Ribonucleic acid synthesis during fungal spore germination.

Spores of several fungi were examined in an effort to understand the role of RNA in the biochemical events occurring early in germination. RNA synthesis appeared to be an essential requirement for germination in Neurospora crassa and Aspergillus nidulans but not in Alternaria solani and Peronospora tabacina. Gross changes in the relative amounts of the various molecular species of RNA were not detected during germination of P. tabacina and N. crassa spores. Pulse-labelling of the germinating spores revealed that, in N . crassa, ribosomal and soluble RNAs were the major species being synthesized, whereas in P. tabacina label was incorporated into soluble RNA and an unstable heterodisperse RNA, but apparently not into ribosomal RNA, This pattern of RNA synthesis in germinating P. tabacina spores is similar to that found in cleaving embryos of certain animals where development is also rapid and, like germinating P. tabacina spores, can occur when RNA synthesis is inhibited.