Identification of Bacillus Species Isolated from Picea abies by Physiological Tests, Phage Typing and Fatty Acid Analysis

The bacterial species inhabiting Norway spruce (Picea abies (L.) H. Karsten) were investigated, with special attention paid to Bacillus species. The trees had been inoculated one or five growing seasons earlier with a mixture of fungi and bacteria to observe the interaction of externally introduced microbes with a living tree. After both one and five growing seasons, the most frequent Bacillus species was B. pumilus. The second most frequent species were B. subtilis and B. cereus. B. pumilus strains were pectolytic and B. subtilis were cellulolytic, which probably enabled them to attack the bordered pits of xylem cells. The Bacillus strains collected from the trees were identified by classical physiological tests, by determination of whole-cell fatty acid composition, and by phage typing. Results from these three analytical techniques were in good agreement. Whole-cell fatty acid analysis was found to be sufficiently accurate to be used alone as a routine method for the identification of Bacillus species inhabiting living spruce.