Deciphering the Role of CBF/DREB Transcription Factors and Dehydrins in Maintaining the Quality of Table Grapes cv. Autumn Royal Treated with High CO2 Levels and Stored at 0°C

Abstract

C-repeat/dehydration-responsive element binding factors (CBF/DREB) are transcription factors which play a role in improving plant cold stress resistance and recognize the DRE/CRT element in the promoter of a set of cold regulated genes. Dehydrins (DHNs) are proteins that accumulate in plants in response to cold stress, which present, in some cases, CBF/DREB recognition sequences in their promoters and are activated by members of this transcription factor family. The application of a 3-day gaseous treatment with 20 kPa CO2 at 0°C to table grapes cv. Autumn Royal maintained the quality of the bunches during postharvest storage at 0°C, reducing weight loss and rachis browning. In order to determine the role of CBF/DREB genes in the beneficial effect of the gaseous treatment by regulating DHNs, we have analyzed the gene expression pattern of three VviDREBA1s (VviDREBA1-1, VviDREBA1-6, and VviDREBA1-7) as well as three VviDHNs (VviDHN1a, VviDHN2, and VviDHN4), in both alternative splicing forms. Results showed that the differences in VviDREBA1s expression were tissue and atmosphere composition dependent, although the application of high levels of CO2 caused a greater increase of VviDREBA1-1 in the skin, VviDREBA1-6 in the pulp and VviDREBA1-7 in the skin and pulp. Likewise, the application of high levels of CO2 regulated the retention of introns in the transcripts of the dehydrins studied in the different tissues analyzed. The DHNs promoter analysis showed that VviDHN2 presented the cis-acting DRE and CRT elements, whereas VviDHN1a presented only the DRE motif. Our electrophoretic mobility shift assays (EMSA) showed that VviDREBA1-1 was the only transcription factor that had in vitro binding capacity to the CRT element of the VviDHN2 promoter region, indicating that the transcriptional regulation of VviDHN1a and VviDHN4 would be carried out by activating other independent routes of these transcription factors. Our results suggest that the application of high CO2 levels to maintain table grape quality during storage at 0°C, leads to an activation of CBF/DREBs transcription factors. Among these factors, VviDREBA1-1 seems to participate in the transcriptional activation of VviDHN2 via CRT binding, with the unspliced form of this DHN being activated by high CO2 levels in all the tissues analyzed.

Effect of high levels of CO2on the electrochemical behavior and the enzymatic and non‐enzymatic antioxidant systems in black and white table grapes stored at 0 °C

“…As a consequence, the incorporation of postharvest technologies that reduce the use of agrochemical compounds is vital to maintain the quality of fruit and vegetables during their storage. The application of a gaseous treatment with 20 kPa CO 2 for 3 days at 0 °C was effective in maintaining the quality of red table grapes during postharvest storage at low temperature by reducing total decay, weight loss, and rachis browning . Although table grapes are classified as chilling tolerant, our previous works have shown that the 3‐day gaseous treatment helped red table grapes to withstand temperature shifts at 0 °C .…”

“…Actin1 (XM_002282480) from V. vinifera was used as internal control. The specificity of products was validated as described by Vazquez‐Hernandez et al …”

“…b). In previous works, we have pointed out that the 3‐day high CO 2 treatment helped red / black table grapes (Cardinal or Autumn Royal) to withstand temperature shifts at 0 °C and thus CO 2 ‐treated berries demonstrated low ion leakage, water loss, and rachis browning in comparison to non‐treated ones. Likewise, a microarray analysis revealed substantial changes in the transcriptome of Cardinal table grapes as a response to storage at 0 °C, whereas the number of genes that changed expression because of the 3‐day CO 2 was much lower .…”

“…Total decay was expressed as the percentage of decayed berries at day 28 with respect to the original cluster weight. Rachis browning at day 28 was determined by using the subjective scale, as indicated by Vazquez‐Hernandez et al …”

“…The application of a gaseous treatment with 20 kPa CO 2 for 3 days at 0 ∘ C was effective in maintaining the quality of red table grapes during postharvest storage at low temperature by reducing total decay, weight loss, and rachis browning. [1][2][3] Although table grapes are classified as chilling tolerant, our previous works have shown that the 3-day gaseous treatment helped red table grapes to withstand temperature shifts at 0 ∘ C. 1,3 However, it is important to mention that, to date, the effectiveness of the 3-day gaseous treatment has only been analyzed in red table grapes.…”