Modeling the metachronous ripening pattern of mature green tomato as affected by cultivar and storage temperature.

Nutritional benefits and organoleptic characteristics, including visual, textural, taste, and flavor, are the critical characteristics of economically important fruit. Ripening is a crucial phenomenon in the formation of these quality characteristics in fruits. Therefore, controlling the ripening phenomenon is extremely important not only to maximize the benefits of the fruit but also to avoid food losses caused by over-ripening. Tomato is an important model plant, especially for research on fruit ripening. The metachronous model of tomato ripening is presented in this report. This model predicts the postharvest ripening time of tomato fruit in terms of red color development based on the storage period. A modified sigmoid-type function model was used to develop the prediction model. The observations and analyses were conducted at different storage temperatures and in different tomato cultivars. The result exhibits that the integration of the proposed model and time lag was successfully showing the postharvest ripening time history of tomato fruit at the full range ripening process, from onset to fully ripe. This study provides critical information on postharvest quality control research and supply chain development in eliminating food loss and waste, which leads to the realization of sustainable development goals.

Epigenetic modifications of the 35S promoter in cultured gentian cells.

Our previous studies found strict gene silencing associated with CaMV-35S promoter-specific de novo methylation in transgenic gentian plants. To dissect the de novo methylation machinery, especially in association with histone modification, 35S-driven sGFP-expressing and -silenced gentian cultured cell lines that originated from a single transformation event were produced and used for epigenetic analyses. A sGFP-expressing primarily induced cell suspension culture (PS) was hypomethylated in the 35S promoter region, although a low level of de novo methylation at the 35S enhancer region (-148 to -85) was detected. In contrast, a sGFP-silenced re-induced cell suspension culture (RS), which originated from leaf tissues of a transgenic plant, was hypermethylated in the 35S promoter region. Chromatin immunoprecipitation analysis showed that in RS, histone H3 of the silenced 35S promoter region was deacetylated and also dimethylated on lysine 9. Interestingly, in the silenced 35S promoter 3' region, dimethylation of histone H3 lysine 4 was also observed. When hypomethylation and histone H3 acetylation of the 35S region occurred in PS, de novo methylation at the 35S enhancer region had already taken place. The de novo methylation status was also resistant to 5-aza-2'-deoxycytidine treatment. These results suggest that de novo methylation of the enhancer region is a primitive process of 35S silencing that triggers histone H3 deacetylation.