Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/20892
標題: 立枯絲核菌第四融合群融合株之生理特性及致病性研究
Physiological characterization and pathogenicity of fusion clone F41 derived from Rhizoctonia solani AG-4 CHU 341 & CHU 344
作者: 余桂英
Yu, Kuei Ying
關鍵字: Rhizoctonia solani
立枯絲核菌
anastomosis group
RAPD
菌絲融合群
逢機增殖多型核酸
出版社: 植物學系
摘要: 中 文 摘 要 台灣地區之立枯絲核菌第四融合群 (Rhizoctonia solani AG-4),有些為強致病株,有些為弱致病株,而在強致病株中普遍 存在有分子量約為 2.6 kb 的線形質體 (linear plasmid)。為探討線形 質體與致病性之相關性,選取 R. solani AG-4 編號為 CHU 341 具有線 形質體之強致病株,與編號為 CHU 344 不具線形質體之弱致病株,進行 菌絲融合 (hyphal fusion)。並利用 Novozyme 234 分解細胞壁取得原生 質體,將原生質體再生培養後取得單一菌落,經由菌落外觀形態之觀察及 比較,篩選得到一菌落形態不同之菌株 (F41),抽取其 total DNA,發現 仍有線形質體存在。利用逢機增殖多型核酸 (RAPD, random amplified polymorphic DNA) 的方法分析其 total DNA,增殖後產物經洋菜凝膠電 泳分析,證實此菌同時具有兩母株之條帶 (bands),因此判定此菌為融合 株,但所出現之條帶以 CHU 341 佔多數。另外分離出 CHU 341 之質體 (pCHU341) 及染色體 DNA 進行 RAPD 分析,結果發現 pCHU341 所出現之 條帶與 CHU 341 重複,因此線形質體與 CHU 341 之染色體 DNA 具有同 源性 (homology)。以不同溫度 (℃) 及酸鹼值 (pH) 分析融合株 F41 之 生理特性及進行感病測試,並與原始母株做比較。結果顯示不同溫度及 pH 值對融合株 F41 之生長影響與 CHU 344 較相似,與 CHU 341 有較大 差異。而融合株之致病性則介於 CHU 341 與 CHU 344 間,由於融合株 F41 仍有質體存在,但致病性卻已明顯降低,因此推測線形質體與致病性 無關,而且 CHU 344 可能帶有抑病因子。
Abstract Rhizoctonia solani is a wide host range plant patho- genic fungus. Vegetative incompatibility among R. Solani strains are used to classify the fungi to be 11 anastomosis groups (AGs). Some specific strains carried plasmid(s), which belong to R. solani AG-4 from Taiwan, are more virulent in plants. CHU 341 and CHU 344 of R. solani AG-4 were used to make fusion clone by vegetative hyphal fusion; there CHU 341 carried plasmid is a virulent strain, and CHU 344 is a less virulent strain. One fusion clone F41 which carried a linear plasmid was identified. The phenotype of F41 is different from that of CHU 341 or CHU 344. Polymerase chain reaction (PCR)-based technology with random amplification of polymorphic DNA (RAPD) was use to assess the genomic variability among F41, CHU 341 and CHU 344. The result shows that the high level variability in RAPD fragments of F41 is similar to that of CHU 341, but the low in RAPD fragments of F41 is similar to that of CHU 344, it suggests that F41 is fusion clone of CHU 341 and CHU 344. In addition, the DNA plasmid in CHU 341 is homology to its chromosomal DNA. Physiological tests demonstrate that the F41 is similar to CHU 344, but different from CHU 341. Results of virulence assays revealed that the virulent of F41 is higher than that of CHU 344, but lower than that of CHU 341. The fact of F41 virulent decline that elicits that the plasmid does not carry pathogenic gene or factor for F41.
URI: http://hdl.handle.net/11455/20892
Appears in Collections:生命科學系所

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