First Report of Brown Rot on Crataegus pinnatifida var. major Caused by Monilia yunnanensis in China.
First Report of Brown Rot on Crataegus pinnatifida var. major Caused by Monilia yunnanensis in China.
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DOI：
10.1094/pdis-01-13-0085-pdn
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发表时间：
2013-08
期刊：
影响因子：
4.5
通讯作者：
Y. Zhao;D. Wang;Z. H. Liu
中科院分区：
文献类型：
--
作者：
Y. Zhao;D. Wang;Z. H. Liu
山楂；芒草是一种历史悠久的中草药，也是一种重要的经济水果，被加工成各种食品。耕地大多位于中国北方。2012年8月，中国辽宁省抚顺市发现一种成熟果树褐腐病。此病降低了果实的产量和品质；每棵树受影响的果实发生率在20%至35%之间。感染初期的特征是规则或不规则的浅棕色斑点变成深棕色，并逐渐形成许多灰色绒毛菌丝体。最后，病变扩大，导致果实腐烂或枯萎。采用组织分离法(1)从感染的果实中分离出病原菌，在25℃的马铃薯葡萄糖琼脂（PDA）上培养，光照12 h /黑暗12 h，培养7 d。7天后菌落直径达到60 ~ 75 mm，菌落呈淡绿色或淡黄色，边缘呈整齐的灰白色；气生菌丝有时形成环状。分生孢子为单、透明、柠檬形或椭圆形，直径为11.3±1.4 （8.0 ~ 16.5）× 6.4±0.8 (5.1 ~ 7.6)μm；孢子稀少，15天后形成的基质丰富，呈黑色，呈球形至椭圆形。分生孢子单生或分枝，在顶端有一个分生孢子。对引物ITS1和ITS4扩增的rDNA内部转录间隔区（ITS）进行双向直接测序。rDNA的ITS1-5.8S-ITS2序列与云南念珠菌（Monilinia yunnanensis）完全相同。HQ908788.1)，区别于近亲M. fructigena （AF150679.1）和M. polystroma （JX315717.1）。根据病原菌形态特征(2)和rDNA ITS序列（2,3）鉴定为云南支原体（M. yunnanensis）。在离体健康水果上进行致病性试验。用灭菌的钉子刺伤4个果实，在果实上表面放置菌丝PDA塞进行接种。另外4个果实用无菌PDA塞处理作为对照。果实在培养皿中培养，在25°C和90%的相对湿度下，光周期为12 h。接种果实5天后出现初步症状，对照组无症状。用上述方法从接种后的果实中重新分离出病原菌，鉴定为云南分枝杆菌。虽然有报道称云南分枝杆菌会引起桃上的褐腐病(2)，但据我们所知，这是云南分枝杆菌感染裙带菜（C. pinnatifida Bge）的首次报道。变体major N.在中国参考文献：(1)方正东。植物病害研究方法，1998。(2) M. J. Hu等。引起中国桃褐腐病的念珠菌属。PLoS ONE。在线出版。doi: 10.1371 / journal.pone。0024990, 2011。(3) g.c.m. van Leeuwen等。Mycol。Res. 106:444, 2002。
Crataegus pinnatifida Bge. var. major N. is a time-honored herbal medicine and an important economic fruit that is processed into various foods. Cultivated fields are mostly situated in northern China. In August 2012, a fruit brown rot disease on mature plants was found in Fushun, Liaoning Province, China. This disease reduced the yield and the quality of fruits; the incidence of fruits affected in each tree was between 20% and 35%. The initial stage of infection was marked by regular or irregular light brown spots turning dark brown and gradually supporting many grey fluffy tufts of mycelium. At last, the lesions expanded, causing the fruits to become rotted or withered. The pathogen was isolated from infected fruits by a tissue isolation method (1) and cultured on potato dextrose agar (PDA) at 25°C under 12 h light/12 h dark for 7 days. The colonies reached 60 to 75 mm in diameter after 7 days and were pale green or pale yellow with a neat greyish white margin; the aerial mycelium sometimes formed annulations. The conidia were single, hyaline, lemon-shaped or oval, and 11.3 ± 1.4 (8.0 to 16.5) × 6.4 ± 0.8 (5.1 to 7.6) μm; sporulation was sparse and stromata that formed after 15 days were abundant, black, and spherical to elliptical in shape. Conidiophores were simple or branched, bearing a single conidium on the tip. The internal transcribed spacer (ITS) region of rDNA amplified with primers ITS1 and ITS4 was directly sequenced in both directions. The ITS1-5.8S-ITS2 sequence of rDNA was 100% identical to Monilinia yunnanensis (GenBank Accession No. HQ908788.1), which is distinguished from the closely related M. fructigena (AF150679.1) and M. polystroma (JX315717.1). The pathogen was identified as M. yunnanensis on the basis of morphological characteristics (2) and the ITS sequence of rDNA (2,3). Pathogenicity tests were performed on detached healthy fruits. Four fruits were wounded with a sterilized nail and inoculated by placing a PDA plug of mycelia on upper surfaces of the fruits. Another four fruits treated with sterile PDA plugs served as a control. Fruits were cultured in petri dishes with a 12-h photoperiod at 25°C and 90% relative humidity. The initial symptoms on inoculated fruits were observed after 5 days, while no symptoms showed on the controls. The pathogen was reisolated from the inoculated fruit and identified as M. yunnanensis by the above methods. While M. yunnanensis has been reported to cause brown rot on peach (2), to our knowledge, this is the first report of M. yunnanensis infecting C. pinnatifida Bge. var. major N. in China. References: (1) Z. D. Fang. Research Methods of Plant Disease, 1998. (2) M. J. Hu et al. Monilinia species causing brown rot of peach in China. PLoS ONE. Online publication. doi:10.1371/journal.pone.0024990, 2011. (3) G. C. M. van Leeuwen et al. Mycol. Res. 106:444, 2002.