新穎材料農業：農業新穎材料在植物保健開發、應用與機理【植物病理學系/王智立副教授/優聘教師】
| 論文篇名 | 英文：First report of Septoria blotch of passion fruit caused by Septoria passifloricola in Taiwan 中文：由Septoria passifloricola引起之百香果白星病於台灣的首次報導 |
| 期刊名稱 | Plant Disease |
| 發表年份,卷數,起迄頁數 | 2021, 105, 700 |
| 作者 | Dai, Yu-Lun; Wang, Ching-Chung; Lin, Huey-Ling(林慧玲); Wang, Chih-Li(王智立)* |
| DOI | 10.1094/PDIS-07-20-1571-PDN |
| 中文摘要 | 百香果起源於南美洲，在熱帶和亞熱帶國家種植，用於新鮮市場和果汁加工。在台灣，每年都會使用健康的百香果嫁接苗進行種植，以盡量減少病毒的影響。常用的嫁接苗以紫百香果‘台農一號’（PPF，Passiflora edulis × Passiflora edulis forma flavicarpa）為接穗，黃百香果（YPF，P. edulis f. flavicarpa）為砧木。 2016年7月和2018年5月，台中市和南投縣株齡2～3月的百香果嫁接苗出現新的百香果葉斑病。在商業溫室苗圃中，大約 17% 的幼苗在葉子上出現症狀。受感染的葉子較早脫落，導致嫁接幼苗的存活率降低。 在YPF和PPF上葉片病斑為圓形至不規則，呈白灰色或淺棕色，周圍有深綠色邊緣和明顯的褪綠光暈。病斑中心形成真菌分生孢子殼，在高濕度下擠出長長的黃白色分生孢子堆。通過單孢子分離獲得假定的真菌病原菌。在馬鈴薯葡萄糖瓊脂上獲得了6株分離株，分離自2個地理區域，皆具有相似形態特徵。為了確認病原性，將分離株 PLS-S2的分生孢子懸浮液（107 分生孢子 / ml）10 μl滴在完整或具傷口的YPF 幼苗葉背。每處理3株植物，每株植物接種4片葉子，接種的植物在高濕度的塑膠袋中保存濕3 天，並在 24°C 的走入式生長室中生長，光照條件為 每日12 小時。最初的病徵是點狀病斑，後來擴大為圓形的壞死斑點，周圍有黃色暈環，類似於商業溫室苗圃中的病徵。在接種後 28 天 (dpi)，完整葉上約 44% 的接種點 (n = 48) 出現病徵，傷口葉片上100%的 接種點 (n = 72) 在 21 dpi 時出現病徵。處理水的對照組在葉片上沒有發生病斑。從這些病徵中重新分離的病原菌在形態上與接種的真菌相同。分生孢子是透明的，絲狀到圓柱形，有 1 - 3 個隔膜，大部分為 9 - 30 × 1.0 - 2.3 μm。分離株的形態特徵與Septoria passifloricola Punith 相似。分子鑑定基於部分 TEF1-α 基因（登錄號 MK643056 至 MK643061）和 β-微管蛋白基因（登錄號 MK643050 至 MK643055）的串聯序列。 BLAST 搜索顯示菌株 PLS-S2 與S. passifloricola CBS 129431 的 TEF1-α 基因 (KF253443.1) 具有 100.0% 相同 (392 bp) ，β-微管蛋白基因 (KF25296 .1）有98.4% 相同 (311 bp)。親源分析指出，PLS-S2 和另外5個分離株與 S. passifloricola 參考菌株聚集在一個可靠的演化支序中（95% bootstrap value）。結果表明台灣百香果葉斑病是由S. passifloricola引起的。此病害已在非洲、印度、澳大利亞、新西蘭、加勒比和南美洲有報告。如果不採取適當的控制措施，該病害可能成為台灣苗圃的主要葉部病害。 |
| 英文摘要 | Passion fruit originated in South America and is cultivated in tropical and subtropical countries for the fresh market and juice processing. In Taiwan, healthy grafted seedlings of passion fruit have been used for replanting every year to minimize the impact of viral and root diseases. The grafted seedlings commonly used are purple passion fruit ‘Tainung NO.1’ (PPF, Passiflora edulis × Passiflora edulis forma flavicarpa) as scion and yellow passion fruit (YPF, P. edulis f. flavicarpa) as rootstock. In July 2016 and May 2018, a new leaf disease of passion fruit was observed in Taichung City and Nantou County on 2- to 3-month-old grafted passion fruit seedlings. About 17% of seedlings showed symptoms on leaves in a commercial greenhouse nursery. The infected leaves abscised earlier, causing reduced survival of grafted seedlings. The leaf lesions on YPF and PPF were round to irregular and white-grayish or light brown, and they were surrounded by dark green borders and obvious chlorotic halos. Fungal pycnidia were formed in the center of lesions and extruded long yellow-white conidial tendrils under high humidity. The presumed fungal pathogens were obtained by single-spore isolation. Six isolates from the two geographic regions with similar morphological characteristics on potato dextrose agar were obtained. To confirm the pathogenicity, YPF seedlings were inoculated by dropping 10 μl of a conidial suspension of isolate PLS-S2 (107 conidia/ml) on each inoculation site located on abaxial leaf surfaces that were either intact or wounded to form three pinpricks in a 4-mm area with a sterilized needle. Three plants were used in a treatment, and four leaves of each plant were inoculated. The inoculated plants were kept in plastic bags with high humidity for 3 days and grown in a walk-in growth chamber at 24°C with a 12-h light regime. The initial symptoms were punctate lesions that later enlarged to round, necrotic spots surrounded by yellow halos, which resembled symptoms in commercial greenhouse nurseries. About 44% of inoculation sites (n = 48) on intact leaves developed lesions at 28 days postinoculation (dpi), and 100% of inoculation sites (n = 72) on wounded leaves showed lesions at 21 dpi. No lesions developed on leaves with the water control. Pathogens reisolated from these lesions were morphologically identical to the inoculated fungus. Conidia were hyaline, filiform to cylindrical with one to three nonconstricted septa, and mostly 9 to 30 × 1.0 to 2.3 μm. The morphological characteristics of the isolates were similar to Septoria passifloricola Punith. Molecular identification was based on concatenated sequences of partial TEF1-α gene (accession nos. MK643056 to MK643061) and β-tubulin gene (accession nos. MK643050 to MK643055) for each of the six isolates. The BLAST search revealed that strain PLS-S2 was 100.0% identical (392 bp) to S. passifloricola CBS 129431 for the TEF1-α gene (KF253443.1) and 98.4% identical (311 bp) for the β-tubulin gene (KF252964.1). Phylogenetic analysis showed that PLS-S2 and five additional isolates clustered with reference strains of S. passifloricola in a well-supported clade (95% bootstrap value). Results suggested that the leaf disease of passion fruit in Taiwan was caused by S. passifloricola. This disease has been reported in Africa, India, Australia, New Zealand, the Caribbean, and South America. If appropriate control actions are not taken, the disease may become a major leaf disease in nurseries in Taiwan. |
| 發表成果與本中心研究主題相關性 | 2016年南投、台中 商業生產的百香果嫁接苗出現新的葉部病害，本研究完成科霍氏法則證明造成病害的病因，並以形態及分子特徵釐清病原菌的種類，證明為台灣首次記錄的病害。研究成果有助於尋求田間的病害管理策略，使百香果產業得以永續發展。 |
