Polyamines are ubiquitous aliphatic amines that have been implicated in myriad processes, but their precise biochemical roles are not fully understood. We have carried out metabolite profiling analyses of transgenic tomato (Solanum lycopersicum) fruit engineered to accumulate the higher polyamines spermidine (Spd) and spermine (Spm) to bring an insight into the metabolic processes that Spd/Spm regulate in plants. NMR spectroscopic analysis revealed distinct metabolite trends in the transgenic and wild-type/azygous fruits ripened off the vine. Distinct metabolites (glutamine, asparagine, choline, citrate, fumarate, malate, and an unidentified compound A) accumulated in the red transgenic fruit, while the levels of valine, aspartic acid, sucrose, and glucose were significantly lower as compared to the control (wild-type and azygous) red fruit. The levels of isoleucine, glucose, g-aminobutyrate, phenylalanine, and fructose remained similar in the nontransgenic and transgenic fruits. Statistical treatment of the metabolite variables distinguished the control fruits from the transgenic fruit and provided credence to the pronounced, differential metabolite profiles seen during ripening of the transgenic fruits. The pathways involved in the nitrogen sensing/signaling and carbon metabolism seem preferentially activated in the high Spd/Spm transgenics. The metabolite profiling analysis suggests that Spd and Spm are perceived as nitrogenous metabolites by the fruit cells, which in turn results in the stimulation of carbon sequestration. This is seen manifested in higher respiratory activity and up-regulation of phosphoenolpyruvate carboxylase and NADP-dependent isocitrate dehydrogenase transcripts in the transgenic fruit compared to controls, indicating high metabolic status of the transgenics even late in fruit ripening.

Uromyces appendiculatus is a rust fungus that causes disease on beans. To understand more about the biology of U. appendiculatus, we have used multidimensional protein identification technology to survey proteins in germinating asexual uredospores and have compared this data with proteins discovered in an inactive spore. The relative concentrations of proteins were estimated by counting the numbers of tandem mass spectra assigned to peptides for each detected protein. After germination, there were few changes in amounts of accumulated proteins involved in glycolysis, acetyl Co-A metabolism, citric acid cycle, ATP-coupled proton transport, or gluconeogenesis. Moreover, the total amount of translation elongation factors remained high, supporting a prior model that suggests that germlings acquire protein translation machinery from uredospores. However, germlings contained a higher amount of proteins involved in mitochondrial ADP:ATP translocation, which is indicative of increased energy production. Also, there were more accumulating histone proteins, pointing to the reorganization of the nuclei that occurs after germination prior to appressorium formation. Generally, these changes are indicative of metabolic transition from dormancy to germination and are supported by cytological and developmental models of germling growth.