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核转录因子Y(nuclear transcription factor Y,NF-Y)类转录因子在植物生长发育和非生物胁迫响应基因表达调控中发挥重要的作用,NF-Y由3种亚基(NF-YA、NF-YB、NF-YC)组成。本研究从抗逆性强的谷子品种龙谷25中克隆1个新的NF-Y类转录因子基因Si NF-YA5。该基因序列为924 bp,编码307个氨基酸,分子量为33.76 k D,等电点为9.19。Si NF-YA5在149~210位氨基酸之间含有CBF保守结构域。亚细胞定位分析表明,Si NF-YA5定位于细胞膜和细胞核。基因功能分析显示,在不同浓度高盐处理下,和野生型拟南芥(WT)相比Si NF-YA5转基因拟南芥种子萌发率更高;苗期Si NF-YA5转基因拟南芥根表面积和植株鲜重显著高于WT,证明过表达Si NF-YA5基因可以显著提高植物耐盐性。基因表达分析结果显示,在Si NF-YA5转基因拟南芥中参与盐胁迫响应的基因NHX1和LEA7的表达量明显高于WT。另一方面,Si NF-YA5转基因拟南芥与WT相比对于ABA的敏感性差异不显著,以上结果证明Si NF-YA5主要通过ABA非依赖途径提高转基因植物对高盐胁迫的耐性。
The nuclear transcription factor Y (NF-Y) transcription factor plays an important role in the regulation of plant growth and abiotic stress response gene expression. NF-Y is composed of three subunits (NF-YA, NF- YB, NF-YC). In this study, a new NF-Y transcription factor gene Si NF-YA5 was cloned from a highly resistant millet variety, Longgu 25. The gene sequence was 924 bp, encoding 307 amino acids with a molecular weight of 33.76 kD and an isoelectric point of 9.19. Si NF-YA5 contains a CBF conserved domain between amino acids 149-210. Subcellular localization analysis showed that Si NF-YA5 localized in the cell membrane and nucleus. The analysis of gene function showed that the seed germination rate of Si NF-YA5 transgenic Arabidopsis thaliana seedlings was higher than wild-type Arabidopsis thaliana (WT) seedlings under high salt stress; the root surface area of Si NF-YA5 transgenic Arabidopsis thaliana And plant fresh weight were significantly higher than WT, indicating that overexpression of Si NF-YA5 gene can significantly improve plant salt tolerance. Gene expression analysis showed that the expression of genes NHX1 and LEA7 involved in salt stress response in Si NF-YA5 transgenic Arabidopsis thaliana was significantly higher than WT. On the other hand, Si NF-YA5 transgenic Arabidopsis showed no significant difference in its sensitivity to ABA compared to WT. These results demonstrate that Si NF-YA5 enhances tolerance of transgenic plants to high salt stress mainly through an ABA-independent pathway.