An ETHYLENE RESPONSE FACTOR-MYB Transcription Complex Regulates Furaneol Biosynthesis by Activating QUINONE OXIDOREDUCTASE Expression in Strawberry

• Published in: Plant physiology (Bethesda) Vol. 178; no. 1; pp. 189 - 201
• Main Authors: Zhang, Yuanyuan, Yin, Xueren, Xiao, Yuwei, Zhang, Zuying, Li, Shaojia, Liu, Xiaofen, Zhang, Bo, Yang, Xiaofang, Grierson, Donald, Jiang, Guihua, Klee, Harry J., Chen, Kunsong
• Format: Journal Article
• Language: English
• Published: United States American Society of Plant Biologists 01-09-2018
• Subjects: GENES, DEVELOPMENT AND EVOLUTION
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.18.00598

4-Hydroxy-2,5-dimethyl-3(2H)-furanone is a major contributor to the aroma of strawberry (Fragaria × ananassa) fruit, and the last step in its biosynthesis is catalyzed by strawberry quinone oxidoreductase (FaQR). Here, an ethylene response factor (FaERF#9) was characterized as a positive regulator of the FaQR promoter. Linear regression analysis indicated that FaERF#9 transcript levels were correlated significantly with both FaQR transcripts and furanone content in different strawberry cultivars. Transient overexpression of FaERF#9 in strawberry fruit significantly increased FaQR expression and furaneol production. Yeast one-hybrid assays, however, indicated that FaERF#9 by itself did not bind to the FaQR promoter. An MYB transcription factor (FaMYB98) identified in yeast one-hybrid screening of the strawberry cDNA library was capable of both binding to the promoter and activating the transcription of FaQR by ∼5.6-fold. Yeast two-hybrid assay and bimolecular fluorescence complementation confirmed a direct protein-protein interaction between FaERF#9 and FaMYB98, and in combination, they activated the FaQR promoter 14-fold in transactivation assays. These results indicate that an ERF-MYB complex containing FaERF#9 and FaMYB98 activates the FaQR promoter and up-regulates 4-hydroxy-2,5-dimethyl-3(2H)-furanone biosynthesis in strawberry.