CAJ | 학술논문

为分析河南省某育苗基地西瓜幼苗大量死亡的病因，从感病植株根部组织上分离、纯化得到病原物K1，经培养性状、形态特征观察，初步鉴定为尖孢镰孢菌（Fusarium oxysporum）。对该病原菌ITS rDNA、EF 1α和M tSSU等序列进行分析发现，均与枯萎型尖孢镰刀菌高度同源，同源性达99％。病原物致病性及寄主专化型测定显示，西瓜幼苗接种该菌后表现出枯萎病症状，与采集地自然发病株症状基本一致；与不同瓜类如甜瓜和黄瓜比较，该病原在西瓜上发病较为严重。综上分析，此例河南西瓜死苗现象是由枯萎型尖孢镰孢菌西瓜专化型（Fusarium oxyporum f ．sp ． niveum）侵染引起。
위분석하남성모육묘기지서과유묘대량사망적병인，종감병식주근부조직상분리、순화득도병원물K1，경배양성상、형태특정관찰，초보감정위첨포렴포균（Fusarium oxysporum）。대해병원균ITS rDNA、EF 1α화M tSSU등서렬진행분석발현，균여고위형첨포렴도균고도동원，동원성체99％。병원물치병성급기주전화형측정현시，서과유묘접충해균후표현출고위병증상，여채집지자연발병주증상기본일치；여불동과류여첨과화황과비교，해병원재서과상발병교위엄중。종상분석，차례하남서과사묘현상시유고위형첨포렴포균서과전화형（Fusarium oxyporum f ．sp ． niveum）침염인기。
To analyze the pathogen causing a large number of watermelon seedlings death in a breeding base of Henan province ,the fungus was isolated and purified from diseased root tissues , which was primarily identified as Fusarium oxysporum based on the cultural features and mor-phological characteristics .Through the study of DNA sequence of ITS-rDNA ,EF-1α and MtSSU of Fusarium ,these DNA sequences of the isolate were 99% homologous with the other corre-sponding sequences of Fusarium oxysporum causing wilt disease of plants in GenBank .The pathogenicity and host biotype were further tested ,which showed that inoculated watermelon seedlings with this isolate could produce the same symptoms as naturally infected plants ,and this isolate was more virulent to watermelon seedling than to other tested cucurbits ,such as melon and cucumber .In short ,all these results confirmed that the causal agent of watermelon seedlings death was Fusarium oxyporum f .sp .niveum ,specialization of the watermelon .