Project description:Bitter pit is the most important physiological disorder affecting apples. In order to ascertain the genetic bases of its incidence in apple fruit, a mapping population of ‘Braeburn’ (susceptible to bitter pit) × ‘Cameo’ (resistant to bitter pit) cultivars was used to map the trait over two growing seasons. RNA-Seq on pools of RNA extracted from fruits of three resistant and three susceptible to bitter pit progenies at post-fertilization and full maturity stages, permitted us to identify a number of candidate genes underlying genetic resistance/susceptibility to bitter pit.
Project description:T2R bitter receptors, encoded by Tas2r genes, are not only critical for bitter taste signal transduction but also important for defense against bacteria and parasites. However, little is known about whether and how Tas2r gene expression are regulated. Here, using single-cell assays for transposase-accessible chromatin with sequencing (scATAC-seq), we found that the chromatin accessibility of Tas2rs was highly cell type specific and lipopolysaccharide (LPS)-induced inflammation increased the accessibility of many Tas2rs. scATAC-seq also revealed substantial chromatin remodeling in immune response genes in taste tissue stem cells, suggesting potential long-term effects. Together, our results suggest an epigenetic mechanism connecting inflammation, Tas2r gene regulation, and altered bitter taste, which may explain heightened bitter taste that can occur with infections and cancer treatments.
Project description:This study investigated the impact of individual lactococcal starter cultures on peptide formation and bitter peptide accumulation during cheese aging using a novel mini-scale cheese production system. Cheeses were produced using single-strain fermentations of Lactococcus lactis and Lactococcus cremoris and aged for 45 and 90 days. Peptide profiles were analyzed using LC-MS/MS-based peptidomics to characterize strain-specific proteolytic patterns and bitter peptide generation from casein proteins. The resulting peptide profiles demonstrated strong strain specificity and reproducibility among replicates. Particular emphasis was placed on bitter peptides derived from β-casein and αS1-casein regions associated with cheese bitterness. Two L. lactis strains, E2-4M12 and E1-6M12, consistently produced lower abundances of bitter peptides despite substantial overall peptide abundance, suggesting unique proteolytic characteristics. Comparative analysis between CEP-positive and CEP-negative strains indicated that CEP genotype alone was not a primary determinant of bitter peptide accumulation. These findings contribute to understanding how starter culture selection influences cheese proteolysis and bitterness development during ripening.
Project description:We generated 95.37 Gb of high-quality sequencing data (~7.95 Gb per sample). The analysis showed differences of transcriptomes between the common white sweet quinoa and the yellow bitter quinoa. We identified numerous differentially expressed genes that exhibited distinct expression patterns. These genes have known or potential roles in taste of quinoa fruit.Therefore, we are appealing candidates for further investigation of the gene expression and associated regulatory mechanisms related to the accumulation of bitter saponins in C. quinoa fruits.