First Report of Fusarium temperatum Causing Seedling Blight and Stalk Rot on Maize in Spain

In Europe, several diseases of maize (Zea mays L.) including seedling blight and stalk rot are caused by different Fusarium species, mainly Fusarium graminearum, F. verticillioides, F. subglutinans, and F. proliferatum (3). In recent years, these Fusarium spp. have received significant attention not only because of their impact on yield and grain quality, but also for their association with mycotoxin contamination of maize kernels (1,4). From October 2011 to October 2012, surveys were conducted in a maize plantation located in Galicia (northwest Spain). In each sampling, 100 kernels and 10 maize stalks were collected from plants exhibiting symptoms of ear and stalk rot. Dried kernels and small stalk pieces (1 to 2 cm near the nodes) were placed onto potato dextrose agar medium and incubated in the dark for 7 days. Fungal colonies displaying morphological characteristics of Fusarium spp. (2) were subcultured as single conidia onto SNA (Spezieller Nahrstoffarmer agar) (2) and identified by morphological characteristics, as well as by DNA sequence analysis. A large number of Fusarium species (F. verticillioides, F. subglutinans, F. graminearum, and F. avenaceum) (1,2) were identified. These Fusarium species often cause ear and stalk rot on maize. In addition, a new species, F. temperatum, recently described in Belgium (3), was also identified. F. temperatum is within the Gibberella fujikuroi species complex and is morphologically and phylogenetically closely related to F. subglutinans (2,3). Similar to previous studies (3), our isolates were characterized based on the presence of white cottony mycelium, becoming pinkish white. Conidiophores were erect, branched, and terminating in 1 to 3 phialides. Microconidia were abundant, hyaline, 0 to 2 septa; ellipsoidal to oval, produced singly or in false heads, and on monophialides, intercalary phialides, and polyphialides. Microconidia were not produced in chains. No chlamydospores were observed (3). Macroconidia in carnation leaf agar medium (2) were hyaline, 3 to 6 septate, mostly 4, falcate, with a distinct foot-like basal cell (2,3). DNA was amplified with primers ITS1/ITS4 and EF1/EF2 (3). Partial sequences of gene EF-1α showed 100% homology with F. temperatum (3) (GenBank Accession Nos. HM067687 and HM067688). DNA sequences of EF-1α gene and ITS region obtained were deposited in GenBank (KC179824, KC179825, KC179826, and KC179827). Pathogenicity of one representative isolate was confirmed using a soil inoculat