AUX1 promotes lateral root formation by facilitating indole-3-acetic acid distribution between sink and source tissues in the Arabidopsis seedling

被引:411
作者
Marchant, A
Bhalerao, R
Casimiro, I
Eklöf, J
Casero, PJ
Bennett, M
Sandberg, G [4 ]
机构
[1] Univ Nottingham, Sch Biosci, Plant Sci Div, Nottingham NG7 2RD, England
[2] Univ Extremadura, Dept Ciencias Morfol, Badajoz, Spain
[3] Univ Extremadura, Dept Biol Celular & Anim, Badajoz, Spain
[4] Swedish Univ Agr Sci, Dept Forest Genet & Plant Physiol, S-90183 Umea, Sweden
关键词
D O I
10.1105/tpc.010354
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Arabidopsis root architecture is regulated by shoot-derived signals such as nitrate and auxin. We report that mutations in the putative auxin influx carrier AUX1 modify root architecture as a result of the disruption in hormone transport between indole-3-acetic acid (IAA) source and sink tissues. Gas chromatography-selected reaction monitoring-mass spectrometry measurements revealed that the aux1 mutant exhibited altered IAA distribution in young leaf and root tissues, the major IAA source and sink organs, respectively, in the developing seedling. Expression studies using the auxin-inducible reporter IAA2::uidA revealed that AUX1 facilitates IAA loading into the leaf vascular transport system. AUX1 also facilitates IAA unloading in the primary root apex and developing lateral root primordium. Exogenous application of the synthetic auxin 1-naphthylacetic acid is able to rescue the aux1 lateral root phenotype, implying that root auxin levels are suboptimal for lateral root primordium initiation in the mutant.
引用
收藏
页码:589 / 597
页数:9
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