Functional analysis of auxin receptor OsTIR1/OsAFB family members in rice grain yield, tillering, plant height, root system, germination, and auxinic herbicide resistance. Issue 5 (10th December 2020)

• Record Type: Journal Article
• Authors: Guo, Fu; Huang, Yizi; Qi, Peipei; Lian, Guiwei; Hu, Xingming; Han, Ning; Wang, Junhui; Zhu, Muyuan; Qian, Qian; Bian, Hongwu
• Is Part Of: New phytologist. Volume 229:Issue 5(2021)
• Page Start: 2676
• Page End: 2692
• Publication Date: 2020-12-10
• Subjects: auxin receptors -- auxin resistance -- herbicide -- miR393 -- OsTIR1/OsAFBs -- picloram -- rice; Botany -- Periodicals; 580
• DOI: 10.1111/nph.17061
• Languages: English
• ISSNs: 0028-646X

Abstract

Summary: Auxin regulates almost every aspect of plant growth and development and is perceived by the TIR1/AFB auxin co‐receptor proteins differentially acting in concert with specific Aux/IAA transcriptional repressors. Little is known about the diverse functions of TIR1/AFB family members in species other than Arabidopsis. We created targeted OsTIR1 and OsAFB2 – 5 mutations in rice using CRISPR/Cas9 genome editing, and functionally characterized the roles of these five members in plant growth and development and auxinic herbicide resistance. Our results demonstrated that functions of OsTIR1/AFB family members are partially redundant in grain yield, tillering, plant height, root system and germination. Ostir1, Osafb2 and Osafb4 mutants exhibited more severe phenotypes than Osafb3 and Osafb5 . The Ostir1Osafb2 double mutant displays extremely severe defects in plant development. All five OsTIR1/AFB members interacted with OsIAA1 and OsIAA11 proteins in vivo . Root elongation assay showed that each Ostir1/afb2–5 mutant was resistant to 2, 4‐dichlorophenoxyacetic acid (2, 4‐D) treatment. Notably, only the Osafb4 mutants were strongly resistant to the herbicide picloram, suggesting that OsAFB4 is a unique auxin receptor in rice. Our findings demonstrate similarities and specificities of auxin receptor TIR1/AFB proteins in rice, and could offer the opportunity to modify effective herbicide‐resistant alleles in agronomically important crops.