内蒙古自治区紫花苜蓿根腐病病原菌鉴定

Identification of Pathogen of Alfalfa Root Rot in Inner Mongolia

为明确内蒙古自治区紫花苜蓿根腐病的主要病原菌种类,从内蒙古自治区5市12个样点采集紫花苜蓿根腐病病样,采用常规组织分离法对病原菌进行分离与纯化,利用形态学结合ITS和EF-1α基因序列鉴定分离物种类,按照柯赫氏法则测定其致病性。结果显示,5市12个样点共分离出425株真菌,按照菌株的菌落和分生孢子形态,结合基因序列鉴定为5属17种,分别为锐顶镰刀菌(Fusarium acuminatum)、茄病镰刀菌(F. solani)、木贼镰刀菌(F.equiseti)、变红镰刀菌(F. incarnatum)、尖孢镰刀菌(F. oxysporum)、燕麦镰刀菌(F. avenaceum)、轮枝镰刀菌(F.verticillioides)、层出镰刀菌(F. proliferatum)、F. falciforme、F. neocosmosporiellum、三线镰刀菌(F. tricinctum)、F.virguliforme、芬芳镰刀菌(F.redolens)、立枯丝核菌(Rhizoctoniasolani)、织球壳枯萎菌(Plectosphaerella cucumerina)、茎点霉(Phoma medicaginis)和根异茎点霉(Paraphoma radicina),其中轮枝镰刀菌、F. falciforme、F.neocosmosporiellum和F. virguliforme引发苜蓿根腐病在世界范围内首次报道。致病性测定表明,17种真菌均能够引起紫花苜蓿根腐病。紫花苜蓿根腐病可由单一病原菌或2~4种病原菌复合侵染引起,且不同地区的致病种群结构不同,但优势致病种均为锐顶镰刀菌。

In order to clarify the main pathogens of alfalfa root rot disease in Inner Mongolia,samples of alfalfa root rot disease were collected from 12 sites in 5 cities of Inner Mongolia.The pathogens were isolated and purified using conventional tissue separation methods.The isolates were identified by morphology combined with ITS and EF-1αgene sequence,and the pathogenicity was determined according to Koch′s rule.The results showed that 425 fungi of 17 species of 5 genera were isolated from 12 samples in 5 cities.They were Fusarium acuminatum,F.solani,F.equiseti,F.incarnatum,F.oxysporum,F.avenaceum,F.verticillioides,F.proliferatum,F.falciforme,F.neocosmosporiellum,F.tricinctum,F.virguliforme,F.redolens,Rhizoctonia solani,Plectosphaerella cucumerina,Phoma medicaginis and Paraphoma radicina,in which alfalfa root rot caused by F.verticilliforme,F.falciforme,F.neocosmosporiellum and F.virguliforme was first reported worldwide.The pathogenicity test showed that 17 kinds of fungi could cause alfalfa root rot.Alfalfa root rot disease could be caused by a single pathogen or a combination of 2-4 pathogens,and the pathogenic population structure was different in different regions,but the dominant pathogenic species was F.acuminatum.