Isolation and Identification of Six Newly Recorded Wheat Fusarium Crown Rot-Associated Fusarium Species.

Fusarium crown rot (FCR) has become one of the most serious diseases affecting wheat production worldwide. To date, many Fusarium species associated with wheat FCR disease have been reported. To gain a deeper understanding of Fusarium species diversity associated with wheat FCR, extensive research was conducted to identify different Fusarium 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 Fusarium isolates were obtained from collected samples and identified using sequence analysis of the translation elongation factor-1α (TEF-1α), RNA polymerase II largest subunit (RPB1), and RNA polymerase II second largest subunit (RPB2) gene sequences. Of these Fusarium isolates, 1,082 were identified as Fusarium pseudograminearum, and the remaining isolates were identified as F. graminearum (n = 338), F. asiaticum (n = 41), F. proliferatum (n = 17), F. sinensis (n = 8), F. oxysporum (n = 7), F. acuminatum (n = 6), F. verticillioides (n = 5), F. nanum (n = 3), F. sulawesiense (n = 2), F. fujikuroi (n = 1), F. odoratissimum (n = 1), and F. reticulatum (n = 1). Among the 13 Fusarium species, F. verticillioides, F. nanum, F. sulawesiense, F. fujikuroi, F. odoratissimum, and F. reticulatum 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 Fusarium species on the major wheat cultivar 'Jimai 22' revealed that all the tested isolates caused FCR disease. This is the first report of F. fujikuroi, F. nanum, F. odoratissimum, F. reticulatum, F. sulawesiense, and F. verticillioides causing wheat FCR worldwide.