Plant Peptides

Antisense Expression of the Peptide Transport Gene AtPTR2-B Delays Flowering and Arrests Seed Development in Transgenic Arabidopsis Plants

“…The reduction in AtPTR2-B expression correlated with marked effects on seed development and time of flowering. As suggested previously, peptide transport may play a nutritional role in seed development (Higgins and Payne, 1982). Thus, we examined seeds collected from wild-type and transgenic plants at different stages of development under the stereomicroscope.…”

“…However, several lines of evidence have demonstrated that peptide transport not only exists in plants, but may participate in central physiological processes such as nutrition. The finding of significant amounts of peptides and their putative transport among different organs, such as long distance transport via the phloem and xylem, suggest that there are peptide transporters present in the plasma membrane of these cells (Higgins and Payne, 1982). Moreover, plant cells presumably have different peptide transport systems to correspond to various peptides and their identified analogs, such as peptide-hormone conjugates (Klambt, 1960;Thurmann and Street, 1962;Bewley et al, 1986), phytotoxins (e.g.…”

“…It has been reported that isolated scutella from germinating barley (Hordeum vulgare) seeds have the ability to transport small peptides that are released from endosperm into the embryo, and are subsequently hydrolyzed to amino acids for growth (Sopanen et al, 1977;Higgins and Payne, 1978;Salmenkallio and Sopanen, 1989). Also, the isolation of plant peptide-conjugated hormones (Andreae et al, 1955;Winter and Thimann, 1966) implies the possible involvement of a peptide transport system in the regulation of plant hormone activity (Higgins and Payne, 1982). Peptide transport systems may be involved in the movement of such hormonepeptide conjugates within the plant.…”

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

“…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). However, there are few reports of peptide transport in different plant tissues, although proton-coupled peptide transport has been characterised in the plasma membrane of broad bean (Vicia faba) mature leaf mesophyll cells (Jamai et al, 1996), in A. thaliana roots , and in developing barley embryos (Sopanen et al, 1985b) in addition to the scutellum of the germinating barley grain (Hardy and Payne, 1992).…”

“…In plants, peptide transport is often associated with tissues showing rapid protein hydrolysis including germinating seeds and senescing leaves (Higgins and Payne, 1982). Peptide transport by the scutellum of the germinating barley (Hordeum vulgare) grain has been extensively characterised since dipeptide uptake by isolated embryos was first demonstrated 20 years ago (Higgins and Payne, 1977;Sopanen et al, 1977).…”