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Gao Y, Fan ZQ, Zhang Q, Li HL, Liu GS, Jing Y, Zhang YP, Zhu BZ, Zhu HL, Chen JY, Grierson D, Luo YB, Zhao XD, Fu DQ. A tomato NAC transcription factor, SlNAM1, positively regulates ethylene biosynthesis and the onset of tomato fruit ripening. Plant J 2021; 108:1317-1331. [PMID: 34580960 DOI: 10.1111/tpj.15512] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 09/09/2021] [Accepted: 09/21/2021] [Indexed: 06/13/2023]
Abstract
Fruit ripening in tomato (Solanum lycopersicum) is the result of selective expression of ripening-related genes, which are regulated by transcription factors (TFs). The NAC (NAM, ATAF1/2, and CUC2) TF family is one of the largest families of plant-specific TFs and members are involved in a variety of plant physiological activities, including fruit ripening. Fruit ripening-associated NAC TFs studied in tomato to date include NAC-NOR (non-ripening), SlNOR-like1 (non-ripening like1), SlNAC1, and SlNAC4. Considering the large number of NAC genes in the tomato genome, there is little information about the possible roles of other NAC members in fruit ripening, and research on their target genes is lacking. In this study, we characterize SlNAM1, a NAC TF, which positively regulates the initiation of tomato fruit ripening via its regulation of ethylene biosynthesis. The onset of fruit ripening in slnam1-deficient mutants created by CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats and CRISPR-associated protein 9) technology was delayed, whereas fruit ripening in OE-SlNAM1 lines was accelerated compared with the wild type. The results of RNA-sequencing (RNA-seq) and promoter analysis suggested that SlNAM1 directly binds to the promoters of two key ethylene biosynthesis genes (1-aminocyclopropane-1-carboxylate synthase: SlACS2 and SlACS4) and activates their expression. This hypothesis was confirmed by electrophoretic mobility shift assays and dual-luciferase reporter assay. Our findings provide insights into the mechanisms of ethylene production and enrich understanding of the tomato fruit ripening regulatory network.
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Affiliation(s)
- Ying Gao
- Laboratory of Fruit Biology, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing, 100083, China
- Laboratory of Fruit Quality Biology, Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Zijingang Campus, Hangzhou, 310058, China
| | - Zhong-Qi Fan
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables, College of Horticulture, South China Agricultural University, Guangzhou, 510642, China
- Institute of Postharvest Technology of Agricultural Products, College of Food Science, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Qiang Zhang
- School of Biology and Basic Medical Sciences, Soochow University, Suzhou, 215000, China
| | - Hong-Li Li
- Laboratory of Fruit Biology, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing, 100083, China
| | - Gang-Shuai Liu
- Laboratory of Fruit Biology, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing, 100083, China
| | - Yuan Jing
- Laboratory of Fruit Biology, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing, 100083, China
| | - Yi-Ping Zhang
- Laboratory of Fruit Biology, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing, 100083, China
| | - Ben-Zhong Zhu
- Laboratory of Fruit Biology, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing, 100083, China
| | - Hong-Liang Zhu
- Laboratory of Fruit Biology, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing, 100083, China
| | - Jian-Ye Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables, College of Horticulture, South China Agricultural University, Guangzhou, 510642, China
| | - Donald Grierson
- Laboratory of Fruit Quality Biology, Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Zijingang Campus, Hangzhou, 310058, China
- Plant Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - Yun-Bo Luo
- Laboratory of Fruit Biology, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing, 100083, China
| | - Xiao-Dan Zhao
- School of Food and Chemical Engineering, Beijing Technology and Business University, Beijing, 100048, China
| | - Da-Qi Fu
- Laboratory of Fruit Biology, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing, 100083, China
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