Open AccessHigh CO2/hypoxia-induced softening of persimmon fruit is modulated by DkERF8/16 and DkNAC9 complexes
Author(s) -
Wei Wu,
Miaomiao Wang,
Hui Gong,
Xiaofen Liu,
DaLong Guo,
Ninghui Sun,
Jingwen Huang,
Qingsen Zhu,
Kunsong Chen,
Yin X
Publication year - 2020
Publication title -
journal of experimental botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.616
H-Index - 242
eISSN - 1460-2431
pISSN - 0022-0957
DOI - 10.1093/jxb/eraa009
Subject(s) - diospyros kaki , softening , luciferase , 1 methylcyclopropene , complementation , chemistry , transcription (linguistics) , biochemistry , ethylene , gene , biology , botany , transfection , linguistics , philosophy , phenotype , catalysis , statistics , mathematics
Most persimmon (Diospyros kaki) cultivars are astringent and require post-harvest deastringency treatments such as 95% CO2 (high-CO2 treatment) to make them acceptable to consumers. High-CO2 treatment can, however, also induce excessive softening, which can be reduced by adding 1-methylcyclopropene (1-MCP). Previous studies have shown that genes encoding the ETHYLENE RESPONSE FACTORS (ERFs) DkERF8/16/19 can trans-activate xyloglucan endotransglycosylase/hydrolase (DkXTH9), which encodes the cell wall-degrading enzyme associated with persimmon fruit softening. In this study, RNA-seq data between three treatments were compared, namely high-CO2, high-CO2+1-MCP, and controls. A total of 227 differentially expressed genes, including 17 transcription factors, were predicted to be related to persimmon post-deastringency softening. Dual-luciferase assays indicated that DkNAC9 activated the DkEGase1 promoter 2.64-fold. Synergistic effects on transcription of DkEGase1 that involved DkNAC9 and the previously reported DkERF8/16 were identified. Electrophoretic mobility shift assay indicated that DkNAC9 could physically bind to the DkEGase1 promoter. Bimolecular fluorescence complementation and firefly luciferase complementation imaging assays indicated protein-protein interactions between DkNAC9 and DkERF8/16. Based on these findings, we conclude that DkNAC9 is a direct transcriptional activator of DkEGase1 that can co-operate with DkERF8/16 to enhance fruit post-deastringency softening.