Karugia G W, Suga H, Gale L R, Nakajima T, Tomimura K, Hyakumachi M
United Graduate School of Agricultural Sciences, Gifu University Yanagido 1-1, Gifu 501-1193, Japan.
Life Science Research Centre, Gifu University, Yanagido 1-1, Gifu 501-1193, Japan.
Plant Dis. 2009 Feb;93(2):170-174. doi: 10.1094/PDIS-93-2-0170.
The Fusarium graminearum species complex (Fg complex) that consists of at least 11 phylogenetically distinct species contains important Fusarium head blight (FHB) pathogens of wheat and barley worldwide. We obtained members of the Fg complex by sampling from a 500-m experimental wheat field in Kumamoto Prefecture, Japan in two consecutive years and assessed them for species identity and trichothecene chemotype. Haplotype diversity was estimated by using 11 variable numbers of tandem repeat (VNTR) markers. In addition to these two samples (group 03W in 2003 and group 04W in 2004), pathogen populations from seed that was harvested in Fukuoka Prefecture and planted in the experimental field in 2002 (group 02WSC) and pathogen populations from seed that was harvested in Nagasaki Prefecture and planted in 2003 (group 03WSC) were analyzed for this study. Forty-six isolates were collected in each group. Most isolates from wheat heads were classified as F. asiaticum; only four isolates were classified as F. graminearum sensu stricto (s. str.). Out of a total of 183 Fg complex strains, 80 isolates (44%) were of the NIV type, while 103 isolates (56%), including all four F. graminearum s. str. isolates, were of the 3ADON type. No 15ADON type isolate was detected in this study. Trichothecene chemotype compositions of 03W and 04W were nearly identical. High gene diversity of F. asiaticum was observed in all groups. Based on the observed low level of fixation index (F) and high level of effective number of migrants (Nm), distinctive population subdivision of F. asiaticum was not inferred among the four groups. These results suggest that FHB in the experimental wheat field in both 2003 and 2004 was caused by a genetically similar population, which prevails in Kumamoto, Fukuoka, and Nagasaki prefectures.
禾谷镰刀菌复合种（Fg复合种）由至少11个系统发育上不同的物种组成，包含全球范围内小麦和大麦重要的赤霉病（FHB）病原菌。我们连续两年从日本熊本县一块500米的实验小麦田中采样获得Fg复合种的成员，并对其进行物种鉴定和单端孢霉烯化学型评估。通过使用11个可变串联重复序列（VNTR）标记估计单倍型多样性。除了这两个样本（2003年的03W组和2004年的04W组），本研究还分析了2002年在福冈县收获并种植于实验田的种子中的病原菌群体（02WSC组）以及2003年在长崎县收获并种植的种子中的病原菌群体（03WSC组）。每组收集了46个分离株。从小麦穗上分离得到的大多数菌株被归类为亚洲镰刀菌；只有4个菌株被归类为狭义禾谷镰刀菌（F. graminearum sensu stricto，s. str.）。在总共183个Fg复合种菌株中，80个分离株（44%）为NIV型，而103个分离株（56%），包括所有4个狭义禾谷镰刀菌分离株，为3ADON型。本研究未检测到15ADON型分离株。03W和04W的单端孢霉烯化学型组成几乎相同。在所有组中均观察到亚洲镰刀菌的高基因多样性。基于观察到的低固定指数（F）和高迁移有效数（Nm），未推断出亚洲镰刀菌在这四个组之间存在明显的种群细分。这些结果表明，2003年和2004年实验小麦田中的赤霉病是由遗传上相似的群体引起的，该群体在熊本、福冈和长崎县普遍存在。
