Fig. 4
ABCB6 localizes to the plasma membrane and promotes auxin transport together with ABCB20. a Schematic diagram of plant sections used in inflorescence stem polar auxin transport assays. Stem segments of 2.5 cm were dissected as illustrated and used in the auxin reporter pDR5:GUS experiments and radioactive IAA experiments (b, c). b pDR5:GUS reporter activity was imaged in response to IAA application to the apical side of the segment. amiR1334 shows reduction of pDR5:GUS activity at the basal side. Section numbers correspond to the section positions shown in (a). c Basipetal and acropetal radiolabeled IAA ([14C]IAA) transport in Arabidopsis inflorescence stems. Apical 2.5-cm stem segments were treated with [14C]IAA for 4 h. Negative indicates samples not treated with [14C]IAA. CPM stands for counts per minute. n = 10–15, **P < 0.01, Student’s t-test. d [3H]IAA export from Arabidopsis leaf mesophyll protoplasts. n = 4, *P < 0.05, Welch’s t-test. e, f ABCB6 plasma membrane localization shown by p35S:ABCB6-YFP in Arabidopsis protoplast (e) and tobacco leaves (f). Yellow indicates for ABCB6-YFP fluorescence, red indicates for FM4-64 (e) or the plasma membrane marker AHA2-RFP (f). Scale bar, 5 μm (e) and 10 μm (f). g Expression pattern of pABCB6:GFP-GUS. Presented are 7- and 15-day-old seedlings. Scale bar, 1 mm for shoot and cotyledon, 0.1 mm for root tip. h pABCB6:NLS-YFP plants presenting NLS-YFP signal (yellow) in the root vascular tissues. Propidium iodide in red. Scale bar, 10 μm. i Expression pattern of pABCB20:GFP-GUS. Presented are 7- and 15-day-old seedlings. Scale bar, 1 mm for shoot and cotyledon, 0.1 mm for root tip
