抄録
The nitrite transporter (CsNitr1-L) was cloned from cucumber. CsNitr1-L is localized in chloroplast envelopes. CsNitr1-L has an isoform (CsNitr1-S) having a core sequence overlapping with CsNitr1-L. CsNitr1-S is an efflux type nitrite transporter. L type may load nitrite into the chloroplast during nitrate assimilation. The CsNitr1-S is located in the plasma membrane and is anticipated to transport nitrite out of the cell. To better understand the function of the CsNitr1-S, transgenic tobacco lines overexpressing and suppressing the nitrite transporter were made by inserting the CsNitr1-S in the sense and antisense directions using Agrobacterium tumefaciens. The genetic and phenotypic traits of the transgenic plants were examined. The CsNitr1-S has a vital role in the germination stage of tobacco seeds. Other results have indicated some drought tolerance and early flowering of antisense plants. The relatedness of the nitrite transporter function with such phenotypes will be discussed.
