Dof Transcription Factors Are Involved in High CO2 Induced Persimmon Fruit Deastringency

Abstract

High CO2 treatment is a widely used deastringency technology that causes the accumulation of acetaldehyde which precipitates the astringent soluble tannins from persimmon fruit, making them more attractive to consumers. The identification of DkADH1 and DkPDC2 (the key genes for acetaldehyde accumulation) and their regulators (e.g., ERFs), has significantly advanced our understanding of the fruit deastringency mechanism, but other TFs are also involved in the high CO2 response. Here, 32 DkDofs genes were identified from ‘Gongcheng-shuishi’ persimmon, with nine of them shown to differentially respond to high CO2 treatment. Dual luciferase assay indicated that DkDof3 and DkDof6 could repress the promoters of DkADH1 and DkPDC2, respectively. EMSA assay showed that DkDof3 and DkDof6 physically interacted with probes containing T/AAAAG elements from the DkADH1 promoter, whereas they failed to recognize similar elements from the DkPDC2 promoter. The expression of DkDof3 and DkDof6 was also found to be repressed in different persimmon cultivars in response to high CO2 treatment. It is proposed that DkDof3 and DkDof6 were involved in fruit deastringency by regulating the expression of DkADH1 and DkPDC2 in different persimmon cultivars.