金线兰茎腐病的病原菌鉴定与防治药剂的筛选

Pathogen identification of Anoectochium roxborghil stem rot and screening of fungicides

[目的]明确金线兰茎腐病病原菌ASP01菌株的种属分类,了解其对不同金线莲种质的致病力,并筛选有效的化学防治药剂。[方法]从福建省永安市金线莲种植基地分离纯化金线兰茎腐病的病原菌,通过形态学、ITS序列与EF-1α序列进化树分析鉴定其分类。通过接种不同兰科种质分析其致病力,用平板抑制法筛选有效的化学药剂。[结果]分离纯化获得了对金线兰具有致病力的菌株ASP01。经鉴定,该病原菌为尖孢镰刀菌。EF-1α序列进化树显示,ASP01与Fusarium oxysporum f.sp.opuntiarum最为接近。该菌可侵染福建的主要金线莲栽培种,其中滇南开唇兰、福建小圆叶、红霞病情指数较高,分别为10.00、9.95和4.69,而福建尖叶与台湾银线兰病情指数较低,分别为0.95和0.72。5 000倍液咪鲜胺水乳剂和2 500倍氟硅唑乳油对该病菌的抑菌率分别为93.83%和80.25%。[结论]从福建省永安市金线莲种植基地分离的金线兰茎腐病病原菌为尖孢镰刀菌,与F.oxysporum f.sp.opuntiarum最为接近。该菌在国内尚未见报道。ASP01菌株可侵染福建主要的金线莲栽培种,咪鲜胺和氟硅唑对该菌有较强抑制作用。

[Purpose]A strain causing Anoectochium roxborghil stem rot was isolated and classified in this study to analyze its pathogenicity to different Anoectochium germplasms.At the same time,effective chemical fungicides for the stain were screened.[Method]Strain ASP01 was isolated from a stem rot sample from A.roxborghil planting base in Yong′an City,Fujian Province,and then identified and classified based on morphology,ITS sequences and EF-1αsequences.Its pathogenicity was analyzed by inoculations to different germplasms of A.roxburghii and orchids.Meanwhile effective chemical fungicides for strain ASP01 were screened by plate inhibition method.[Result]The fungal strain ASP01,demonstrating pathogenicity to A.roxborghil,was identified as Fusarium oxysporum.It showed the closest relationship with F.oxysporum f.sp.opuntiarum according to phylogenetic trees based on EF-1αsequences.ASP01 was pathogenic to the majority cultivars of Anoectochium in Fujian,among which the disease indexes of A.burmannicus(10.00),Fujian xiaoyuanye(9.95)and Hongxia(4.69)were relatively higher,while those of Fujian jianye(0.95)and A.formosanus(0.72)were lower.The inhibition rates of liquid prochloraz aqueous emulsion(5000 times dilution)and flusilazole emulsifiable oil(2500 times dilution)to ASP01 were 93.83%and 80.25%,respectively.[Conclusion]The strain ASP01 causing stem rot in A.roxborghil was identified as F.oxysporum.It was closely related to F.oxysporum f.sp.opuntiarum,and wasn′t reported domestically.ASP01 was pathogenic to main cultivars of A.roxburghii in Fujian,and prochloraz and flusilazole exhibited strong inhibitory effects on it.