First Report of Black Spot Caused by Colletotrichum gloeosporioides on Paper Mulberry in China.
First Report of Black Spot Caused by Colletotrichum gloeosporioides on Paper Mulberry in China.
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DOI：
10.1094/pdis-03-11-0186
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发表时间：
2011-06
期刊：
影响因子：
4.5
通讯作者：
J. Yan;P. Wu;H. Du;Q. Zhang
中科院分区：
文献类型：
--
作者：
J. Yan;P. Wu;H. Du;Q. Zhang
纸桑(Broussonetia Papyrifera(L.)文腾。(桑科)，是一种生长迅速的树木，枝叶繁茂。由于具有较强的适应性和对不利环境条件的耐受性，它是矿区和山坡上遮荫、遮荫和造林的重要树种。2010年夏季，在北京白望山森林公园，观察到纸桑叶片上出现了褐变到黑斑。早期症状为圆形或椭圆形，淡棕色，小病灶扩展至圆形或不规则斑点(4~6×4~8 mm)，中心呈深棕色或黑色，边缘为棕色或淡棕色。在严重感染的叶片上发现了几十个斑点。从病斑边缘切下2×2 mm的叶片组织，用0.5%NaOCl溶液表面消毒3min，用无菌水漂洗3次，涂在马铃薯葡萄糖琼脂(PDA)上，在25℃下孵育，光照12h，黑暗12h。3天后可见大量蜡状真皮下尖锐湿疣，并有刚毛。顶端为棕色或黑色，圆形或细长，直径100~250μm。刚毛深褐色，直立或稍弯曲，60~74×4~8μm，具1~2个隔膜。分生孢子柄呈透明或淡棕色，短无分枝，圆柱形，大小为12~21×4~5μm，分生孢子11~21×3~6μm，透明，无柄，圆柱形。PDA上的菌丝在菌落反面呈白色到深灰色。从不同病叶中分离到6个菌株(BP21-1~BP21-6)，经鉴定为胶孢炭疽菌(Colletotrichum Gloeosporioides(Penz.)彭兹。&Sacc.(丝形藻Glmerella cingulata(Stonem.)Spaulding&Schrenk)，根据反向菌落颜色、无柄、分生孢子梗和分生孢子的大小和颜色(3)。对6株分离株进行ITS1-5.8S-ITS2 rDNA序列分析。所得序列完全相同(GenBank登录号：HQ 654780)，与GenBank(登录号：EU371022.1和AY376532.1)(2)中的胶状芽孢杆菌同源性为99%(100%)。用6株3个月龄的盆栽纸桑进行致病性测定。BP21-2菌株在PDA上培养14天，分生孢子制成106孢子/毫升的悬浮液，其中3株喷洒分生孢子悬浮液，3株喷洒无菌水。所有树木用塑料袋覆盖24小时以保持高湿度，并在25℃下孵化6天。所有接种分生孢子的树木表现出与园区感染叶片相同的症状，而对照树木则保持无症状。对该真菌的重新分离证实，其病原菌为球囊孢子菌。球孢霉在世界范围内分布广泛，引起包括桑科桑科植物在内的多种植物上的炭疽病，如桑树(Morus alba L.)茎插条死亡和幼树死亡。在印度(1)。据了解，这是中国地区首次报道炭疽菌引起纸桑黑斑病。参考文献：(1)V.P.Gupta等人。印度植物病原体。1997年，50：402。(2)K.D.海德等人。真菌潜水员。2009年，39：147。(3)J.E.M.莫杜。第315号：病原真菌和细菌的描述。CMI。英国萨里郡邱郡，1971年。
Paper mulberry, Broussonetia papyrifera (L.) Venten. (family Moraceae), is a fast-growing tree with luxuriant branches and leaves. Because of strong adaptability and tolerance to unfavorable environmental conditions, it is an important tree species for shade or shelter and reforestation in mined areas and on hillsides. During the summer of 2010, brown-to-black spots were observed on leaves of paper mulberry in Baiwangshan Forest Park in Beijing, China. Early symptoms were round or elliptic, light brown, small lesions that later extended to round or irregular spots (4 to 6 × 4 to 8 mm) that were dark brown or black in the center with brown or light brown margins. Several dozen spots were found on severely infected leaves. Leaf tissues (2 × 2 mm), cut from the margins of lesions, were surface disinfected in 0.5% NaOCl solution for 3 min, rinsed three times with sterile water, plated on potato dextrose agar (PDA) and incubated at 25°C with a 12-h light and 12-h dark period. Numerous waxy subepidermal acervuli with setae were observed after 3 days. Acervuli were brown or black, round or elongate, and 100 to 250 μm in diameter. Setae were dark brown, erect straight or slightly curved, and 60 to 74 × 4 to 8 μm with one to two septa. Conidiophores were hyaline or light brown, short with no branches, and cylindrical with dimensions of 12 to 21 × 4 to 5 μm. Conidia were 11 to 21 × 3 to 6 μm, hyaline, aseptate, and cylindrical. Mycelia on PDA were off white-to-dark gray on the reverse side of the colony. Six isolates (BP21-1 to BP21-6) were obtained from different infected leaves and identified as Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. (teleomorph Glomerella cingulata (Stonem.) Spaulding & Schrenk) on the basis of reverse colony color, dimensions and colors of acervuli, conidiophores, and conidia (3). ITS1-5.8S-ITS2 rDNA sequence analysis was performed on all six isolates. The resultant sequences were identical (GenBank Accession No. HQ 654780) and revealed 99% similarity (100% coverage) with C. gloeosporioides isolates in the GenBank (Accession Nos. EU371022.1 and AY376532.1) (2). Pathogenicity was demonstrated using six potted 3-month-old paper mulberry trees. Isolate BP21-2 was grown on PDA for 14 days and conidia were harvested to prepare a suspension of 106 conidia/ml. Three plants were sprayed with the conidial suspension and three were sprayed with sterile water. All trees were covered with plastic bags for 24 h to maintain high humidity and incubated at 25°C for 6 days. All conidia-inoculated trees showed identical symptoms as the infected leaves in the park, while the control trees remained symptom free. Reisolation of the fungus confirmed that the causal agent was C. gloeosporioides. C. gloeosporioides is distributed worldwide causing anthracnose on a wide variety of plants including members of mulberry family Moraceae, e.g., mortality of stem cuttings and death of saplings on mulberry (Morus alba L.) in India (1). To our knowledge, this is the first report of C. gloeosporioides causing black spots on paper mulberry in China. References: (1) V. P. Gupta et al. Indian Phytopathol. 50:402, 1997. (2) K. D. Hyde et al. Fungal Divers. 39:147, 2009. (3) J. E. M. Mordue. No. 315 in: Descriptions of Pathogenic Fungi and Bacteria. CMI. Kew, Surrey, UK, 1971.