臺灣博碩士論文加值系統

立枯絲核菌(Rhizoctonia solani Kn)為本省重要的植物病原真菌，能
感染的寄主種類廣泛。R. solani第四融合群(anastomosis group 4,簡稱
AG-4)編號為CHU341之強致病株具有一約2.6 Kb之線形質體；編號CHU344
之弱致病株則不具有線形質體；而R. solani CHU344+pUCH1-ES是經轉形
作用所得的穩定轉形株。本研究以此三株菌來探討生長條件、致病性與線
形質體的關聯。強致病株CHU341對於不同的碳、氮源之適應良好，而弱致
病株CHU344及轉形株CHU344+pUCH1-ES則對養份的利用性較CHU341為差。
在溫度及酸鹼度方面，皆具有一般立枯絲核菌之生理特性，最適生長於27
℃及pH 6-7之環境下。且轉形株之生理特性與弱致病性之原始母株CHU344
相似。利用其對營養、溫度、酸鹼度之適應性不同，可加以運用於菌株篩
選及生物防治上。轉形株CHU344+pUCH1-ES對蘿蔔植株的感病性及交叉保
護皆介於CHU341及CHU344菌株之間。且蘿蔔植株經轉形株CHU344+pUCH1-
ES誘導的幾丁質酵素活性亦呈類似的變化。因此推測線形質體可能與致病
性及幾丁質酵素有關。

In Taiwan, Rhizoctonia solani Kuehnn is an important plant
pathogenic fungus. It possesses a wide host range. A strong
pathogenic strain CHU341 which belongs to anastomosis group 4
(AG-4) carries a linear plasmid about the size of 2.6 Kb.
Another strain CHU344 is a weak pathology without linear
plasmid. The other stable transformant CHU344+pUCH1-ES was
obtained from CHU341 and CHU344. This study analyzed the
relationship between R. solai linear plasmid and growth
conditions as well as their pathogenecity.The strong pathogenic
strain CHU341 is well adapted to carbon source and nitrogen
source. The weakly pathogenic strain CHU344 and the transformant
CHU344+pUCH1-ES are sensitive of carbon and nitrogen sources.
The optimal temperatures and pH-values for the growth of R.
solani strains are 27℃ and pH 6-7. The physiological
characteristics of transfor-mant are similar to that of the
weakly pathogenic strain CHU344. The results of the growth
condition tests could be used for the biological control and
selection of R. solani strains. The pathogenecity for radish of
the transformant was between CHU341 and CHU344, and the radish's
chitinase induced by the transformant had similar relation. The
above results suggested that the linear plasmid of R. solani may
consist a relationship with pathogenecity and the linear plasmid
as well as induction of chitinase.