family. Triforine triggers HR through the resistance pathway with a burst of ROS. The rapid and severe HR make the Tr gene a great potential in studies on resistance pathway and plant biotechnology.