CAJ | 학술논문

由尖镰孢古巴专化型(Fusarium oxysporum f. sp. cubense, Foc)引起的香蕉枯萎病是香蕉生产中的毁灭性病害之一。Foc有4个小种，其中4号小种(Focr4)因其寄主范围广且无高抗病性的香蕉品种，对香蕉产业的危害最大，其致病机制至今尚不清楚。为研究其致病机制，本文对Focr4野生型菌株(Focr4-193-6)、因其T-DNA插入导致致病性严重减弱的突变体Focr4-1701、T-DNA插入标签基因敲除子△Focr4-1701及敲除基因互补子吟Focr4-1701-cp-1为材料，从致病性测定、玻璃纸穿透试验、孢子形态观察、产孢量与孢子萌发率测定、粗毒素测定等方面对其与致病性相关的生物学表型进行了测定。结果表明：T-DNA插入突变体Focr4-1701和基因敲除突变体吟Focr4-1701接种后的香蕉植株叶片没有表现发病症状，敲除基因互补菌株与野生型菌株一样表现出发病症状；T-DNA插入突变体和基因敲除突变体不能穿透玻璃纸生长，T-DNA插入突变体及基因敲除突变体在产孢量、孢子萌发率和产毒素能力上均极显著低于野生型菌株及互补菌株。这些表型性状差异说明Focr4-1701致病性严重减弱可能是T-DNA插入位点标签基因失活后导致了菌丝体侵染能力下降及产毒素能力降低造成的。
유첨렴포고파전화형(Fusarium oxysporum f. sp. cubense, Foc)인기적향초고위병시향초생산중적훼멸성병해지일。Foc유4개소충，기중4호소충(Focr4)인기기주범위엄차무고항병성적향초품충，대향초산업적위해최대，기치병궤제지금상불청초。위연구기치병궤제，본문대Focr4야생형균주(Focr4-193-6)、인기T-DNA삽입도치치병성엄중감약적돌변체Focr4-1701、T-DNA삽입표첨기인고제자△Focr4-1701급고제기인호보자음Focr4-1701-cp-1위재료，종치병성측정、파리지천투시험、포자형태관찰、산포량여포자맹발솔측정、조독소측정등방면대기여치병성상관적생물학표형진행료측정。결과표명：T-DNA삽입돌변체Focr4-1701화기인고제돌변체음Focr4-1701접충후적향초식주협편몰유표현발병증상，고제기인호보균주여야생형균주일양표현출발병증상；T-DNA삽입돌변체화기인고제돌변체불능천투파리지생장，T-DNA삽입돌변체급기인고제돌변체재산포량、포자맹발솔화산독소능력상균겁현저저우야생형균주급호보균주。저사표형성상차이설명Focr4-1701치병성엄중감약가능시T-DNA삽입위점표첨기인실활후도치료균사체침염능력하강급산독소능력강저조성적。
Fusarium wilt of banana caused by Fusarium oxysporum f. sp. cubense (Foc) is a devastating disease in banana production. Among 4 races of Foc, the race 4 (Focr4) causes the greatest damage due to its wide host range,and the absence of highly resistant banana varieties. To date, the pathogenic mechanism of Foc4 is mostly unknown. In this study, a comparative study of the biological characteristic of the wild strain Focr4-193-6, the T-DNA inserted mutant strain Focr4-1701, the gene-knockout mutant strain (△Focr4-1701) and the complemen-tary mutant strain (△Focr4-1701-cp-1) was performed, and the relationships between the pathogenicity and the mutant gene due to the T-DNA inserted were elucidated. The results showed that no obvious disease symptoms were observed on the leaves of the banana plants inoculated with the T-DNA inserted mutant strain Focr4-1701 and the gene-knockout mutant strain△Focr4-1701. On the other hand, plants inoculated with Focr4-193-6 and△Focr4-1701-cp-1 showed distinct disease symptoms. Both Focr4-1701 and△Focr4-1701 could not penetrate the cellophane to initate growth. The spore germination rate spore yield and toxin-producing ability of Focr4-1701 and △Focr4-1701 were significantly lower than those of the other two types of strains. The activities of pectin methyl-galacturonase (PMG) and pectin methyl transeliminase (PMTE) produced by Focr4-1701 and△Focr4-1701 were also less than those of△Focr4-1701-cp-1 and Focr4-193-6. These phenotypic differences indicated to the reduction in the infection and toxin-producing abilityes of the inactivated strain obtained by T-DNA insertion.