Ecophysiological Features of Toxigenic Fungi Prevalent in Different Biotopes of Azerbaijan

Abstract

Our research into the ecophysiological features of phytotoxigenic fungi prevalent in different biotopes of Azerbaijan and representing soil-, plant- and water-derived micromycetes biotas are aiming at the determination of the ranges of environmental factors, which favor the fungal prevalence and phytotoxicity. We identified ~130 fungal species (representing the microbiotas of ~2500 samples), out of which 76 species were previously reported as phytotoxigenic. Of these phytotoxigenic fungi, 19 species showed strong (> 50%), 32 species, intermediate (10-50%), and 25 species, weak (<10%) toxicity. The study of abiotic factors contributing to the fungal persistence reveals that, with regards to soil moisture preferences, only 9.5% of phytotoxigenic fungi belong to the hydrophiles, while 55.3% and 35.2% represent the xerophiles and the mesophiles, respectively. According to their thermal preferences, the studied fungi are divided into 89.9% of mesophiles and 10.1% of thermotolerant species. Our research shows that mildly acidic environments (pH~4.9-6.0) favor the intensive growth of most phytotoxigenic fungi. However, some alkaline-tolerant species such as Aspergillus fumigatus, Lichtheimia corymbifera and Mucor hiemalis are able to persist at pH~9. Zygomycetes (Mucor hiemalis, Lichtheimia corymbifera and Rhizomucor miehei) are shown to have microaerophilic features, as far as the fungal oxygen requirements are concerned.