- 期刊
＂Xanthomonas oryzae pv. oryzicola＂引起的水稻細菌性條斑病
Bacterial Leaf Streak of Rice Caused by ＂Xanthomonas oryzae＂ pv. ＂oryzicola＂ (Fang et al.) Swings et al. in Taiwan
摘要
2007年在南投縣草屯鎮及雲林縣二崙鄉田區水稻陸續出現暗綠色至黃褐色條斑的病徵，條斑上有時可見細小的黃色菌泥，後來陸續在苗栗、台中、彰化、嘉義、台南、花蓮和台東等地發現相同的病徵，從條斑處可分離出黃色細菌，菌落型態類似白葉枯病菌，經柯霍氏法確定此黃色細菌為病原，經過16S rDNA定序比對，結果顯示此病原細菌與水稻白葉枯病菌Xanthomonas oryzae pv. oryzae（Xoo）相似度高達97%，與Xanthomonas oryzae pv. oryzicola（Xoc）相似度達100%，此病原細菌接種至供試水稻品種上皆造成條斑狀病徵，不同於白葉枯病菌造成的典型葉枯型病徵，且生理生化試驗測定結果得知該細菌可利用L-Alanine，但無法生長在含有Cu(NO_3)_2的培養基中，確認該病原細菌為X. oryzae pv. oryzicola，可引起水稻細菌性條斑病。又於溫室接種不同水稻品種測試其抗感病性程度，結果顯示16個台灣常見品種均可感病，但3個供試菌株造成的發病程度不一，XOCH-1菌株（平均罹病等級為1.8）致病力明顯較XOCI-1c（2.3）及XOCK-1b（3.1）弱。「台稉2號」、「台稉8號」、「台稉11號」、「台稉16號」和「台南11號」發病率均達100%，「台南11號」和「台稉16號」平均罹病等級最高（3.6和3.3）；發病率最低者分別為「高雄145號」（41.7%）、「台東30號」（41.7%）和「台稉糯1號」（78.3%）。測試10種殺菌劑在不同濃度下對該病菌的生長抑制效果，以81.3%嘉賜銅可濕性粉劑400×、80%鋅錳乃浦可濕性粉劑1,000×，以及白葉枯病防治藥劑10%鏈四環黴素可濕性粉劑1,000×、10%克枯爛可濕性粉劑1,000×的效果最佳，將其稀釋液於溫室內進行防治試驗，結果顯示4種藥劑均能降低發病率，且接種前施用較接種後施用防治效果佳，其中以接種前3天施用鋅錳乃浦、接種前7天及前1天施用嘉賜銅的防治效果最佳。
並列摘要
In 2007, a new disease of rice was found in Nantou and Yunlin Counties in Taiwan. The symptoms exhibited dark-green to light brown translucent streak on rice leaf, and bacterial oozes appear on the lesions under humid conditions. This disease was later found in Miaoli, Taichung, Changhua, Chyayi, Tainan, Huailien, and Taitung Counties in Taiwan. Results from 16S rDNA sequencing and comparison revealed that the nucleotide sequences shared 97% similarity with the ones of ＂Xanthomonas oryzae pv.＂ oryzae (Xoo), and 100% similarity with ＂Xanthomonas oryzae pv. oryzicola＂ BLS256. Based on the symptoms and pathological studies, 16S rDNA sequencing, and physiological and biochemical analyses, the pathogen was identified as ＂Xanthomonas oryzae pv. oryzicola＂ (Xoc). The susceptibility of rice cultivars to bacterial leaf streak (BLS) were tested in greenhouse. Sixteen rice cultivars were susceptible, but the disease incidence and index were different when inoculating with different Xoc strains. The virulence of Xoc strains XOCH-1 (disease index was 1.8) was lower than XOCI-1c (2.3) and XOCK-1b (3.1). The disease incidence of rice cultivars 'Taikeng 2', 'Taikeng 8', 'Taikeng 11', 'Taikeng 16' and 'Tainan 11' were 100%. Among them, the highest disease index was 3.6 for 'Tainan 11' and was 3.3 for 'Taikeng 16'. The disease incidence of 'Kaohsiung 145' (41.7%), 'Taitung 30' (41.7%) and 'Taikeng glutinous 1' (78.3%) were lower than the other thirteen cultivars. Besides, ten commercial agrochemicals were tested and results showed that they can almost inhibit the growth of all tested Xoc strains. Among those, four agrochemicals could control BLS disease in greenhouse, especially spraying Mancozeb and Kasugamycin + Copper oxychloride before inoculation.