甜瓜种子携带的镰刀菌种类鉴定及其致病性研究

 采用洗涤检验法和马铃薯葡萄糖琼脂培养基法,从甜瓜种子上分离得到23个镰刀菌分离物。采用形态观察和分子生物学方法对其进行鉴定,并研究其致病性以及对甜瓜种子发芽的影响。通过观察菌落形态和色素颜色,以及大型分生孢子、小型分生孢子和厚垣孢子形态,同时分析ITS-rDNA序列和翻译延伸因子-1α(TEF-1α)基因序列,以确定真菌分离物的分类属性。结果表明,4个分离物为尖孢镰刀菌(Fusarium oxysporum),5个分离物为层生镰刀菌(F. proliferatum),5个分离物为木贼镰刀菌(F. equiseti),9个分离物为轮枝样镰刀菌(F. verticillioides)。这4种镰刀菌均对甜瓜幼苗有致病性,其分生孢子悬浮液对甜瓜种子发芽有抑制作用。这是我国首例开展甜瓜种子携带致病性镰刀菌的研究报道。

Studies on taxonomic identity and pathogenicity of Fusarium spp. associated with muskmelon seeds

Twenty three Fusarium isolates obtained from muskmelon seeds using water washing and potato dextrose agar (PDA) plating methods were identified by morphological observation (colonies, color of pigment, morphology of macroconidia, microconidia, and chlamydospores) and molecular characterization (analysis of the DNA sequences of ITS-rDNA and the translation elongation factor 1α gene). Pathogenicity on the muskmelon seedlings and the effect on the seed germination of these Fusarium isolates were also studied. The results showed that four isolates belonged to Fusarium oxysporum, five isolates belonged to F. proliferatum, five isolates belonged to F. equiseti, and nine isolates belonged to F. verticillioides. All of the four Fusarium species were pathogenic to muskmelon seedlings. The conidia produced by these species showed an inhibitory effect on muskmelon seed germination. To our knowledge, this is the first detailed report about species identification and pathogenicity tests of Fusarium spp. associated with muskmelon seeds in China.