D-cysteine desulfhydrase silence influences the level of sugar, organic acid, carotenoids, and polyphenols in tomato fruit

Abstract

Hydrogen sulfide (H2S) plays important roles in the regulation of fruit ripening. D-cysteine desulfhydrase (DCD) is one of the key enzymes of H2S synthesis. However, whether and how DCD is involved in the regulation of tomato fruit quality is still unknown. Here, the tobacco rattle virus (TRV)-based virus-induced gene-silencing (VIGS) was used to silence DCD to explore the effect of DCD on quality regulation in postharvest tomato fruit. The results revealed that DCD silence accelerated the accumulation of fructose, glucose, soluble sugar, soluble protein, carotene, and lycopene. The expressions of the major genes (PFPP, ATPPF, FBA6; GPI, GPD1, POL2; ZDS, CCD7, CrtL-e-1, psy1, LCY1 and PDS) in sugar, acid and carotene metabolism were up-regulated in DCD-silenced tomatoes. DCD silence also decreased the content of malic acid, citric acid, ascorbic acid, total phenols, and total flavonoid by reducing the transcriptional level of their metabolism related genes (MDH, ME1, ME2; CSG, CS3, CSM; MDHAR and DHAR1; PAL5, 4CL, CHS2 and F3H). Meanwhile, the effects of DCD silence on tomato fruit were reversed by the addition of H2S. Thus, H2S might regulate the quality of postharvest tomato fruit through a DCD-dependent pathway.