Ecological diversification of Bacillus thuringiensis soil isolates was examined to determine whether bacteria adapted to grow at low temperature and/or potentially pathogenic correspond to genetically distinct lineages. Altogether, nine phylogenetic lineages were found among bacilli originating from North-Eastern Poland (n = 24) and Lithuania (n = 25) using multi-locus sequence typing. This clustering was chiefly confirmed by pulsed-field gel electrophoresis. One third of the bacilli were found to be psychrotolerant, which strongly supports the hypothesis of the existence of thermal ecotypes among B. thuringiensis. PCR screening was also performed to detect potential enterotoxin genes and Bacillus anthracis pXO1- and pXO2-like replicons. The cytK-positive isolates (22%) were significantly associated with two phylogenetic lineages (potential CytK pathotypes), whereas there was no correlation between phylogenetic grouping and the presence of the potential tripartite enterotoxin pathotypes (86% of strains). A statistically significant association between phylogenetic lineages and ecologic properties was found with regard to the cry1-positive Lithuanian isolates, while the cry genes in Polish isolates and the pXO1- and pXO2 replicon-like elements showed scattered distribution across phylogenetic lineages. Our results support the hypothesis that B. thuringiensis comprises strains belonging to different phylogenetic lineages, which exhibit specific ecological properties.

We have investigated the influence of mechanical wounding of Arabidopsis rosette leaves on photochemical activity of photosystem II, gas exchange, sugar content and sucrose metabolism in wild-type plants and mutants impaired in hormonal balance. The aos (jasmonate deficiency), rcd1 (reduced sensitivity to ABA, ethylene, and methyl-jasmonate), and ein4 (ethylene insensitivity) mutants have been used. Generally, mechanical injury led to dynamic changes in metabolism, especially in sugar and carotenoid contents. Whereas all mutants showed lower photosynthesis and respiration in comparison to the wildtype plants, leaf wounding caused a decrease in respiration in aos and ein4, and an increase in respiration in wild type. The mechanical injury triggered an increase of the activities of sucrose hydrolysing enzymes, such as sucrose synthase (SuSy) and several types of invertases, which was most evident in case of rcd1 and aos plants. This was correlated with injury-related changes in soluble sugars in the mutants, but not in wild-type plants where sugar content was not significantly affected by wounding. The results confirm the key role of stress hormones, such as jasmonate and ethylene, in mediating stress responses after wounding. The outcome of the experiments also underlines important roles of SuSy and invertase in regeneration of injured tissues, most probably by providing precursors for cell wall biosynthesis and by modulating sugar-signalling in plant cells. Keywords Carbohydrates Á Chlorophyll a fluorescence Á FT-Raman spectroscopy Á Invertase Á Jasmonate-deficient mutant Á Sucrose synthase Abbreviations Aos JA deficient mutant CIN Neutral invertase cwINV Cell wall associated invertase ein4 Ethylene insensitive mutant Fv/Fm Photochemical efficiency of PSII JA Jasmonic acid NPQ Nonphotochemical quenching qP Quenching in steady-state QY Steady-state quantum yield rcd1-1 Radical-induced cell death 1 mutant with reduced sensitivity to ABA, ethylene, and methyl jasmonate ROS Reactive oxygen species SuSy Sucrose synthase VIN Vacuolar invertase W 2 2 h after wounding W 24 24 h after wounding Wt Wild type plants