【目的】由稻曲病菌引起的稻曲病不仅造成水稻减产，而且还会产生对动物和植物有毒的真菌毒素。探明水稻幼穗对稻曲病菌毒素胁迫响应的分子机制，可为发掘水稻抗稻曲病基因以及抗病分子育种开辟新的思路。【方法】用稻曲病菌毒素处理水稻幼穗，采用转录组测序技术对水稻幼穗进行转录组测序，以水稻9311基因组作为参考基因组进行对比，利用TPM法计算基因表达量，设定参数（差异倍数的绝对值不小于2，且q值不大于0.05）筛选差异表达基因。结合基因差异表达分析、富集功能分析，鉴定水稻响应胁迫的关键基因，并利用实时荧光定量PCR技术对差异表达基因进行验证。【结果】在稻曲病菌毒素胁迫12 h后，水稻幼穗出现2526个差异表达基因（DEG）;通过GO富集、KEGG代谢途经和KOG功能分析，将差异基因划分为GO功能下的64个条目、32个代谢途径和KOG功能下23个类别，包括淀粉和蔗糖代谢、苯丙类生物合成、碳代谢、糖酵解/糖异生、氨基糖和核苷酸糖代谢等生物学过程。DEG中有66个植物转录因子，分属7种植物转录因子家族，包括WRKY和Myb两大转录因子。分析二萜类生物合成与淀粉和蔗糖代谢途径相关基因发现，OsCPS2、OsKSL4和细胞色素P450等基因表达量上调，而淀粉酶、β-呋喃果糖苷酶和UDP-焦磷酸化酶等基因表达量下调，推测这些基因在水稻响应稻曲病菌毒素胁迫时发挥重要的作用。【结论】稻曲病菌毒素作为非生物胁迫因素对水稻幼穗具有毒性;通过干扰淀粉和蔗糖代谢等途径而影响种子营养物质的合成，降低水稻抵抗病原菌侵染水稻的能力。

【Objective】 Rice false smut caused by Ustilaginoidea virens not only leads to rice yield loss, but also produces mycotoxins which is toxic to animals and plants. In order to elucidate the molecular mechanism behind the response to exposure to mycotoxin the young panicles of rice were mycotoxin-treated with U. virens mycotoxin, which may provide a new idea for exploring rice false smut resistance genes and molecular breeding for disease resistance. 【Method】Transcriptome sequencing was performed with mycotoxin-treated young panicles as materials. The genome of 9311 was used as the reference genome to align the sequences. The expression level of genes was calculated by the term of Transcripts Per Million (TPM). According to the database, the differentially expressed genes were screened by parameters (|LOG₂ fold change|≥1 and q-value≤0.05). Combined with differential expression analysis and function annotation, the key genes in response to mycotoxin were identified in rice panicles. The differentially expressed genes were verified by qRT-PCR. 【Result】2526 differentially expressed genes (DEG) were identified in young panicles of rice after 12 h treated with mycotoxin. Through GO enrichment, KEGG metabolic pathway and KOG function analysis, the DEGs were divided into 64 terms under GO function, 32 metabolic pathways and 23 categories under KOG function, including starch and sucrose metabolism, phenylpropyl biosynthesis, carbon metabolism, glycolysis/gluconeogenesis, amino sugar and nucleoside sugar metabolism and other biological processes. There were 66 plant transcription factors in DEGs, which belonged to 7 family of plant transcription factors, including WRKY and Myb. The expression levels of OsCPS2, OSKSL4 and cytochrome P450 were up-regulated, while the expression levels of amylase, beta-fructofuranosidase and UGPase were down-regulated when we analyzed genes involved in diterpenoid biosynthesis and starch and sucrose metabolism pathways. Therefore, it is speculated that these genes play an important role in rice response to mycotoxin of U. virens stress. 【Conclusion】As an abiotic stress factor, mycotoxin of U. virens had a toxic effect on young panicles of rice. It affects the synthesis of nutrients in seeds by interfering with metabolism of starch and sucrose, and thus reduces the resistance of rice to pathogen infection.