Characterisation of AtPQL1, AtPQL2 and AtPQL3 as candidate voltage insensitive non-selective cation channels (vi-NSCCs).
| dc.contributor.advisor | Tester, Mark Alfred | en |
| dc.contributor.advisor | Roy, Stuart John | en |
| dc.contributor.advisor | Plett, Darren Craig | en |
| dc.contributor.author | Shearer, Monique Kirsten | en |
| dc.contributor.school | School of Agriculture, Food and Wine | en |
| dc.date.issued | 2013 | en |
| dc.description.abstract | Soil salinity is responsible for significant reductions in crop yield. The salinity tolerance of crops can be improved by minimising the amount of sodium ions (Na⁺) accumulating in the shoot. One hypothesis for reducing shoot Na⁺ accumulation is to minimise Na⁺ entering the plant via the root. Previous studies indicate that in most plants, the majority of Na⁺ entry into root cells is through voltage-insensitive non-selective cation channels (vi-NSCCs), however, the molecular identities of these channels are unclear. Recently two genes that belong to the PQL family were identified as putative vi-NSCCs in yeast. This project aims to functionally characterise three orthologous PQL genes from Arabidopsis thaliana (AtPQL1, AtPQL2 and AtPQL3) and investigate their role in Na⁺ entry into cells and into roots. Bioinformatic tools and in planta techniques were used to determine gene expression profiles, analyse protein sequences and determine the cellular and subcellular localisations of AtPQL1-3. The plasma membrane localisation of AtPQL1 and 2 agrees with the proposed function of vi-NSCCs as ion transport channels. Furthermore, the suggested role of vi-NSCCs in facilitating initial Na⁺ entry into the roots was supported by in silico expression profiles of AtPQL2 and 3 and by observations of reporter proteins driven by PQL promoters in root tissues. Heterologous expression of AtPQL1 in yeast resulted in yeast which were more salt sensitive than controls, suggesting a role in Na⁺ influx into cells. Furthermore, this sensitivity could be ameliorated by the addition of CaCl₂, (indicating Ca²⁺ inhibited the movement of Na⁺), an attribute which corresponds with known properties of vi-NSCCs. A number of transgenic Arabidopsis lines were generated to have altered expression of AtPQL1 to 3 and were then phenotypically analysed in hydroponics under a range of salt treatments. Results of these experiments proved largely inconclusive primarily because individual plants with significantly altered expression of AtPQL1, 2 and/or 3 could not be obtained. | en |
| dc.description.dissertation | Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2013 | en |
| dc.identifier.uri | http://hdl.handle.net/2440/83638 | |
| dc.provenance | Copyright material removed from digital thesis. See print copy in University of Adelaide Library for full text. | en |
| dc.subject | plant salinity tolerance; sodium transport; Arabidopsis | en |
| dc.title | Characterisation of AtPQL1, AtPQL2 and AtPQL3 as candidate voltage insensitive non-selective cation channels (vi-NSCCs). | en |
| dc.type | Thesis | en |
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