Abstract
Nicotine, a major alkaloid in tobacco plants, is produced in tobacco roots and transported to the vacuole of leaves for storage. A low nicotine mutant (nic1nic2) is defective in nicotine biosynthesis and accumulation very low levels of nicotine. By differential display technique, we found that two highly homologous genes (NtMATE1, NtMATE2) are expressed at very low levels in nic1nic2 compared to wild type. Function of MATE-type transporters is largely unknown in plants. We speculate that NtMATE1/2 participate in nicotine transport, because expression of these genes is coordinately regulated with bona fide nicotine biosynthesis genes. We are currently investigating the intercellular localization of NtMATE1/2 and their nicotine transport activity using NtMATE1-expressing cultured BY-2 cells. We also plan to analyze accumulation of nicotine in the NtMATE1-suppressed and -overexpressed transgenic tobacco plants.
