水稻雲紋葉枯病菌生理、毒質與生物防治之研究

Study on physiology, phytotoxins and biocontrol of Monographella albescens

廖慶燿(Yao-Ching Liao)

指導教授 ： 羅朝村

國立虎尾科技大學/電機資訊學院/光電與材料科技研究所/碩士(2011年)

https://doi.org/10.6827/NFU.2011.00057

摘要

由Monographella albescens 引起之水稻雲紋葉枯病（rice leaf scald）為臺灣新興的一種水稻病害，被記載主要分佈於台東及高雄地區。本研究之病原菌株是從有雲紋葉枯病徵之高雄139 號水稻病葉上分離出之RL-1 菌株，此病原菌菌絲於PDA 培養基上形態為不規則放射狀，具橙紅色色素且，外圍具有白色氣生菌絲;分生孢子無色透明，多為短新月形或透明橢圓，兩端漸細大多為1-2 隔膜，少部份具3 隔膜，孢子量測平均大小為11.94–14.8 μm × 2.62–4.24 μm，確認此菌株為Monographella albescens。再以柯霍氏法則回接到水稻台稉9 號葉面，產生相同之病徵，並經病班處再分離出相同菌株，確認其具有病原性。經測試各種生理試驗顯示M. albescens 以20-24 ℃為最適生長溫度; 最佳碳源為棉實糖及蔗糖; 氮源則以蛋白腖及硝酸鈣生長最佳;最適C/N ratio 為約在20; 最適生長pH 值為5.6~6.0; 孢子發芽率在20-24 ℃達60-80 %。在測試的水稻品種中，台稉9 號耐病最好，其次為台農71 號與145 號。將M. albescens 培養於PSB 培養基後，過濾液可造成水稻葉片呈現類似病徵，經進一步分離純化與鑑定，獲得兩個化合物albescensamide A 與albescenamide B 。其中以albescenamide B 可以對水稻台稉9 號葉片引起黃化病徵之生物活性。在病害防治上，初步利用木黴菌屬與枯草桿菌在培養基上均能有效抑制病原菌生長; 進而作溫室測試，以枯草桿菌菌液稀釋50 倍後，連續噴灑七日於罹病水稻秧苗葉片上，顯示菌株Bs9 與Bs10 不但能有效抑制病害且同時可促進作物生長。

關鍵字

雲紋葉枯病 ； 黃化病徵 ； 生物防治

並列摘要

Rice leaf scald of Monographella albescens is a new and serious disease in southeastern area of Taiwan. The isolation of infective pathogen from rice leaf Kaohsiung No. 139 has been reported in 2009. The pathogen isolated in this laboratory shared the reported morphological characters of M. albescens that are white cotton shape with colorless sickle shaped to oblong apedicellate, and 11.94 – 14.8 μm × 4.24 – 2.62 μm size of the conidia. Conidia of the fungus, mostly, is unicellular or bicellular but rarely multicelluar. The isolate RL-1 showed typical symptoms on the rice cutlivars, when inoculated on rice leaves. The growth conditions are 8 to 32 oC with optima 20 to 24 oC in temperature and pH 4 to 8 with optima pH 5.6 to 6.0. In nutrients requirements, melitose and sucrose are the best among 14 tested carbon source and peptone and calcium nitrate among 21 tested nitrogen sources that gave optima C/N ratio of 20 to 80. The molecules related to the pathogenicity of M. albescens were obtained from the liquid culture media after serious chromatographs along with pathogenesis oriented assay. The structures of the two small molecules were determined by the NMR and dubbed albescenamide A and albescenamide B with mass of A 287 da. and B 357 da. B molecules is a new compound and firstly reported in this research. The albescenamide B, but not the albescenamide A, might contribute the part of pathogenicity of the M. albescens because Albescenamide B treated rice leaf showed the yellow symptom of M. albescens.During the period of heading stage and spraying spore (105 conidia /ml), after the seeds turn into mature and we can collect and sow that we can found hazard of plants. The cultivars of rice Tai-keng No.9, Tai-nung No. 71 and Kaohsiung No. 145 was tested to determine the disease-resistance testing that shows Tai-keng No.9 between than other two types of even more resistance to the disease.the filtrates of M. albescens cultured in PSB medium caused similar symptoms on rice leaves. Many applications biocontrol of plant pathogenic antagonistic, Trichoderma harzianum and Bacillus subtilis strain 9 and strain 10 inhibited mycelial growth of M.albescens on PDA medium. Morevens, suppression of 50x dilution filtrate to Bs-9 and Bs-10 on seedling leaf scald as seedling with daily spray application were found during culture stages.

並列關鍵字

Rice leaf scald ； Monographella albescens ； phytotoxin ； biocontrol

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