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Article|01 Feb 2023|OPEN
A D-cysteine desulfhydrase, SlDCD2, participates in tomato fruit ripening by modulating ROS homoeostasis and ethylene biosynthesis
Yu-Qi Zhao1 ,† , Kang-Di Hu1 , ,† , Gai-Fang Yao1 , Si-Yue Wang1 , Xiang-Jun Peng1 and Hua Zhang,1 ,
1School of Food and Biological Engineering, Hefei University of Technology, Hefei 230009, China
*Corresponding author. E-mail: kangdihu@hfut.edu.cn,hzhanglab@hfut.edu.cn
Both authors contributed equally to the study.

Horticulture Research 10,
Article number: uhad014 (2023)
doi: https://doi.org/10.1093/hr/uhad014
Views: 312

Received: 11 Jul 2022
Accepted: 26 Jan 2023
Published online: 01 Feb 2023

Abstract

Hydrogen sulfide (H2S) is involved in multiple processes during plant growth and development. D-cysteine desulfhydrase (DCD) can produce H2S with D-cysteine as the substrate; however, the potential developmental roles of DCD have not been explored during the tomato lifecycle. In the present study, SlDCD2 showed increasing expression during fruit ripening. Compared with the control fruits, the silencing of SlDCD2 by pTRV2-SlDCD2 accelerated fruit ripening. A SlDCD2 gene-edited mutant was constructed by CRISPR/Cas9 transformation, and the mutant exhibited accelerated fruit ripening, decreased H2S release, higher total cysteine and ethylene contents, enhanced chlorophyll degradation and increased carotenoid accumulation. Additionally, the expression of multiple ripening-related genes, including NYC1PAOSGR1PDSPSY1ACO1ACS2, E4, CEL2, and EXP was enhanced during the dcd2 mutant tomato fruit ripening. Compared with the wild-type fruits, SlDCD2 mutation induced H2O2 and malondialdehyde (MDA) accumulation in fruits, which led to an imbalance in reactive oxygen species (ROS) metabolism. A correlation analysis indicated that H2O2 content was strongly positively correlated with carotenoids content, ethylene content and ripening-related gene expression and negatively correlated with the chlorophyll content. Additionally, the dcd2 mutant showed earlier leaf senescence, which may be due to disturbed ROS homeostasis. In short, our findings show that SlDCD2 is involved in H2S generation and that the reduction in endogenous H2S production in the dcd2 mutant causes accelerated fruit ripening and premature leaf senescence. Additionally, decreased H2S in the dcd2 mutant causes excessive H2O2 accumulation and increased ethylene release, suggesting a role of H2S and SlDCD2 in modulating ROS homeostasis and ethylene biosynthesis.