当归根腐病主要病原菌生物学特性及室内毒力测定

Biological Characteristics and Indoor Toxicity Test of Main Pathogens of Chinese Angelica(Angelica sinensis)Root Rot

为探究当归(Angelica sinensis)根腐病的病原菌种类、生物学特性并筛选其防治药剂。采用常规组织法分离培养病原菌,利用柯赫氏法则验证其致病性,通过形态学和分子生物学相结合的方法进行病原菌的鉴定、生物学特性分析;采用菌丝生长速率法对病原菌进行室内毒力测定。结果表明,当归根腐病菌菌落毛毡状,在三种培养基上大型分生孢子呈镰刀形,大小为(27.5~47.5)μm×(3.8~7.5)μm(n=50),隔膜数1~5;小型分生孢子在PDA和SNA培养基上呈椭圆形、肾型、纺锤形,在CLA培养基上肾型,(3.8~15.0)μm×(2.5~7.5)μm(n=50),隔膜数0~3;厚垣孢子在CLA培养基上呈串生,PDA培养基上呈不规则形,SNA培养基上厚垣孢子着生方式多样,串生、圆形、不规则形,大小为(2.5~3.8)μm×(2.5~5.0)μm(n=50)。EF-1α、RPB1和RPB2联合序列系统发育树表明,该菌为锐顶镰刀菌(Fusarium acuminatum),其最适生长温度为25℃,最适生长初始pH为9,光照对其生长无显著影响。室内毒力测定显示10%苯醚甲环唑(WG)对其抑制效果最好,EC50值为83.71 mg/L。本研究可为当归根腐病病原鉴定及田间药剂防治提供参考。

The aim of this study was to explore the taxonomic and biological characteristics of the pathogen inducing Chinese angelica(Angelica sinensis)root rot and screen its effective fungicides.Conventional tissue isolation method was used to isolate and culture the pathogen and its pathogenicity was tested according to Koch′s postulate.The identification and biological characteristics of the pathogen were detected by combination of morphology and molecular biology methods.The indoor toxicity of pathogens was determined according to the mycelial growth rate.The results showed that the colony of pathogen of A.sinensis root rot was felt-shaped.On three media,the macroconidia were falcate with the size of(27.5-47.5)μm×(3.8-7.5)μm(n=50)with 1-5 sepiments;the microconidia were elliptic,reniform,fusiform on PDA and on SNA media;it has diversified form of insertion style,concatenation,spherical,irregular,with the size of 2.5-3.8μm and reniform on CLA media,showing(3.8-15.0)μm×(2.5-7.5)μm(n=50)with 0 to 3 sepiments;the chlamydospores were formed in concatenation on CLA media;irregular on PDA media;spherical,irregular and formed on SNA media,showing(2.5-3.8)μm×(2.5-5.0)μm in size(n=50).The phylogenetic tree of the combined sequences was EF-1α,RPB1 and RPB2,demonstrated that the pathogen was Fusarium acuminatum.The optimum growth temperature of this pathogenic F.acuminatum was 25℃,the optimum initial pH was 9,and light has no significant effect on its growth.Indoor toxicity indicated that 10%difenoconazole WG achieved the greatest inhibitory effect on the F.acuminatum at a EC 50 value of 83.71 mg/L.This study provided a theoretical basis for pathogen identification and chemical control of A.sinensis root rot in field.