摘要
为明确广东香葱炭疽病的病原菌种类,在广东省香葱主要产区惠州市和韶关市采集香葱炭疽病疑似病株,分离、纯化病原菌;通过病原菌分生孢子悬液接种活体香葱植株和离体植株叶片,柯赫氏法则验证,明确病原菌的致病性;通过观察病原菌的形态特征,结合其核糖体内转录间隔区(ITS)、肌动蛋白(ACT)、几丁质合成酶1 (CHS1)、甘油醛-3-磷酸脱氢酶(GAPDH)和β微管蛋白(TUB2)基因部分序列的多基因分子系统学分析等方法,确定病原菌的分类地位。从病样中分离获得23个形态特征相似的单分生孢子分离物。致病性人工接种结果表明,供试菌株分生孢子在20和25℃下均可侵染香葱产生与田间相似的炭疽病症状,老叶较嫩叶更易感病。20℃在PDA培养基上,供试菌株菌落呈灰色,菌丝生长速度较快;25和28℃菌丝生长较慢,菌落呈花瓣状;后期在菌落表面形成橘红色分生孢子堆。分生孢子梗透明,顶端簇生分生孢子;分生孢子透明,单细胞,微弯,大小13.1~19.6μm×3.2~3.9μm。附着胞深棕色,形状不规则,大小11.7~25.5μm×5.0~14.3μm;刚毛深棕色至浅棕色,基部膨大,顶端尖或圆滑,长为44.5μm×106.4μm。这些形态特征与白蜡树刺盘孢(Colletotrichum spaethianum)基本一致。供试菌株的ITS、ACT、CHS1、GAPDH和TUB2基因序列与白蜡树刺盘孢模式菌株CBS167.49对应基因序列的一致性为99.46%~100%。系统发育树显示,该菌株与白蜡树刺盘孢的3个菌株单独聚成一支。明确了广东香葱炭疽病的病原菌为白蜡树刺盘孢,这是白蜡树刺盘孢侵染香葱引起香葱炭疽病的首次报道。
To clarify the taxonomy of the pathogen causing Allium ascalonicum anthracnose in Guangdong, diseased plant samples of A. ascalonicum showing anthracnose symptoms from Huizhou and Shaoguan in Guangdong were collected as test materials. Strains were isolated and purified by conidial suspension dilution method. The pathogenicity of these strains was determined by the Koch’s postulates with in vivo or in vitro inoculation of conidial suspension on plants of A. ascalonicum. The pathogen was identified based on morphological characteristics, combined with polygene sequence analysis and phylogenetic analysis method using partial sequences of internal ribosome transcribed spacer(ITS),actin(ACT),chitin synthase 1(CHS1),glyceraldehyde-3-phosphate dehydrogenase(GAPDH)and β-tublin(TUB2). Results showed that 23 single-conidium-isolates with similar morphological characteristics were obtained from diseased plant samples of A. ascalonicum showing anthracnose symptoms. Artificial in vivo and in vitro inoculation results showed that the tested isolate could infect A. ascalonicum and cause typical anthracnose symptoms both at 20 ℃ and 25 ℃. Old leaves were more susceptible than young leaves. On PDA medium,the colony was gray,and mycelia of the tested isolate grew evenly and fast at 20 ℃. But it grew abnormally and slowly,the colony showing petal-like shape at 25 ℃ and 28 ℃. Conidiomata in orange color were formed on the surface of the colony. Conidiophores were hyaline with conidia on the top. Conidia were hyaline,single-spore,slightly curved,13.1–19.6 μm × 3.2–3.9 μm. Appressoria were dark brown,irregular shapes,11.7–25.5 μm × 5.0–14.3 μm. Setae were light brown to dark brown,with enlarged base and pointy or rounded tip,44.5 to 106.4 μm in length. These morphological characteristics were similar with Colletotrichum spaethianum. Sequence identities of partial sequences of ITS,ACT,CHS1,GAPDH and TUB2 genes of representative isolates were 99.46% to 100% identical to the ex-holotype strain CBS 167.49. The phylogenetic tree showed that two representative isolates were grouped together with three C. spaethianum strains to form a single clade. This study clarified that the pathogen causing A. ascalonicum anthracnose in Guangdong was determined as C. spaethianum and reported for the first time that C. spaethianum could cause A. ascalonicum anthracnose.
作者
于琳
佘小漫
汤亚飞
蓝国兵
李正刚
何自福
YU Lin;SHE Xiaoman;TANG Yafei;LAN Guobing;LI Zhenggang;HE Zifu(Plant Protection Research Institute,Guangdong Academy of Agricultural Sciences,Guangzhou 510640,China;Guangdong Provincial Key Laboratory of High Technology for Plant Protection,Guangzhou 510640,China)
出处
《园艺学报》
CAS
CSCD
北大核心
2022年第1期129-140,共12页
Acta Horticulturae Sinica
基金
国家自然科学基金项目(31901841)
广东省重点领域研发计划项目(2018B020205003,2019B020217003-05)
广东省科技创新战略专项(高水平农科院建设)(R2018QD-057)
广东省农业科学院“十四五”学科团队建设项目(202105TD)。
关键词
香葱
炭疽病
白蜡树刺盘孢
病原鉴定
Allium ascalonicum
anthracnose
Colletotrichum spaethianum
pathogen identification
