Stomata are essential for photosynthesis and water-use efficiency in plants. When expressed in transgenic Arabidopsis thaliana plants, the potato (Solanum tuberosum) proteins EPIDERMAL PATTERNING FACTOR 2 (StEPF2) and StEPF-LIKE9 (StEPFL9) play antagonistic roles in regulating stomatal density. Little is known, however, about how these proteins regulate stomatal development, growth, and response to water deficit in potato. Transgenic potato plants overexpressing StEPF2 (E2 plants) or StEPFL9 (ST plants) were generated, and RT-PCR and Western blot analyses were used to select two lines overexpressing each gene. E2 plants showed reduced stomatal density, whereas ST plants produced excessive stomata. Under well-watered conditions, ST plants displayed vigorous growth with improved leaf gas exchange and also showed increased biomass/yields compared with non-transgenic and E2 plants. E2 plants maintained lower H₂O₂ content and higher levels of stomatal conductance and photosynthetic capacity than non-transgenic and ST plants, which resulted in higher water-use efficiency and biomass/yields during water restriction. These results suggest that StEPF2 and StEPFL9 functioned in pathways regulating stomatal development. These genes are thus promising candidates for use in future breeding programs aimed at increasing potato water-use efficiency and yield under climate change scenarios.

Genipin, one of Gardenia jasminoides’ bioactive components, exhibits superior therapeutic efficacy compared to geniposide, though it is present in much lower concentrations. Conventional hydrolysis methods using acids or organic solvents can enhance genipin yield but often raise environmental and safety concerns. This study aimed to increase genipin production through whole-cell bioconversion of geniposide to genipin using lactic acid bacteria (LABs). A total of 191 LAB strains were isolated from kimchi. Levilactobacillus sp. LN180102 showed the highest bioconversion activity, which was up to 40%. Docking analysis and esculin assay confirmed the beta-glucosidase activity. The anti-inflammatory effects of the fermented extract were enhanced by 28.5% in RAW 264.7 cells in vitro. Additionally, Levilactobacillus sp. LN180102 is probiotic-friendly and exhibits a high tolerance for phenol, bile, and acid. In their entirety, these discoveries have the potential to illuminate the ways in which Gardenia jasminoides can be functionally improved through whole-cell bioconversion, thereby enabling individuals to lead healthier lifestyles.