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Article|01 Feb 2020|OPEN
Roles of SlETR7, a newly discovered ethylene receptor, in tomato plant and fruit development
Yi Chen1,2, Guojian Hu1,2, Celeste Rodriguez3, Meiying Liu2,4, Brad M. Binder3 & Christian Chervin2,
1College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, China
2Genomics and Biotechnology of Fruits, University of Toulouse, INRA, ENSAT, 31326 Castanet-Tolosan, France
3Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA
4Weifang University, Weifang 261041 Shandong, China

Horticulture Research 7,
Article number: 20017 (2020)
doi: 10.1038/hortres.2020.17
Views: 378

Received: 10 Oct 2019
Revised: 06 Dec 2019
Accepted: 11 Dec 2019
Published online: 01 Feb 2020

Abstract

Ethylene regulates many aspects of plant growth and development. It is perceived by a family of ethylene receptors (ETRs) that have been well described. However, a full understanding of ETR function is complicated by functional redundancy between the receptor isoforms. Here, we characterize a new ETR, SlETR7, that was revealed by tomato genome sequencing. SlETR7 expression in tomato fruit pericarp increases when the fruit ripens and its expression is synchronized with the expression of SlETR1, SlETR2, and SlETR5 which occurs later in the ripening phase than the increase observed for SlETR3, SlETR4, and SlETR6. We uncovered an error in the SlETR7 sequence as documented in the ITAG 3 versions of the tomato genome which has now been corrected in ITAG 4, and we showed that it belongs to sub-family II. We also showed that SlETR7 specifically binds ethylene. Overexpression (OE) of SlETR7 resulted in earlier flowering, shorter plants, and smaller fruit than wild type. Knock-out (KO) mutants of SlETR7 produced more ethylene at breaker (Br) and Br + 2 days stages compared to wild type (WT), but there were no other obvious changes in the plant and fruit in these mutant lines. We observed that expression of the other SlETRs is upregulated in fruit of SlETR7 KO mutants, which may explain the absence of obvious ripening phenotypes. Globally, these results show that SlETR7 is a functional ethylene receptor. More work is needed to better understand its specific roles related to the six other tomato ETRs.