高氮条件下烟叶中烟碱含量升高的分子机制解析OA

To explore the molecular mechanism of nicotine content increase in flue-cured tobacco under high nitrogen condition,a field experiment was conducted with three nitrogen levels of high,normal and low.Total nitrogen and nicotine contents in tobacco leaves were measured,and transcriptome analysis was per-formed on the groups with significant nicotine difference.The results showed that the nicotine content increased with the increase of nitrogen application level,a significant difference was observed between high and low ni-trogen treatment groups,and the transcriptome analysis was performed between the two groups.The results showed that elevated nitrogen affected nicotine metabolism through three main pathways.The first pathway was to boost pyrrole ring formation by up-regulating the experssion of key rate-limiting genes NtODC and NtPRO2 in the nicotine pyrrole ring synthesis pathway.The second pathway was to enhance the cycle of pyridine nucle-otide and promote pyridine ring synthesis by up-regulating the expression of nicotinic acid nucleotide cycle key gene ISN1.The third pathway was to reduce nicotine degradation and increase its accumulation by down-regu-lating the nicotine demethylase-related gene Nitab4.5_0015193g00 10.Plant hormone signal transduction path-ways played regulation functiuon in nicotine synthesis,among which,the TCH4 gene in the brassinosteroid(BR)pathway and the PR-1 gene in salicylic acid(SA)pathway playedimportant roles.These findings pro-vided a theoretical basis for understanding how nitrogen levels affecting nicotine synthesis and a new approach for exploring the link between phytohormones and nicotine accumulation.