Temporal root responses in Arabidopsis thaliana L. to chromate reveal structural and regulatory mechanisms involving the SOLITARY ROOT/IAA14 repressor for maintenance of identity meristem genes
- 95 Downloads
The Arabidopsis root system is modified in response to stress generated by high concentrations of nonessential ions such as chromate [Cr(VI)]. In this work, the distribution of auxin and its transporters PIN1 and PIN7, as well as the expression of genes that maintain the identity of the root meristem, were analyzed in Arabidopsis thaliana wild-type (WT) seedlings and in a mutant affected in the SOLITARY ROOT (SLR1/IAA14) locus, which is required for root response to Cr(VI). We show that primary root inhibition, auxin transporter levels, and expression of meristem identity genes were maintained in the slr-1 mutants but not in WT plants in response to Cr(VI) in a time- and concentration-dependent manner. Notably, the outermost single cell layer of the lateral root cap, which normally dies and tends to peel off, remains viable and increases in size following exposure of WT plants, but not slr-1 mutants, to Cr(VI). Our results suggest that (1) the primary root tip senses Cr(VI), (2) the external lateral root cap may play a protective role during Cr(VI) exposure, and (3) Cr(VI) impacts cell division in root meristems via auxin redistribution and SLR1/IAA14 function, influencing the expression of root meristem genes.
KeywordsChromate Root growth Meristem identity Auxin
Funding was provided by Conacyt with Grant No. CB-2011-01-169769.
- Arnaud C, Bonnot C, Desnos T, Nussaume L (2010) The root cap at the forefront. Criti Rev Biol 333:335–343Google Scholar
- Epstein E, Bloom AJ (2004) Mineral nutrition of plants: principles and perspectives, 2 edn. Sinnauer editorial, Sunderland, 400 ppGoogle Scholar
- López-Bucio J, Ortiz-Castro R, Ruíz-Herrera LF, Juárez CV, Hernández-Madrigal F, Carreón-Abud Y, Martínez-Trujillo M (2015) Chromate induces adventitious root formation via auxin signalling and SOLITARY-ROOT/IAA14 gene function in Arabidopsis thaliana. Biometals 28:353–365CrossRefPubMedGoogle Scholar
- Lucas M, Swarup R, Paponov IA, Swarup K, Casimiro I, Lake D, Peret B, Zappala S, Mairhofer S, Whitword M, Wang J, Ljung K, Marchant A, Sandberg G, Holdsworth MJ, Palme K, Pridmore T, Mooney S, Bennett MJ (2011) SHORT-ROOT regulates primary, lateral, and adventitious root development in Arabidopsis. Plant Physiol 155:384–398CrossRefPubMedGoogle Scholar
- Martínez-Trujillo M, Méndez-Bravo A, Ortiz-Castro R, Hernández-Madrigal F, Ibarra-Laclette E, Ruiz-Herrera LF, Long TA, Cervantes C, Herrera-Estrella L, López-Bucio J (2014) Chromate alters root system architecture and activates expression of genes involved in iron homeostasis and signaling in Arabidopsis thaliana. Plant Mol Biol 86:35–50CrossRefPubMedGoogle Scholar
- McGrath SP, Smith S (1990) Chromium and nickel. In: Alloway BJ (ed) Heavy Metals in soils. Wiley, New York, pp 125–150Google Scholar
- Muto H, Watahiki MK, Nakamoto D, Kinjo M, Yamamoto KT (2007) Specificity and similarity of functions of the Aux/IAA genes in auxin signaling of Arabidopsis revealed by promoter-exchange experiments among MSG2/IAA19, AXR2/IAA7, and SLR/IAA14. Plant Physiol 144:187–196CrossRefPubMedPubMedCentralGoogle Scholar
- Péret B, Swarup K, Ferguson A, Seth M, Yang Y, Dhondt S, James N, Casimiro I, Perry P, Syed A, Yang H, Reemmer J, Venison E, Howells C, Prerez-Amador MA, Yung J, Alonso J, Beemster GTS, Laplaze L, Murphy A, Bennett MJ, Nielsen E, Swarup R (2012) AUX/LAX genes encode a family of auxin influx transporters that perform distinct functions during Arabidopsis development. Plant Cell 24:2874–2885CrossRefPubMedPubMedCentralGoogle Scholar
- Scheres B, Benfey P, Dolan L (2002) Root development. The Arabidopsis Book. Am Soc Plant Biol 1:e0101Google Scholar