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Studies on the Mechanism of Action of 2-Aminobutane. J. A. Bartz, Former Research Fellow, Environmental Sciences Program, University of California, Riverside, now Assistant Professor of Plant Pathology, University of Florida, Gainesville 32601; J. W. Eckert, Professor of Plant Pathology, University of California, Riverside 92502. Phytopathology 62:239-246. Accepted for publication 8 September 1971. DOI: 10.1094/Phyto-62-239.

Concentrations of the 2-aminobutane cation (2AB) that reduced the growth rate of Penicillium digitatum by 50% or more had no direct effect upon respiration or ability of treated cells to retain lower molecular weight metabolites. The level of K+ in germinating conidia was reduced 50% by 1 mM 2AB, but even lower levels of K+ were sufficient for growth in the absence of 2AB. 2-Aminobutane inhibited the transport of ¹⁴C-labeled proline, lysine, glutamic acid, and leucine by 50-70% of the control value, and the incorporation of the label into protein to about the same extent. Uptake and incorporation of ³³P-phosphate into ribonucleic acid was also inhibited in the presence of 2AB. Cultures grown in an amino acid-free medium showed a greater increase in dry weight than 2AB-treated cultures growing in a complete medium. This indicated that inhibited transport of amino acids was not limiting the rate of growth.