【摘要】 2022-2023年在云南不同地区茶园发现茶褐斑病，通过分离纯化和柯赫氏证病试验获得4个形态特征和症状相近的真菌菌株（CYB01—CYB04）,在马铃薯葡萄糖琼脂（PDA）培养基平板上（25±1）℃下培养7 d后，菌落呈近圆形，直径53.1～76.8 mm;菌丝较发达，分隔，无色或浅灰色，分生孢子单细胞，无色或浅灰色，圆形或近圆形，2.6～6.8μm,据形态特征并参考有关文献初步鉴定其为一种附球孢菌（Epicoccum sp.）。通过PCR扩增获得内转录间区（ITS）序列均为539 bp, Blastn比对分析表明它们之间的相似率为100%,由此确认它们为同一种真菌。该菌（代表菌株CYB02）的ITS（NCBI登录号为OM100555）与高粱附球孢（E.sorghinum） EGJMP14菌株的ITS序列相似性为99.44%。其肌动蛋白（ACT）、翻译延伸因子（TEF1-α）和β-微管蛋白2（TUB2）基因序列分别为281 bp、 334 bp和388 bp;由MEGA 11软件构建基于蛋白基因拼接序列的系统发育树显示，CYB02与高粱附球孢E.sorghinum Guangxi-1处于同一末端分支上（自主支持率为98.0%）,因此将该病菌最终鉴定为高粱附球孢，并将该病害命名为茶附球孢褐斑病，其为云南茶树的一种新病害。病菌（CYB02）菌落生长的适宜温度为16～33℃,最适温度为25～27℃;在pH值为4～13的PDA培养基上均能生长，pH值为6～8时生长最快；黑暗和短时照（≤4 h/d）下适宜于病菌的生长，长光照下生长受到抑制；病菌培养的最佳碳源为葡萄糖或麦芽糖，最佳氮源为蛋白胨或酵母粉；PDA和马铃薯蔗糖琼脂（PSA）为该病菌的最适培养基。选择8种杀菌剂进行筛选试验，30%苯甲吡唑脂悬乳剂（SA）和40%苯醚甲环唑SA对病菌生长具有强抑菌和控病作用，抑菌率分别为91.80%和93.59%,室内盆栽控病率为89.17%和90.63%（p<0.01）;由这两种药剂原药毒力分析建立的回归模型计算得到有效抑制中浓度(EC₅₀)分别为1.510 7 mg/mL和1.283 7 mg/mL。更多还原

【Abstract】 During 2022-2023, brown spot disease was observed in tea gardens across various regions of Yunnan. Through isolation, purification, and Koch’s postulates testing, four fungal strains（CYB01—CYB04） with similar morphological and symptomatic characteristics were obtained. After 7 days of incubation on PDA medium at（25±1） ℃, the colonieswere subcircular with diametersranging from 53.1 to 76.8 mm. The hyphaewerewell-developed, septate, and colorless or light gray. The conidia were unicellular, colorless or light gray, circular or subcircular, measuring 2.6-6.8 μm in diameter. Based on morphological characteristics and relevant literature, the strain was primarily identified as Epicoccum sp. PCR amplification yielded ITS sequences of 539 bp each. Blast-n comparison revealed 100% similarity among the strains, confirming their identity as the same fungal species. The ITS sequence（NCBI accession number: OM100555） of a representative strain（CYB02） showed 99.44% similarity to that of Epicoccum sorghinum strain EGJMP14. The actin（ACT）, translation elongation factor 1-alpha（TEF1-α）, and beta-tubulin 2（TUB2） gene sequences measured 281 bp, 334 bp, and 388 bp, respectively. A phylogenetic tree constructed using concatenated protein-coding gene sequences via MEGA 11 software placed CYB02 in the same terminal clade as E. sorghinum Guangxi-1（bootstrap support value: 98.0%）. Consequently, the pathogen was conclusively identified as E. sorghinum, and the disease was designated as tea brown spot caused by Epicoccum sp. It represented a newly identified disease affecting tea plants in Yunnan. The preference temperature range for CYB02 growth was 16-33 ℃, with the optimum at 25-27 ℃. The pathogen grew on PDA medium across a pH range of 4-13, with the fastest growth observed at pH 6-8. The pathogen growthwasfavoredunderdark or short-daylight（≤4 h/d） conditions, while prolonged illumination inhibited growth. The most suitable carbon sources were glucose and maltose, and the optimal nitrogen sources were peptone and yeast powder. Potato dextrose agar（PDA） and potato sucrose agar（PSA）were the most suitable mediums for CYB02 growth. Screening tests involving eight fungicides demonstrated that Pyraclostrobin 30%SA and Difenoconazole 40%SA exhibited strong inhibitory and disease-control effects, with inhibition rates of 91.80% and 93.59%, respectively, and corresponding pot trial control efficacies of 89.17% and 90.63%（p<0.01）. Regression models based on virulence analysis of the active ingredients yielded EC₅₀ values of 1.510 7 mg/mL and 1.283 7 mg/mL for these two fungicides, respectively.更多还原