目的 比较尾叶桉Eucalyptus urophylla 对水肥单、双因素胁迫的分子响应机制，为桉树抗逆育种提供思路和分子基础。方法 以无性系ZQUA44为试验材料，设3个水肥胁迫处理和1个对照（CK）。水肥双因素胁迫：20%~40%田间持水量，基肥[钙镁磷肥(CMPF) 250 g]；水分单因素胁迫：20%~40%田间持水量，基肥(CMPF 250 g+复合肥150 g)；养分单因素胁迫：60%~80%田间持水量，基肥(CMPF 250 g)；CK：60%~80%田间持水量，基肥(CMPF 250 g+复合肥150 g)。水分单因素胁迫和对照在种植2个月后施尿素100 g，8月份施复合肥150 g，第2年春天施复合肥100 g。对受胁迫处理的尾叶桉进行生长指标测定，并取叶片进行转录组测序，对测序结果进行拼接，利用生物信息学手段获得差异表达基因，对差异基因进行GO功能注释和KEGG通路分析。最后随机选择4个具有不同表达模式的差异表达基因进行qRT-PCR，验证转录组测序数据的可信度。结果 3种胁迫处理均在一定程度上抑制尾叶桉的生长发育，胁迫处理下尾叶桉各项生长指标多显著低于对照。水肥双因素胁迫、水分单因素胁迫和养分单因素胁迫处理共得到5 547个差异表达基因，分别有2 585、1 472和1 490个差异表达基因，各有1 195、222和665个基因表达上调和1 390、1 250和825个基因表达下调；3种胁迫处理分别获得155、75和108个基因编码转录因子。水肥单、双因素处理的差异表达基因均显著富集在苯丙烷的生物合成路径中。qRT-PCR结果与转录组测序结果基本一致，说明测序结果可信。结论 尾叶桉在3种胁迫处理下的转录变化具有明显的普遍性和特异性，综合胁迫对植物生长的影响比单独胁迫的影响更大，不同胁迫条件下植物可能具有不同的响应方式。
Objective To compare the molecular response mechanisms of Eucalyptus urophylla under single and dual factor stresses of water and nutrient, and provide insight and molecular basis for resistance breeding of Eucalyptus.Method The experiment selected E. urophylla clone ZQUA44 as matetial, and set three stress treatments and one control (CK). Water and nutrient deficiency stress: 20%-40% field moisture capacity, applying 250 g calcium magnesium phosphate fertilizer (CMPF) as base fertilizer; Water deficiency stress: 20%-40% field moisture capacity, applying 250 g CMPF and 150 g compound fertilizer as base fertilizer; Nutrient deficiency stress: 60%-80% field moisture capacity, applying 250 g CMPF as base fertilizer; CK: 60%-80% field moisture capacity, applying 250 g CMPF and 150 g compound fertilizer as base fertilizer. The urea of 100 g was applied at two months after planting, 150 g compound fertilizer in August, and 100 g compound fertilizer in the next spring in water deficiency stress and control treatments. High-throughput transcriptome sequencing was performed to E. urophylla leaves in different stress treatments, and the growth indexes of plant were determined. After assembling, differentially expressed genes were obtained using bioinformatics methods, and GO functional annotations and KEGG pathway analyses were performed. Finally, four differentially expressed genes with different expression patterns were randomly selected for qRT-PCR to validate the reliability of transcripcome sequencing data.Result All three stress treatments partly suppressed the growth and development of E. urophylla. Most of the growth indexes of E. urophylla in three stress treatments were significantly lower than those in control. A total of 5 547 differentially expressed genes were obtained in water and nutrient deficiency treatment, water deficiency treatment and nutrient deficiency treatment. The 2 585, 1 472 and 1 490 differentially expressed genes were obtained, including 1 195, 222 and 665 up-regulated genes and 1 390, 1 250 and 825 down-regulated genes, respectively. The 155, 75, 108 gene encoding transcription factors were respectively obtained in three stress treatments. The differentially expressed genes in three stress treatments were all significantly enriched in phenylpropane biosynthetic pathway. The qRT-PCR results were basically consistent with transcriptome sequencing results, indicating that the sequencing results were credible.Conclusion The transcriptional changes of E. urophylla in three stress treatments have obvious universality and specificity, and the effects of dual factor stress on plant growth are more than that of single factor stress. Plant may have different responce modes in different stress conditions.