Abstract: To identify the dominant pathogen causing Salvia miltiorrhiza root rot in Henan Province and clarify its infection process，diseased root samples were collected from three main producing areas（Yuzhou City，Mianchi County，and Fangcheng County）in Henan Province.The dominant pathogens were identified based on morphological characteristics and molecular biological analyses. Highly pathogenic isolates were screened through pathogenicity assays.The infection process of a selected isolate in S.miltiorrhiza roots was observed using green fluorescent protein（GFP）labeling and fluorescence microscopy.The results showed that Fusarium oxysporum exhibited the highest isolation frequencies（63.16%，48.28%，and 39.63%，respectively）among pathogens isolated from the three areas，indicating it as the dominant pathogen of S. miltiorrhiza root rot in Henan Province.Following inoculation of S.miltiorrhiza seedlings with F.oxysporum spore suspension：spores adhered to the root surface and began to germinate at 12 h post⁃inoculation（hpi）；germinated spores developed into hyphae，which spread along the intercellular spaces of epidermal cells between 24—48 hpi；hyphae expanded into the cortex and extended along parenchyma cells，eventually surrounding entire cells by 3—5 days post⁃inoculation（dpi）；extensive hyphal networks formed randomly within cortical cells by 7—9 dpi；hyphae surrounded the entire root cortex and extended to the root tip by 11 dpi；all root cells were infected by 14 dpi.At this stage（14 dpi），the stem base turned brown，fibrous roots became brittle and easily broken，and root tips of some plants turned yellow.In conclusion，F.oxysporum is the dominant pathogen causing S.miltiorrhiza root rot in Henan Province.This study elucidated the infection process of GFP⁃labeled F.oxysporum in S.miltiorrhiza roots from a histopathological perspective，providing a basis for targeted control strategies against this disease.

Key words: Salvia miltiorrhiza, Root rot, Fusarium oxysporum, Infection process, Fluorescence microscopy observation

摘要： 为明确河南省丹参根腐病的优势病原菌及其侵染过程，采集了河南省禹州市、渑池县、方城县3个丹参主产区丹参根腐病样品，结合形态学和分子生物学方法鉴定了优势病原种类，并通过致病力分析筛选出强致病力菌株，进而利用绿色荧光蛋白（GFP）标记和荧光显微观察技术开展了病原菌侵染丹参根部的过程观察。结果表明，尖孢镰孢菌（Fusarium oxysporum）在河南省3个丹参主产区丹参根腐病病原中的分离频率均最高，分别为63.16%、48.28%和39.63%，是引起河南省丹参根腐病的优势病原菌；利用尖孢镰孢菌孢子悬浮液对丹参幼苗灌根接种，接种后12 h孢子吸附在根表面并开始萌发，24~48 h孢子萌发成菌丝并沿表皮细胞间隙蔓延，3~5 d菌丝扩展到皮层并沿薄壁细胞蔓延直至包围整个细胞，7~9 d大量菌丝在根皮层细胞随机扩展并逐渐形成网状结构，11 d时菌丝包围整个根皮层细胞并扩展到根尖，14 d后整个根部细胞均被侵染，此时植株茎基部发褐，须根易断，少许植株根尖发黄。综上，尖孢镰孢菌为河南省丹参根腐病的优势病原，从组织病理学角度明确了GFP标记的尖孢镰孢菌侵染丹参根部的过程，为丹参根腐病的精准防控提供了参考。

关键词: 丹参, 根腐病, 尖孢镰孢菌, 侵染过程, 荧光显微观察