The \%E.coli\% trehase synthalose gene(\%otsA\%) was transferred into \%Nicotiana tabacum\% mediated by \%Agrobacterium\%, but the method for detecting low concentration of trehalose in transgenic plant was not available.The high performance liquid chromatograph(HPLC) with evaporative light\|scatting detector (ELSD) using water:methyl cyanide(1∶2\^6 v/v) as mobile phase was established in this work. An ODS column Zorbax RX\|SIL was employed. the trehalose detection limits of ELSD was 5mg/L. From the linear relationship between the logarithm of trehalose concentration and the logarithm of peak area, it was shown there was 14\^7μg\5(g FW)\+\{-1\} in transgenic plant. The data strongly confirmed that trehalose was responsible for the improved stress tolerance of the tobacco.
