Isolation and Identification of Six Newly Recorded Wheat Fusarium Crown Rot-Associated <i>Fusarium</i> Species

Fusarium crown rot (FCR) has become one of the most serious diseases affecting wheat production worldwide. To date, many <i>Fusarium</i> species associated with wheat FCR disease have been reported. To gain a deeper understanding of <i>Fusarium</i> species diversity associated with wheat FCR, extensive research was conducted to identify different <i>Fusarium</i> species. A total of 194 diseased wheat samples were collected from Dezhou, Heze, Jining, Linyi, Qingdao, Rizhao, Weihai, and Zaozhuang cities of Shandong Province, China. A total of 1,512 <i>Fusarium</i> isolates were obtained from collected samples and identified using sequence analysis of the translation elongation factor-1α (<i>TEF-1α</i>), RNA polymerase II largest subunit (<i>RPB1</i>), and RNA polymerase II second largest subunit (<i>RPB2</i>) gene sequences. Of these <i>Fusarium</i> isolates, 1,082 were identified as <i>Fusarium pseudograminearum</i>, and the remaining isolates were identified as <i>F. graminearum</i> (<i>n</i> = 338), <i>F. asiaticum</i> (<i>n</i> = 41), <i>F. proliferatum</i> (<i>n</i> = 17), <i>F. sinensis</i> (<i>n</i> = 8), <i>F. oxysporum</i> (<i>n</i> = 7), <i>F. acuminatum</i> (<i>n</i> = 6), <i>F. verticillioides</i> (<i>n</i> = 5), <i>F. nanum</i> (<i>n</i> = 3), <i>F. sulawesiense</i> (<i>n</i> = 2), <i>F. fujikuroi</i> (<i>n</i> = 1), <i>F. odoratissimum</i> (<i>n</i> = 1), and <i>F. reticulatum</i> (<i>n</i> = 1). Among the 13 <i>Fusarium</i> species, <i>F. verticillioides</i>, <i>F. nanum</i>, <i>F. sulawesiense</i>, <i>F. fujikuroi</i>, <i>F. odoratissimum</i>, and <i>F. reticulatum</i> were obtained from wheat FCR samples for the first time and were considered six new record species. Pathogenicity tests of all the six newly recorded <i>Fusarium</i> species on the major wheat cultivar 'Jimai 22' revealed that all the tested isolates caused FCR disease. This is the first report of <i>F. fujikuroi</i>, <i>F. nanum</i>, <i>F. odoratissimum</i>, <i>F. reticulatum</i>, <i>F. sulawesiense</i>, and <i>F. verticillioides</i> causing wheat FCR worldwide.