Characterization of Fusarium species causing head blight of highland barley (qingke) in Tibet, China.

Most of the research on the characterization of Fusarium species focused on wheat, barley, rice, and maize in China. However, there has been limited research in highland barley (qingke). Recently, Fusarium head blight (FHB) of qingke was recently observed in Tibet, China, especially around the Brahmaputra River. To gain a better understanding of the pathogens involver, 201 Fusarium isolates were obtained from qingke samples in 2020. Among these isolates, the most abundant species was F. avenaceum (45.3 %), followed by F. equiseti (27.8 %), F. verticillioides (13.9 %), F. acuminatum (9.0 %), F. flocciferum (3.5 %), and F. proliferatum (0.5 %). The distribution of Fusarium species varied along the Brahmaputra River, with F. avenaceum being predominant in the midstream and downstream regions, while F. equiseti was more common in the upstream region. Chemical analyses of all the isolates revealed the production of different mycotoxins by various Fusarium species. It was found that enniatins were produced by F. acuminatum , F. avenaceum , and F. flocciferum , beauvericin (BEA) and fumonisins were produced F. proliferatum and F. verticillioides , and zearalenone (ZEN) and nivalenol (NIV) were produced by F. equiseti. Pathogenicity test showed that F. avenaceum was more aggressive in causing FHB compared to F. acuminatum , F. equiseti, and F. flocciferum. The disease severity, measured by the area under the disease progress curve (AUDPC), was significantly positively (P < 0.01) correlated with the concentration of total toxins produced by each species. Furthermore, all the Fusarium strains which were used for pathogenicity test were susceptible to carbendazim, and the 50 % effective concentration (EC 50) ranged from 0.406 μg/mL to 0.673 μg/mL with an average EC 50 of 0.551 ± 0.012 μg/mL. • This is the first large-scale investigation about the toxigenic Fusarium species from freshly harvested qingke in Tibet, China. • F. avenaceum was the most commonly isolated species in the midstream and downstream of the Brahmaputra River. • Mycotoxins analysis indicated that ENNs were majorly produced by F. acuminatum , F. avenaceum , and F. flocciferumi. • Pathogenicity tests showed that F. avenaceum was more aggressive than F. acuminatum , F. flocciferum , and F. equiseti. [ABSTRACT FROM AUTHOR]