Climate change has caused serious problems related to the productivity of agricultural crops directly affecting human well-being. Plants have evolved to produce molecular mechanisms in response to environmental stresses, such as transcription factors (TFs), to cope with abiotic stress. The NAC proteins constitute a plant-specific family of TFs involved in plant development processes and tolerance to biotic and abiotic stress. Sugarcane is a perennial grass that accumulates a large amount of sucrose and is a crucial agro-industry crop in tropical regions. Our previous transcriptome analyses on sugarcane that were exposed to drought conditions revealed significant increases in the expression of several NAC TFs through all of the time-point stress conditions. In this work, we characterize all previously detected sugarcane NAC genes, utilizing phylogenetics and expression analyses. Furthermore, we characterized a sugarcane NAC gene orthologous to the senescence-associated genes AtNAP and OsNAP via transient expression in tobacco calluses, from Arabidopsis and rice respectively, thus we named it the SoNAP gene. Transient localization assays on onion epidermal cells confirmed the nuclear localization of the SoNAP. Expression analysis showed that the SoNAP gene was induced by high salinity, drought, and abscisic acid treatments. The overexpression of the SoNAP gene in tobacco calluses caused a senescence associated phenotype. Overall, our results indicated that the SoNAP gene from sugarcane is transcriptionally induced under abiotic stress conditions and conserved the predicted senescence-associated functions when it was overexpressed in a heterologous plant model. This work provides key insights about the senescence mechanisms related to abiotic stress and it provides a benchmark for future work on the improvement of this economically important crop.

气候变化已引起与农作物生产力相关的严重问题，直接影响人类的福祉。植物已经进化出能够响应环境胁迫（例如转录因子（TFs））的分子机制，以应对非生物胁迫。NAC蛋白构成植物特有的TF家族，参与植物发育过程以及对生物和非生物胁迫的耐受性。甘蔗是多年生的草，积累了大量的蔗糖，是热带地区的重要农作物。我们之前在甘蔗上进行的转录组分析表明，在所有时间点胁迫条件下，这些甘蔗都暴露于干旱条件下，NAC TFs的表达显着增加。在这项工作中，我们表征了所有先前检测到的甘蔗NAC基因，利用系统发育和表达分析。此外，我们通过瞬时表达分别在拟南芥和水稻中的烟草愈伤组织中表征了与衰老相关基因AtNAP和OsNAP直系的甘蔗NAC基因，因此我们将其命名为SoNAP基因。洋葱表皮细胞的瞬时定位分析证实了SoNAP的核定位。表达分析表明，SoNAP基因是由高盐度，干旱和脱落酸处理诱导的。SoNAP基因在烟草老茧中的过表达引起衰老相关的表型。总体而言，我们的结果表明，在非生物胁迫条件下，甘蔗中的SoNAP基因被转录诱导，并且在异源植物模型中过表达时，它保留了预期的衰老相关功能。