NTR1 encodes a high affinity oligopeptide transporter in Arabidopsis

Cloning and functional characterisation of a peptide transporter expressed in the scutellum of barley grain during the early stages of germination

“…In contrast, AtPTR2-B was found to be expressed at high levels in several plant tissues, including young leaves, roots and germinating seeds (Song et al, 1996). In situ hybridization revealed AtPTR2-B mRNA to be localized to the embryo within the seedpod (Rentsch et al, 1995), although AtPTR2-B expression was also detected in the stem, flower and mature leaf, indicating that the peptide transporter was constitutively expressed in other plant tissues (Song et al, 1997). Although peptide transport is associated with rapid protein mobilisation especially seed storage protein proteolysis, leaf senescence and seed development, a more general role in the transport of organic nitrogen has been suggested (Higgins and Payne, 1982).…”

“…Complementation of the ptr2 mutant with an Arabidopsis thaliana cDNA library subsequently resulted in the isolation of a root-specific di-and tripeptide transporter AtPTR2-A . A second peptide transporter from A. thaliana (AtPTR2-B) was cloned independently by two groups, again employing a yeast complementation approach (Rentsch et al, 1995;Song et al, 1996). AtPTR2-B (NTR1) was first identified in a screen for histidine transporters although histidine transport rates in S. cerevisiae expressing NTR1 were too low to measure (Frommer et al, 1994).…”

“…AtPTR2-B (NTR1) was first identified in a screen for histidine transporters although histidine transport rates in S. cerevisiae expressing NTR1 were too low to measure (Frommer et al, 1994). AtPTR2-B expression was found in most plant tissues, with particularly high levels in the developing seedpods (Frommer et al, 1994;Rentsch et al, 1995;Song et al, 1996Song et al, , 1997. Transgenic A. thaliana with reduced levels of AtPTR2-B expression showed abnormal seed development, with fewer, larger seeds per silique than wild type plants, consistent with a role for peptide transport in seed development (Song et al, 1997).…”

Identification of a pollen‐specific sucrose transporter‐like proteinNtSUT3 from tobacco

“…To test for the function of NtSUT3, the cDNA was cloned as an XbaI/XhoI fragment into pMK195 [25] and the sucrose uptake-deficient yeast strain SUSY7 ura3 was transformed (Bfirkle, unpublished data). However, no difference in growth on sucrose could be detected when compared to control.…”

“…However, no difference in growth on sucrose could be detected when compared to control. To exclude that remaining flanking regions of the cDNA had a negative effect on expression in yeast, a PCR fragment lacking the small upstream translated region was cloned into pMKI95 and into pDR195 [25]. The plasmids differ in the promoter used to drive the expression of the cloned cDNA (ADH1 and PMA1 promoters, respectively).…”