Changes in the nucleoside-nucleotide pools of Uromyces viciae-fabae uredospores during imbibition at low temperature

Uromyces viciae-fabae uredospores were imbibed in iced water and their nucleoside, nucleotide and UDP-sugar contents were analysed by high performance liquid chromatography. During low temperature treatment the initial high nucleoside content decreased to rather low levels, and this was accompanied by efficient generation of nucleoside triphosphates and UDP-sugars. Part of the uridine content may have been used to produce high amounts of UDP- N-acetylglucosamine. Whereas this latter process occurred continuously, the synthesis of the nucleoside triphosphates showed two distinct phases. During the first 2 h activation of energy metabolism (ATP production) took place. This was followed by a phase during which all four nucleoside triphosphates were generated. This suggests metabolic preparation for biopolymer and phospholipid synthesis, although morphological changes associated with germ tube emergence were not visible during experiment.