Abstract: NAC transcription factors constitute a plant-specific family that plays crucial roles in plant growth and development， hormone signal transduction， and responses to abiotic stresses. In this study， we systematically identified and bioinformatically characterized the NAC gene family in Carex siderosticta based on transcriptome data. By analyzing expression profiles， we screened out CsNAC16 as a key drought-responsive gene and subsequently performed its cloning and functional validation. The results revealed a total of 44 CsNAC gene members， which were classified into 13 subfamilies. These members differed in their physicochemical properties， and the majority were localized in the nucleus. Under drought stress， CsNAC16 exhibited the highest relative expression among all differentially expressed CsNAC family genes. The coding sequence （CDS） of CsNAC16 was cloned and found to be 510 bp in length， encoding 169 amino acids. The deduced protein is basic， stable， and hydrophilic， and shows the closest phylogenetic relationship with the NAC protein of C. rostrata. QRT-PCR analysis revealed that CsNAC16 expression was significantly induced by drought （mannitol）， salt （NaCl）， and abscisic acid （ABA） treatments. Heterologous overexpression of CsNAC16 in tobacco demonstrated that， under drought stress， the activities of superoxide dismutase （SOD）， peroxidase （POD）， and catalase （CAT） were significantly elevated in transgenic lines. Taken together， these findings suggest that CsNAC16 can function as a positive regulator that enhances drought tolerance by activating the antioxidant enzyme system. This study provides a theoretical foundation and candidate gene resources for drought-resistance molecular breeding in C. siderosticta.

Key words: Carex siderosticta, NAC gene family, Bioinformatics, CsNAC16, Drought stress

摘要： NAC转录因子是植物特有的转录因子，在植物生长发育、激素信号转导、响应非生物胁迫方面发挥重要作用。本研究基于转录组鉴定分析了宽叶薹草（Carex siderosticta）NAC基因家族，并筛选干旱响应关键基因CsNAC16，对其进行克隆与功能验证。结果表明，宽叶薹草中共鉴定出44个CsNACs成员，分属13个亚家族，其蛋白理化性质不同，大部分定位于细胞核。干旱胁迫下，在所有差异表达的CsNAC家族基因中，CsNAC16相对表达量最高。克隆获得CsNAC16基因编码区（CDS）长度为510 bp，编码169个氨基酸，属碱性稳定亲水蛋白，与灰株薹草（Carex rostrata）亲缘关系最近。qRT-PCR显示其对干旱、盐和ABA处理均有响应。在烟草中异源过表达CsNAC16发现，干旱胁迫下转基因株系的SOD、POD、CAT活性均显著提高。综上，CsNAC16可作为正向调控因子，通过激活抗氧化酶系统增强植物耐旱性。本研究为宽叶薹草抗旱分子育种提供了理论依据与基因资源。

关键词: 宽叶薹草, NAC基因家族, 生物信息学, CsNAC16, 干旱胁迫