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Meharg C, Khan B, Norton G, Deacon C, Johnson D, Reinhardt R, Huettel B, Meharg AA. Trait-directed de novo population transcriptome dissects genetic regulation of a balanced polymorphism in phosphorus nutrition/arsenate tolerance in a wild grass, Holcus lanatus. THE NEW PHYTOLOGIST 2014; 201:144-154. [PMID: 24102375 DOI: 10.1111/nph.12491] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 08/12/2013] [Indexed: 05/03/2023]
Abstract
The aim of this study was to characterize the transcriptome of a balanced polymorphism, under the regulation of a single gene, for phosphate fertilizer responsiveness/arsenate tolerance in wild grass Holcus lanatus genotypes screened from the same habitat. De novo transcriptome sequencing, RNAseq (RNA sequencing) and single nucleotide polymorphism (SNP) calling were conducted on RNA extracted from H. lanatus. Roche 454 sequencing data were assembled into c. 22,000 isotigs, and paired-end Illumina reads for phosphorus-starved (P-) and phosphorus-treated (P+) genovars of tolerant (T) and nontolerant (N) phenotypes were mapped to this reference transcriptome. Heatmaps of the gene expression data showed strong clustering of each P+/P- treated genovar, as well as clustering by N/T phenotype. Statistical analysis identified 87 isotigs to be significantly differentially expressed between N and T phenotypes and 258 between P+ and P- treated plants. SNPs and transcript expression that systematically differed between N and T phenotypes had regulatory function, namely proteases, kinases and ribonuclear RNA-binding protein and transposable elements. A single gene for arsenate tolerance led to distinct phenotype transcriptomes and SNP profiles, with large differences in upstream post-translational and post-transcriptional regulatory genes rather than in genes directly involved in P nutrition transport and metabolism per se.
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Affiliation(s)
- Caroline Meharg
- Institute for Global Food Security, Queen's University Belfast, David Keir Building, Malone Road, Belfast, BT9 5BN, UK
| | - Bayezid Khan
- Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen, AB24 3UU, UK
| | - Gareth Norton
- Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen, AB24 3UU, UK
| | - Claire Deacon
- Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen, AB24 3UU, UK
| | - David Johnson
- Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen, AB24 3UU, UK
| | - Richard Reinhardt
- Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829, Köln, Germany
| | - Bruno Huettel
- Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829, Köln, Germany
| | - Andrew A Meharg
- Institute for Global Food Security, Queen's University Belfast, David Keir Building, Malone Road, Belfast, BT9 5BN, UK
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Logoteta B, Xu XY, Macnair MR, McGrath SP, Zhao FJ. Arsenite efflux is not enhanced in the arsenate-tolerant phenotype of Holcus lanatus. THE NEW PHYTOLOGIST 2009; 183:340-348. [PMID: 19402874 DOI: 10.1111/j.1469-8137.2009.02841.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Arsenate tolerance in Holcus lanatus is achieved mainly through suppressed arsenate uptake. We recently showed that plant roots can rapidly efflux arsenite to the external medium. Here, we tested whether arsenite efflux is a component of the adaptive arsenate tolerance in H. lanatus. Tolerant and nontolerant phenotypes were exposed to different arsenate concentrations with or without phosphate for 24 h, and arsenic (As) speciation was determined in nutrient solutions, roots and xylem sap. At the same arsenate exposure concentration, the nontolerant phenotype took up more arsenate and effluxed more arsenite than the tolerant phenotype. However, arsenite efflux was proportional to arsenate uptake and was not enhanced in the tolerant phenotype. Within 2-24 h, most (80-100%) of the arsenate taken up was effluxed to the medium as arsenite. About 86-95% of the As in the roots and majority of the As in xylem sap (c. 66%) was present as arsenite, and there were no significant differences between phenotypes. Arsenite efflux is not adaptively enhanced in the tolerant phenotype H. lanatus, but it could be a basal tolerance mechanism to greatly decrease cellular As burden in both phenotypes. Tolerant and nontolerant phenotypes had a similar capacity to reduce arsenate in roots.
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Affiliation(s)
- B Logoteta
- Rothamsted Research, Harpenden, Herts AL5 2JQ, UK
- Dipartimento di Biotecnologie per il Monitoraggio Agro-alimentare ed Ambientale (BIOMAA), Universita' Mediterranea di Reggio Calabria, Facolta' di Agraria - Loc. Feo di Vito, I-89060 Reggio Calabria, Italia
| | - X Y Xu
- Rothamsted Research, Harpenden, Herts AL5 2JQ, UK
- Tianjin Agriculture University, Tianjin 300384, China; and
| | - M R Macnair
- School of Biosciences, University of Exeter, Exeter EX4 4PS, UK
| | - S P McGrath
- Rothamsted Research, Harpenden, Herts AL5 2JQ, UK
| | - F J Zhao
- Rothamsted Research, Harpenden, Herts AL5 2JQ, UK
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