AUTHOR=Zwickel Theresa , Kahl Sandra M. , Rychlik Michael , Müller Marina E. H. 

TITLE=Chemotaxonomy of Mycotoxigenic Small-Spored Alternaria Fungi – Do Multitoxin Mixtures Act as an Indicator for Species Differentiation?

JOURNAL=Frontiers in Microbiology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2018.01368

DOI=10.3389/fmicb.2018.01368

ISSN=1664-302X

ABSTRACT=<p>Necrotrophic as well as saprophytic small-spored <italic>Alternaria (A.)</italic> species are annually responsible for major losses of agricultural products, such as cereal crops, associated with the contamination of food and feedstuff with potential health-endangering <italic>Alternaria</italic> toxins. Knowledge of the metabolic capabilities of different species-groups to form mycotoxins is of importance for a reliable risk assessment. 93 <italic>Alternaria</italic> strains belonging to the four species groups <italic>Alternaria tenuissima</italic>, <italic>A. arborescens</italic>, <italic>A. alternata</italic>, and <italic>A. infectoria</italic> were isolated from winter wheat kernels harvested from fields in Germany and Russia and incubated under equal conditions. Chemical analysis by means of an HPLC-MS/MS multi-<italic>Alternaria</italic>-toxin-method showed that 95% of all strains were able to form at least one of the targeted 17 non-host specific <italic>Alternaria</italic> toxins. Simultaneous production of up to 15 (modified) <italic>Alternaria</italic> toxins by members of the <italic>A. tenuissima</italic>, <italic>A. arborescens</italic>, <italic>A. alternata</italic> species-groups and up to seven toxins by <italic>A. infectoria</italic> strains was demonstrated. Overall tenuazonic acid was the most extensively formed mycotoxin followed by alternariol and alternariol mono methylether, whereas altertoxin I was the most frequently detected toxin. Sulfoconjugated modifications of alternariol, alternariol mono methylether, altenuisol and altenuene were frequently determined. Unknown perylene quinone derivatives were additionally detected. Strains of the species-group <italic>A. infectoria</italic> could be segregated from strains of the other three species-groups due to significantly lower toxin levels and the specific production of infectopyrone. Apart from infectopyrone, alterperylenol was also frequently produced by 95% of the <italic>A. infectoria</italic> strains. Neither by the concentration nor by the composition of the targeted <italic>Alternaria</italic> toxins a differentiation between the species-groups <italic>A. alternata</italic>, <italic>A. tenuissima</italic> and <italic>A. arborescens</italic> was possible.</p>