Organ specificity and transcriptional control of metabolic routes revealed by expression QTL profiling of source-sink tissues in a segregating potato population

Background  

With the completion of genome sequences belonging to some of the major crop plants, new challenges arise to utilize this data for crop improvement and increased food security. The field of genetical genomics has the potential to identify genes displaying heritable differential expression associated to important phenotypic traits. Here we describe the identification of expression QTLs (eQTLs) in two different potato tissues of a segregating potato population and query the potato genome sequence to differentiate between cis- and trans-acting eQTLs in relation to gene subfunctionalization.     

The Effect of Carbohydrate and Nitrogen Concentration on Phenol Synthesis in Paul's Scarlet Rose Cells Grown in Tissue Culture

The effects of exogenous concentrations of glucose and nitrate on total ethanol extractable phenols and leucoanthocyanins were studied in Paul's Scarlet Rose cells grown in either liquid suspension or solid culture. Aliquots of liquid suspension cultured cells were harvested during logarithmic, early stationary, and late stationary periods of growth for determination of fresh weight, dry weight, total ethanol extractable phenols and leucoanthocyanins. Cells produced phenols during all phases of growth, but at stationary phase, the production was greatest. Increasing concentrations of exogenous glucose in the culture medium resulted in an increased synthesis of total phenols in logarithmic cells, and an increased synthesis of total phenols and leucoanthocyanin in stationary cells. Addition of increased concentrations of exogenous nitrate to the stationary cells grown in suspension culture markedly reduced synthesis of leucoanthocyanins although total phenol synthesis was not significantly affected. Similar observations were made in cells cultured on solid medium in respect to exogenous glucose concentration, however these cells differed from the suspension cultured cells by having increased amounts of total phenol synthesis and decreased synthesis of leucoanthocyanins in the presence of increasing concentrations of exogenous nitrate in the culture medium.