基于形态学和多基因位点鉴定甘肃秦艽斑枯病菌

Determin the Gansu Gentiana macrophylla Leaf Spot Pathogen by Morphology and Multi Locus Phylogeny

目的:旨在明确甘肃省栽培秦艽斑枯病病原菌分类地位及其生物学特性,为该病的防控提供一定的理论依据。方法:通过形态学和分子生物学方法相结合确定病原分类地位,利用常规植物病原学培养的方法测定病原菌生物学特性。结果:秦艽斑枯病菌分生孢子器近球形、扁球形、黑褐色,55.3~125.8μm×51.7~115.3μm(平均83.3μm×83.2μm);分生孢子细镰刀形、披针形,具1~5个隔膜,多为3个,大小18.8~30.6μm×2.4~3.5μm(平均23.5μm×3.2μm)。通过ITS、LSU、RBP2和β-tubline多基因位点构建系统发育树,将秦艽斑枯病病原菌鉴定为龙胆壳针孢Septoria gentianae Thüm.。该菌菌丝生长、分生孢子萌发和产孢的温度范围分别为0~35℃、5~30℃和15~25℃,最适温度分别为20~25、20和15℃;连续光照有利于菌丝生长,连续黑暗有利于孢子萌发和病菌产孢;此菌在相对湿度75%以上时均可萌发,以水中萌发最好;菌丝生长、分生孢子萌发和产孢的适宜p H范围分别为4.0~10.0、4.51~9.19和5.0~8.0,最适p H为6.0、6.49和6.5;土壤浸渍液以及秦艽叶或根浸渍液对孢子萌发有较强的促进作用。结论:秦艽斑枯病是秦艽生长中的主要病害,在栽培过程中应注意药剂防治。

Objective: To clarify the taxonomic status and biological characteristics of Gentiana macrophylla leaf spot pathogen inGansu Province,to supply scientific basis to the control of the disease. Methods: Morphology and molecular methods were combined to identifythe pathogen,biological characteristics were tested through regular cultural methods. Results: Gentiana macrophylla leaf spotpathogen was nearly spherical,oblate,black brown,(55.3~125.8)μm ×(51.7~115.3)μm(mean = 83. 3μm×83. 2μm)in diam; theconidium was sickle and lanceolate,with 1~5septum,almost three,(18.8~30.6)μm ×(2.4~3.5)μm(mean=23.5 μm × 3.2μm).The phylogenetic tree was constructed by four loci(ITS,LSU,RBP2 and β-tubline)dataset,which confirmed that the pathogen was Septoriagentianae Thüm. . The temperature range of the hypha growth,spore germination and production was 0~35℃,5~ 30℃ and 15~25℃, respectively. The optimum temperature was 20~25℃、20℃、15℃, correspondingly. Continuous illumination facilitated the hyphagrowth,and continuous darkness stimulated spore production and germination. The relative humidity for spore germination was above75%,spore germinates well in water. The pH range of the hypha growth,conidia germination and production was 4.0~10.0, 4.51~9.19 and 5.0~8.0,with the optimum was pH 6.0,6.49 and 6.5.Soil solution and Leaves or roots of Gentiana macrophylla impregnation solutionhad a strong role in promoting the germination of spores.Conclusion: Fungicide should be applied due to the Gentiana macrophyllaleaf-spot,which is the primary disease in Gentiana macrophylla cultivation.