Table_4_Chemotaxonomy of Mycotoxigenic Small-Spored Alternaria Fungi – Do Multitoxin Mixtures Act as an Indicator for Species Differentiation?.pdf

Necrotrophic as well as saprophytic small-spored Alternaria (A.) 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 Alternaria toxins. Knowledge of the metabolic capabilities of different species-groups to form mycotoxins is of importance for a reliable risk assessment. 93 Alternaria strains belonging to the four species groups Alternaria tenuissima, A. arborescens, A. alternata, and A. infectoria 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-Alternaria-toxin-method showed that 95% of all strains were able to form at least one of the targeted 17 non-host specific Alternaria toxins. Simultaneous production of up to 15 (modified) Alternaria toxins by members of the A. tenuissima, A. arborescens, A. alternata species-groups and up to seven toxins by A. infectoria 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 A. infectoria 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 A. infectoria strains. Neither by the concentration nor by the composition of the targeted Alternaria toxins a differentiation between the species-groups A. alternata, A. tenuissima and A. arborescens was possible.每年，坏死性及腐生性小分生孢子的 Alternaria (A.) 种类均会导致农业产品，如谷物作物，因食品和饲料受到潜在危害的 Alternaria 毒素污染而遭受重大损失。了解不同物种群体形成霉菌毒素的代谢能力对于可靠的风险评估具有重要意义。从德国和俄罗斯冬季小麦籽粒中分离出 93 个 Alternaria 菌株，分别属于 Alternaria tenuissima、A. arborescens、A. alternata 和 A. infectoria 四个物种群体，并在同等条件下进行培养。通过 HPLC-MS/MS 多 Alternaria 毒素方法进行的化学分析表明，95% 的菌株能够形成目标中的 17 种非宿主特异性 Alternaria 毒素中至少一种。A. tenuissima、A. arborescens 和 A. alternata 物种群体成员能够同时产生多达 15 种（改良的）Alternaria 毒素，而 A. infectoria 菌株则能产生多达 7 种毒素。总体而言，tenuazonic 酸是最广泛形成的霉菌毒素，其次是 alternariol 和 alternariol 单甲基醚，而 altertoxin I 是最常检测到的毒素。alternariol、alternariol 单甲基醚、altenuisol 和 altenuene 的磺基结合形式被频繁确定。此外，还检测到未知的 perylene 氧醌衍生物。由于毒素水平显著较低以及特异性产生 infectopyrone，物种群体 A. infectoria 的菌株可以从其他三个物种群体的菌株中分离出来。除了 infectopyrone 外，95% 的 A. infectoria 菌株还频繁产生 alterperylenol。通过目标 Alternaria 毒素的浓度或组成，无法在物种群体 A. alternata、A. tenuissima 和 A. arborescens 之间进行区分。