烟草是一种重要的经济作物，尼古丁是烟草中重要的次生代谢物，其含量是衡量烟草制品的重要指标。尼古丁的合成受到茉莉素信号途径的调控，尼古丁合成代谢途径中的关键酶基因，如PMT、QPT、ODC与A622等均受茉莉素诱导而表达。茉莉素介导的尼古丁合成的分子机制大致概括如下；当体内含有生物活性的茉莉素（JA-Ile）时COI1会与JAZ蛋白结合，使JAZ泛素化从而被26S蛋白酶体降解；JAZ蛋白的降解会释放MYC2/bHLH2类转录因子激活PMT和QPT等基因的表达。前人研究发现茉莉素信号通路中的关键成分COI1、NtJAZ和MYC2都是尼古丁合成中的重要调控子，故解析新的茉莉素信号通路成分可以为进一步阐明尼古丁合成的分子机制提供重要线索。 本研究基于实验室前期利用酵母双杂文库筛选到的与NtJAZ1互作的蛋白AIDP，研究AIDP在尼古丁合成中的作用。首先利用荧光素酶互补技术对AIDP与NtJAZ1等蛋白的互作情况进行了进一步验证。结果显示，在烟草叶片瞬时表达体系中AIDP与NtJAZ1存在互作，而AIDP与MYC2a不存在互作，这暗示AIDP可能是一个潜在的参与茉莉素信号通路的新因子。对AIDP的表达模式研究表明，AIDP在烟草的根、茎、叶和花中广泛表达，并无器官特异性，在根和茎中表达量相对较高，而在叶和花中表达量相对较低。用茉莉素处理烟草BY-2细胞发现AIDP的表达不受茉莉素的诱导。 本研究构建了AIDP过表达的转基因烟草，通过对尼古丁合成关键基因的检测发现：与野生型相比，AIDP的过表达会明显上调茉莉素诱导的尼古丁合成关键基因PMT、QPT、ODC及A622的表达，而未经茉莉素处理的转基因植株中这些基因的表达与野生型没有区别。利用PMT基因启动子GAG片段激活实验表明，AIDP可以激活GAG片段的转录活性，这暗示AIDP可能通过结合GAG片段激活PMT的表达从而调控尼古丁的合成。除此之外，我们还对茉莉素信号通路的其他关键基因进行了检测。结果表明，过表达AIDP不管在有无茉莉素处理的情况下都能上调NtJAZ1的表达，而对bHLH2基因没有影响。 综上所述，NtJAZ1互作蛋白AIDP可能是茉莉素信号通路的一个新成分，通过激活尼古丁合成基因的表达从而调控尼古丁的合成。上述结果为进一步阐明尼古丁合成的转录调控机制奠定了基础。

Nicotine is the main alkaloid in tobacco, its biosynthesis is up-regulated by Jasmonates (JA). JA can induce the transcription of nicotine biosynthetic genes, such as PMT, QPT, MPO and A622. The signal pathway of JA regulating nicotine biosynthesis is as following: In the absence of JA, JAZs interact with MYC2, which suppresses the expression of MYC2-targeted genes; After JA-Ile is recognized by a co-repressor complex of COI1 and JAZ, JAZs are ubiquitinated by an SFC complex containing COI1 and then degraded by 26S proteasome. The degradation of JAZs free MYC2 to active the expression of JA-response genes which include PMT, QPT, MPO and A622. Previous studies showed that NtCOI1, NtJAZs and NtMYC2 are required for nicotine formation. Therefore, discovering the new factor involved in JA signal pathway can be helpful for understanding the mechanism on transcriptional regulation of nicotine biosynthesis. In our previous work, the AIDP (AT-rich interactive domain containing protein) gene, one of NtJAZ1-interacted protein, was identified from the cDNA library of tobacco BY-2 cells by yeast two hybrid assay. Here, we continue to characterize the roles of AIDP in regulating nicotine biosynthesis. We first detected the interaction between AIDP and other proteins using luciferase complementation imaging assay and found that AIDP interacts with NtJAZ1, but not with MYC2, which is consistent with our previous result. AIDP was widely expressed in roots, stems, leaves and flowers in Nicotiana benthamiana, however, the AIDP transcripts is relatively higher in roots and stem than that in leaves and flowers. We also find that the expression of AIDP is not induced by JA in tobacco. Furthermore, overexpression of AIDP in Nicotiana benthamiana induced the expression of PMT, QPT, ODC and A622 more effectively than in wild type after MeJA treatment. Transient expression assays showed that the transcriptional activity of GAG fragment in promoter of PMT could be activated by AIDP. In addition, we found that overexpression of AIDP can up-regulate NtJAZ1 in Nicotiana benthamiana. Our results suggested that AIDP may act as a new JA signal component to regulate the nicotine formation.