北苍术枝枯病病原菌（Fusarium equiseti）的鉴定及其生物学特性研究

近年来，随着北苍术栽培面积的扩大，病害发生日趋严重。为了明确引起北苍术枝枯病病原菌及其生物学特性，利用柯赫氏法则、形态学特征及分子生物学技术对菌株进行了鉴定，并测定了菌丝生长最佳条件。结果表明，气生菌丝初期呈绒毛状至棉絮状、白色至粉红色、后期发展成驼色，分生孢子镰刀型、弯曲、中部细胞显著膨大、顶孢延长呈锥形、多数为3~7个分隔，厚垣孢子呈球形、成链状或单生于菌丝或孢子中。该致病菌的ITS序列与GenBank中木贼镰刀菌Fusarium equiseti（MK621018）的相似性为 100%，结合形态特征与分子鉴定最终将其确定为木贼镰刀菌,GenBank登录号(MH290363)。该菌菌丝生长最适温度范围为25~30 ℃；菌丝在pH 4~11时均能正常生长，pH 8~11时生长最快；燕麦及玉米面培养基最适合该病原菌生长；光照对菌丝生长有很大影响，全光照条件菌丝生长最快；对碳源淀粉、葡萄糖及氮源酵母浸出粉利用率最高，培养7 d时菌落直径在7 cm左右。

Identification and Biological Characteristics of the Pathogen (Fusarium equiseti) Causing Shoot Blight of Atractylodes chinensis

In recent years, with the expansion of the cultivation area of Atractylodes chinensis, the disease damage caused by pathogen has become more and more severe. To investigate the pathogen causing shoot blight of Atractylodes chinensis and its biological characteristics, the pathogen was identified based on the Koch’s postulates, morphological characteristics, molecular biological technology, and the optimum growth rate of mycelium were determined. The results showed that the aerial hyphae was villous to cotton-like, white to pink initially and turned camel color later, with sickle and curved conidia, significantly enlarged central cells, tapered apical spores, mostly had 3~7 compartmentals, spherical chlamydospores, chainlike or monogenic hyphae or spore. The pathogen ITS sequence shared 100% identity with that of Fusarium equiseti in GenBank (MK621018), and the pathogen was confirmed as Fusarium equiseti (GenBank accession No. MH290363). The optimum temperature for mycelial growth was 25~30 ℃, the mycelial grew at pH 4~11, and the optimum pH was 8~11. Oat and corn flour culture medium were the most suitable for mycelial growth; light conditions had great influence on the mycelium growth, and full light accelerated mycelial growth. The highest utilization rate of carbon-source starch, glucose and nitrogen-sourced yeast leaching powder was highest, and the diameter of the colony was about 7 cm when cultured for 7 d. The utilization rate of starch, glucose and yeast extract powder was the highest, and the diameter of the colony was about 7 cm when cultured 7 d.