Isolation of PsPINs and PsAUX1 cDNAs Encoding Putative Auxin Efflux and Influx Carriers and/or Facilitators, Respectively, from Etiolated Epicotyls of an Agravitropic Pea (Pisum sativum L.) Mutant, ageotropum

Abstract

cDNAs containing the open reading frames of a putative auxin influx carrier and/or facilitator, PsAUX1 (Accession No. AB488680), and putative auxin efflux carriers and/or facilitators, PsPIN1, PsPIN2 and PsPIN3 (Accession No. AB488679, AB488681 and AB488678, respectively) from etiolated epicotyls of an agravitropic pea mutant, ageotropum, have been isolated. In PsPIN1 and PsPIN2, a few deduced amino acids were different between ageotropum and Alaska showing a normal gravitropic response. No insertion and deletion were observed in PsPIN1 and PsPIN2 of ageotropum compared with those of Alaska. However, PsAUX1 of ageotropum had additional amino acids at the C-terminus compared to that of Alaska. Phylogenetic analyses based on deduced amino acid sequences revealed that PsPIN1 of ageotropum and Alaska belonged to the same clade as MtPIN4, while PsPIN2 of ageotropum and Alaska belonged to a subclade including MtPIN3, BjPIN2, BjPIN3, SlPIN3 and SlPIN4. PsAUX1 of ageotropum with additional amino acids at C-terminus belonged to the same subclade as MiAUX1 and PtAUX1. PsPIN1, PsPIN2, PsPIN3 mRNAs in 3.5-day-old etiolated ageotropum pea seedlings were significantly expressed in the proximal and the distal sides of the first internode of epicotyls to cotyledon. Judging from the results of the structure and the expression of genes related to auxin polar transport, an abnormal gravitropic response of etiolated ageotropum pea seedlings might be related to post transcriptional regulation and translocation of PsAUX1, PsPIN1, PsPIN2 and PsPIN3 as well as the perturbation of auxin transport due to additional amino acids at C-terminus of PsAUX1. ©2012 Jpn. Soc. Biol. Sci.

Auxin Polar Transport is Essential for the Early Growth Stage of Etiolated Maize (Zea maysL. cv. Honey Bantam) Seedlings

“…Auxin polar transport was determined according to the method reported previously (Oka et al, 1995;Ueda et al, 1999Ueda et al, , 2000Ueda et al, , 2012Ueda et al, , 2013Hoshino et al, 2007) , American Radiolabeled Chemicals Inc., St. Louis, Mo.) was prepared in 1.5 ml Eppendorf tubes, and was incorporated into the apical or the basal side of the segments in the tube.…”

“…After the designated incubation period, the radioactivity on the opposite sides (1 to 2 mm) of the segment was directly determined using a liquid scintillation counter and auxin polar transport was shown by the radioactivity. This method has been considered to be suitable for the determination of auxin polar transport (Okada et al 1991;Oka et al 1995Oka et al , 1998Oka et al , 1999Ueda et al, 2012). Since radioactivities transported from basal to apical side of the segments were extremely small (Okada et al 1991;Oka et al 1995Oka et al , 1998Oka et al , 1999Ueda et al, 2012), only [ 14 C]IAA from the apical side of the segments was shown as a result.…”

“…In addition, auxin polar transport in etiolated epicotyls of agravitropic pea mutant, ageotropum, was also reduced to ca. 60% of that in etiolated Alaska pea epicotyls (Hoshino et al, 2007;Ueda et al, 2012).…”

“…Recent studies on auxin polar transport showed the presence of some membrane proteins controlling auxin polar transport which function as influx and efflux facilitators of auxin Ueda et al, 2011Ueda et al, , 2012, but it is obvious that PIN1 protein is essential for auxin polar transport (Okada et al, 1991;Gälweiler et al, 1998). The growth of rice coleoptiles and mesocotyls was significantly stimulated by exogenous application of brassinolide (Chon et al, 2000).…”

Close relationships between polar auxin transport and graviresponse in plants

“…Recently, we also succeeded in isolating novel cDNAs containing the complete open reading flame encoding putative auxin efflux carrier proteins, PsPIN1 (Chawla & DeMason ; Ueda et al . ), PsPIN2 (Hoshino et al . ; Ueda et al .…”