中高型有髯鸢尾根腐病病原分离与鉴定

Isolation and Identification of Pathogens from the Root Rot of Bearded Iris of Middle-tall Type

中高型有髯鸢尾易发生根腐病,在全国各地均有发生,为害严重。为对中高型有髯鸢尾根腐病精准防治提供科学依据,开展了中高型有髯鸢尾根腐病病原鉴定研究。以郑州绿城广场采集的Iris germanica ‘Edward of Windsor’、Iris germanica ‘Ola Kala’和Iris germanica ‘Alcazar’鸢尾根腐病标本为试验材料,采取植物组织分离和根际土壤提取的方法对病原菌进行培养、分离、纯化,依据柯赫氏法则进行鸢尾根际接种确定鸢尾根腐病主要致病病原菌的基本类型;通过形态学对比和分子生物学鉴定确定致病病原的种类。结果表明:从鸢尾病株和根际土壤中共获得6种形态特征不同的真菌,利用柯赫氏法则鉴定出了YW-1、YW-2两种鸢尾根腐病的致病病原真菌;通过对两种病原真菌的菌丝形态、颜色、孢子与孢子梗形态、发育规律进行形态学鉴定,以及对两种病原真菌的DNA提取、电泳、基因测序、ITS基因位点对比、NJ法构建生长发育树等进行分子生物学鉴定,检测出与两种病原真菌相对应的rDNA-ITS基因序列的同源性均在99%以上,确定此两种致病病原真菌分别为YW-1:腐皮镰刀菌(Fusarium solani),YW-2:葡萄座球腔菌(Boryosphaeria dothidea)。综上,本研究认为鸢尾根腐病是由腐皮镰刀菌(Fusarium solani)和葡萄座球腔菌(Boryosphaeria dothidea)两种病原的复合侵染所致。本研究为中高型有髯鸢尾根腐病的综合防治提供了科学依据。

Bearded irises of middle-tall type are prone to root rot,which occurs all over the country,causing serious damage.In order to provide scientific basis for accurate prevention and control of bearded iris root rot of middle-tall type,the pathogen identification of bearded iris root rot of middle-tall type was carried out.Iris germanica'Edward of Windsor',Iris germanica'Ola Kala'and Iris germanica'Alcazar'root rot specimens collected from Lv Cheng Square in Zhengzhou were used as experimental materials.The pathogen was cultured,isolated and purified by plant tissue separation and rhizosphere soil extraction.According to Koch's postulates,the rhizosphere inoculation ofiris was carried out to determine the basic types ofthe main pathogenic bacteria ofiris root rot.The pathogenic pathogens were identified by morphological comparison and molecular biological identification.The results showed that a total of six fungi with different morphological characteristics were obtained from diseased iris plants and rhizosphere soil.Two pathogenic fungi of iris root rot,YW-1 and YW-2,were identified by Koch's postulates.By morphological identification of mycelium morphology,color,spore and spore pedol morphology and development rules of the two pathogenic fungi,as well as molecular biological identification of DNA extraction,electrophoresis,gene sequencing,ITS gene locus comparison,and growth and development tree construction by NJ method,the homology of rDNA-ITS gene sequences corresponding to the two pathogenic fungi was more than 99%.The two pathogenic fungi were identified as YW-1:Fusarium solani,and YW-2:Boryosphaeria dothidea.In summary,this study concluded that the root rot of iris was caused by the combined infection of Fusarium solani and Boryosphaeria dothidea.The results provides a scientific basis for the comprehensive control of the root rot of bearded iris.