Silencing of PMT expression caused a surge of anatabine accumulation in tobacco

Drastic increase of anatabine levels was observed in tobacco plants with markedly reduced nicotine concentrations through RNA silencing approaches. By down-regulation of PMT through three kinds of RNA silencing approaches, the nicotine levels decreased accordingly. In lines with slight and moderate reduction of nicotine levels, no anticipated negative linear correlation was found between anatabine and nicotine content. In lines with nicotine levels lower than 2.7 mg/g, drastic elevation of anatabine levels was found. Transcriptional levels of QPRT were unaffected in tobacco lines with surged anatabine levels. This report of an intriguing mutual relationship of nicotine and anatabine sheds new light on mechanisms between metabolic regulations in plants, and reconfirms complexity of metabolic networks.