论文部分内容阅读
NPR1(non-expressor of pathogenesis-related gene 1)基因在拟南芥系统获得抗性中起着关键作用,可调控拟南芥植株广谱抗性的发生。本文报道了从心叶烟中克隆NPR1同源基因(NgNPR1)及其表达特性的研究结果。NgNPR1cDNA全长2 253 bp,编码588个氨基酸。将NgNPR1基因组全长与cDNA序列进行比对发现,NgNPR1基因组DNA含有4个外显子和3个内含子。Southern杂交分析表明,在心叶烟基因组中NgNPR1为单拷贝基因。采用绿色荧光蛋白在洋葱表皮瞬时表达的试验,证明了NgNPR1蛋白在水杨酸诱导时会从细胞质转运到细胞核中。Northern杂交分析发现,NgNPR1基因可以被与植物抗病相关的信号分子如水杨酸、茉莉酸甲酯、过氧化氢和乙烯所诱导。进一步研究发现,植物病原物如赤星病菌、青枯病菌和烟草花叶病毒对心叶烟植株的侵染也会使NgNPR1表达量增加。这些结果表明,NgNPR1基因在心叶烟植株抵御病原物侵染过程中可能起着重要作用。
NPR1 (non-expressor of pathogenesis-related gene 1) plays a key role in the resistance of Arabidopsis thaliana system and regulates the broad-spectrum resistance of Arabidopsis plants. This article reports the results of the cloning of the NPR1 homologue (NgNPR1) from the leaf of heart-leaf tobacco and its expression characteristics. The full length of NgNPR1 cDNA is 2 253 bp, encoding 588 amino acids. Comparing the full length of NgNPR1 with the cDNA sequence, NgNPR1 genomic DNA contained 4 exons and 3 introns. Southern hybridization analysis showed that NgNPR1 was a single copy gene in the leaf-leaf tobacco genome. Using transient expression of green fluorescent protein in onion epidermis, it was demonstrated that NgNPR1 protein is transported from the cytoplasm to the nucleus upon salicylic acid induction. Northern blot analysis showed that the NgNPR1 gene can be induced by signaling molecules associated with plant disease resistance, such as salicylic acid, methyl jasmonate, hydrogen peroxide and ethylene. Further study found that plant pathogens such as Alternaria alternata, bacterial wilt and tobacco mosaic virus infection of leaf tobacco plants will make NgNPR1 expression increased. These results indicate that the NgNPR1 gene may play an important role in the defense of leaf tobacco plants against pathogen infection.