Overexpression of NfsI in switchgrass improved the uptake
rate of 2,4-DNT
A liquid culture system was employed to examine uptake of 2,4-DNT by theNfsI overexpressing transgenic switchgrass plants. We chose
20 mg·L-12,4-DNT as the initial concentration based on the previous 2,4-DNT
tolerance analysis in wild type switchgrass. The culture medium
containing 20 mg·L-1 2,4-DNT without switchgrass
plants was used as a blank control. After 2 days, the control
switchgrass plants removed 24.9% of 2,4-DNT from the culture medium,
whereas NfsI_OE-02 and -14
transgenic lines removed 66.7% and 64.3% of 2,4-DNT from the culture
medium, respectively (Fig. 5A ). After 6 days,
the control switchgrass plants
removed 56.3% of 2,4-DNT from the culture medium
(Fig. 5A ). However, they
displayed serious symptoms of toxicity including growth stunting and
leaf wilting, which prevented further removal of 2,4-DNT
(Fig. S5A ). In contrast,
94.1% of 2,4-DNT was taken up by the transgenic switchgrass plants
after 6 days (Fig. 5A ). Moreover, their growth was barely
affected by 2,4-DNT treatment (Fig. S5B ). In addition, we
compared the uptake rate of DNTS between control and transgenic
switchgrass plants (Fig. 5B ). Our results showed that
overexpressing NfsI in switchgrass did not improve the uptake
rate of DNTS.