Department of Ornamental Horticulture, Sichuan Agricultural University, 555 Northeast Road, Wenjiang District, Chengdu, Sichuan 611130, People's Republic of China.
Biotechnol Lett. 2011 Oct;33(10):2073-82. doi: 10.1007/s10529-011-0659-8. Epub 2011 Jun 10.
The plant-specific NAC (for NAM, ATAF1, 2 and CUC2) transcription factors (TFs) have been implicated in different cellular processes involved in stress responses such as cold, high salinity or drought as well as abscisic acid (ABA) signalling. However, the roles of the chrysanthemum NAC TF genes in plant stress responses are still unclear. A full-length cDNA designated DgNAC1, containing a highly conserved N-terminal DNA-binding NAC domain, has been isolated from chrysanthemum by RACE (rapid amplification of cDNA ends). It encodes a protein of 284 amino acids residues (=~32.9 kDa) and theoretical pI of 7.13. The transcript of DgNAC1 was enriched in roots and flowers than in stems and leaves of the adult chrysanthemum plants. The gene expression was strongly induced by ABA, NaCl, drought and cold treatment in the seedlings. Subcellular localization revealed that DgNAC1:GFP fusion protein was preferentially distributed to nucleus. To assess whether DgNAC1 is a practically useful target gene for improving the stress tolerance of chrysanthemum, we ectopically over-expressed the full-length DgNAC1 cDNA in tobacco and found that the 35S:DgNAC1 transgenic tobacco exhibited a markedly increased tolerance to salt. Despite this increased salt stress tolerance, the transgenic tobacco showed no detectable phenotype defects under normal growth conditions. These results proposed that DgNAC1 is appropriate for application in genetic engineering strategies aimed at improving salt stress tolerance in chrysanthemum.
植物特异性 NAC（NAM、ATAF1、2 和 CUC2）转录因子（TFs）已被涉及到不同的细胞过程，如冷、高盐或干旱以及脱落酸（ABA）信号转导的应激反应。然而，菊花 NAC TF 基因在植物应激反应中的作用仍不清楚。通过 RACE（快速扩增 cDNA 末端）从菊花中分离出全长 cDNA，命名为 DgNAC1，它包含一个高度保守的 N 端 DNA 结合 NAC 结构域。它编码一个由 284 个氨基酸残基组成的蛋白质（~32.9 kDa）和理论 pI 为 7.13。DgNAC1 的转录本在成年菊花植物的根和花中比茎和叶中富集。在幼苗中，基因表达强烈被 ABA、NaCl、干旱和低温诱导。亚细胞定位表明，DgNAC1:GFP 融合蛋白优先分布到细胞核。为了评估 DgNAC1 是否是一种实用的目标基因，用于提高菊花的应激耐受性，我们在烟草中异位过表达全长 DgNAC1 cDNA，并发现 35S:DgNAC1 转基因烟草对盐表现出明显的耐受性增加。尽管这种耐盐性增加，但转基因烟草在正常生长条件下没有表现出可检测的表型缺陷。这些结果表明，DgNAC1 适合应用于遗传工程策略，旨在提高菊花的耐盐性。
