Kaur R, Rush T A, Ferrin D M, Aime M C
Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge 70803.
Plant Dis. 2011 Mar;95(3):353. doi: 10.1094/PDIS-03-10-0209.
Canna lily is a monocot, herbaceous perennial ornamental plant in the Cannaceae that is native to tropical South America and cultivated throughout the southern United States. Canna lily is a popular garden and landscaping plant and a large horticultural industry depends on this plant. In September 2008 and again in November 2009, two species of Canna lily (Canna × generalis L.H. Bailey and C. indica L.) were found to be severely infected with rust disease in three garden locations in southern Louisiana (East Baton Rouge Parish, Lafayette Parish, and Orleans Parish). Diseased samples from both host species and all locations exhibited similar symptoms of numerous, yellowish brown, subepidermal, erumpent, and irregular-shaped uredinia on both leaf surfaces. Initially, sori were scattered, later covering the entire leaf with coalescing pustules. Urediniospores were subglobose to ovoid or pyriform, echinulate, and measured 25.74 to 37.18 (-38.61) × 17.16 to 27.17 (-28.6) μm, with thickened apical walls, 1.3 to 1.6 μm, and one to two equatorial germ pores. Telia and teliospores were not observed on any of the collected samples. Pathogen identity was confirmed as Puccinia thaliae Dietel by nuclear ribosomal large subunit (28S) DNA sequencing with rust-specific primers (1). The sequence (deposited in GenBank as No. HQ434482), when blasted, was found to match sequence No. EU851154 of P. thaliae from C. indica with 98% identity (719 of 730 bp), the differences being attributed to a single insertion at bp 423 to 436 of sequence No. EU851154. The sequences of P. thaliae obtained from two different samples from Louisiana were identical and did not match any other sequence in GenBank. In North America P. thaliae is reported to cause rust on C. indica L. in Florida and C. × generalis in Texas, as well as on two members of the Marantaceae (Maranta arundinacea L. and Thalia geniculata L.) in Florida and M. arundinaceae in Mexico (2). To our knowledge, this is the first report of P. thaliae in Louisiana on Canna lily. Voucher materials (C. × generalis = LSU00123378 and C. indica = LSU00123384) have been deposited in the Bernard Lowy Mycological Herbarium (LSUM). References: (1) M. C. Aime. Mycoscience 47:112, 2006. (2) D. F. Farr and A.Y. Rossman. Fungal Databases. Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved 12 February from http://nt.ars-grin.gov/fungaldatabases/ , 2010.
美人蕉是单子叶植物纲、美人蕉科多年生草本观赏植物，原产于南美洲热带地区，在美国南部各地均有种植。美人蕉是一种受欢迎的园林和景观植物，庞大的园艺产业依赖于这种植物。2008年9月以及2009年11月，在路易斯安那州南部的三个园林地点（东巴吞鲁日教区、拉斐特教区和奥尔良教区）发现两种美人蕉（大花美人蕉Canna × generalis L.H. Bailey和美人蕉C. indica L.）严重感染锈病。来自两种寄主植物以及所有地点的患病样本在叶片两面均表现出相似症状，即有大量黄棕色、表皮下、隆起的不规则形状夏孢子堆。最初，孢子堆分散分布，后来聚合成脓疱覆盖整个叶片。夏孢子近球形至卵形或梨形，具刺，大小为25.74至37.18（-38.61）×17.16至27.17（-28.6）μm，顶端壁加厚，厚1.3至1.6μm，赤道处有一至两个芽孔。在所有采集的样本上均未观察到冬孢子堆和冬孢子。通过使用锈病特异性引物进行核糖体大亚基（28S）DNA测序，确认病原菌为塔利亚柄锈菌Puccinia thaliae Dietel（1）。该序列（在GenBank中登记号为HQ434482）进行比对时，发现与来自美人蕉的塔利亚柄锈菌序列EU851154有98%的同一性（730 bp中的719 bp），差异归因于EU851154序列第423至436 bp处的一个单碱基插入。从路易斯安那州两个不同样本中获得的塔利亚柄锈菌序列相同，且与GenBank中的任何其他序列均不匹配。在北美，据报道塔利亚柄锈菌可导致佛罗里达州的美人蕉C. indica L.和得克萨斯州的大花美人蕉C. × generalis感染锈病，以及佛罗里达州的竹芋科两种植物（竹芋Maranta arundinacea L.和竹叶蕉Thalia geniculata L.）和墨西哥的竹芋M. arundinaceae感染锈病（2）。据我们所知，这是路易斯安那州关于美人蕉上塔利亚柄锈菌的首次报道。凭证材料（大花美人蕉 = LSU00123378，美人蕉 = LSU00123384）已存于伯纳德·洛维真菌标本馆（LSUM）。参考文献：（1）M. C. Aime。《真菌科学》47:112，2006年。（2）D. F. Farr和A.Y. Rossman。《真菌数据库》。系统真菌学与微生物学实验室，美国农业部农业研究局。2010年2月12日从http://nt.ars-grin.gov/fungaldatabases/获取。
