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Gao J, Wang F, Ranathunge K, Arruda AJ, Cawthray GR, Clode PL, He X, Leopold M, Roessner U, Rupasinghe T, Zhong H, Lambers H. Edaphic niche characterization of four Proteaceae reveals unique calcicole physiology linked to hyper-endemism of Grevillea thelemanniana. New Phytol 2020; 228:869-883. [PMID: 32726881 DOI: 10.1111/nph.16833] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 07/15/2020] [Indexed: 06/11/2023]
Abstract
Endemism and rarity have long intrigued scientists. We focused on a rare endemic and critically-endangered species in a global biodiversity hotspot, Grevillea thelemanniana (Proteaceae). We carried out plant and soil analyses of four Proteaceae, including G. thelemanniana, and combined these with glasshouse studies. The analyses related to hydrology and plant water relations as well as soil nutrient concentrations and plant nutrition, with an emphasis on sodium (Na) and calcium (Ca). The local hydrology and matching plant traits related to water relations partially accounted for the distribution of the four Proteaceae. What determined the rarity of G. thelemanniana, however, was its accumulation of Ca. Despite much higher total Ca concentrations in the leaves of the rare G. thelemanniana than in the common Proteaceae, very few Ca crystals were detected in epidermal or mesophyll cells. Instead of crystals, G. thelemanniana epidermal cell vacuoles contained exceptionally high concentrations of noncrystalline Ca. Calcium ameliorated the negative effects of Na on the very salt-sensitive G. thelemanniana. Most importantly, G. thelemanniana required high concentrations of Ca to balance a massively accumulated feeding-deterrent carboxylate, trans-aconitate. This is the first example of a calcicole species accumulating and using Ca to balance accumulation of an antimetabolite.
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Affiliation(s)
- Jingwen Gao
- School of Biological Sciences, University of Western Australia, Crawley, Perth, WA, 6009, Australia
- Environmental Resources and Soil Fertilizer Institute, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
| | - Feng Wang
- School of Biological Sciences, University of Western Australia, Crawley, Perth, WA, 6009, Australia
- Environmental Resources and Soil Fertilizer Institute, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
| | - Kosala Ranathunge
- School of Biological Sciences, University of Western Australia, Crawley, Perth, WA, 6009, Australia
| | - André J Arruda
- School of Biological Sciences, University of Western Australia, Crawley, Perth, WA, 6009, Australia
| | - Gregory R Cawthray
- School of Biological Sciences, University of Western Australia, Crawley, Perth, WA, 6009, Australia
| | - Peta L Clode
- School of Biological Sciences, University of Western Australia, Crawley, Perth, WA, 6009, Australia
- Centre for Microscopy, Characterisation and Analysis, University of Western Australia, Crawley, Perth, WA, 6009, Australia
| | - Xinhua He
- Center of Excellence for Soil Biology, College of Resources and Environment, Southwest University, Beibei, Chongqing, 400715, China
| | - Matthias Leopold
- UWA School of Agriculture and Environment, University of Western Australia, Crawley, Perth, WA, 6009, Australia
| | - Ute Roessner
- School of BioSciences, The University of Melbourne, Parkville, Melbourne, Vic, 3010, Australia
| | - Thusitha Rupasinghe
- School of BioSciences, The University of Melbourne, Parkville, Melbourne, Vic, 3010, Australia
| | - Hongtao Zhong
- School of Biological Sciences, University of Western Australia, Crawley, Perth, WA, 6009, Australia
| | - Hans Lambers
- School of Biological Sciences, University of Western Australia, Crawley, Perth, WA, 6009, Australia
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Xu B, Hrmova M, Gilliham M. High affinity Na + transport by wheat HKT1;5 is blocked by K . Plant Direct 2020; 4:e00275. [PMID: 33103046 PMCID: PMC7576878 DOI: 10.1002/pld3.275] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 09/21/2020] [Indexed: 05/11/2023]
Abstract
The wheat sodium transporters TmHKT1;5-A and TaHKT1;5-D are encoded by genes underlying the major shoot Na+ exclusion loci Nax2 and Kna1 from Triticum monococcum (Tm) and Triticum aestivum (Ta), respectively. In contrast to HKT2 transporters that have been shown to exhibit high affinity K+-dependent Na+ transport, HKT1 proteins have, with one exception, only been shown to catalyze low affinity Na+ transport and no K+ transport. Here, using heterologous expression in Xenopus laevis oocytes we uncover a novel property of HKT1 proteins, that both TmHKT1;5-A and TaHKT1;5-D encode dual (high and low) affinity Na+-transporters with the high-affinity component being abolished when external K+ is in excess of external Na+. Three-dimensional structural modeling suggested that, compared to Na+, K+ is bound more tightly in the selectivity filter region by means of additional van der Waals forces, which is likely to explain the K+ block at the molecular level. The low-affinity component for Na+ transport of TmHKT1;5-A had a lower K m than that of TaHKT1;5-D and was less sensitive to external K+. We propose that these properties contribute towards the improvements in shoot Na+-exclusion and crop plant salt tolerance following the introgression of TmHKT1;5-A into diverse wheat backgrounds.
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Affiliation(s)
- Bo Xu
- Australian Research Council Centre of Excellence in Plant Energy BiologyUniversity of AdelaideWaite Research PrecinctGlen OsmondSAAustralia
- School of Agriculture, Food and Wine, and Waite Research InstituteUniversity of AdelaideWaite Research PrecinctGlen OsmondSAAustralia
| | - Maria Hrmova
- School of Agriculture, Food and Wine, and Waite Research InstituteUniversity of AdelaideWaite Research PrecinctGlen OsmondSAAustralia
- School of Life ScienceHuaiyin Normal UniversityHuai’anChina
| | - Matthew Gilliham
- Australian Research Council Centre of Excellence in Plant Energy BiologyUniversity of AdelaideWaite Research PrecinctGlen OsmondSAAustralia
- School of Agriculture, Food and Wine, and Waite Research InstituteUniversity of AdelaideWaite Research PrecinctGlen OsmondSAAustralia
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Abstract
This article is a Commentary on https://doi.org/10.1111/nph.15955; https://doi.org/10.1111/nph.15713; https://doi.org/10.1111/nph.15773; https://doi.org/10.1111/nph.15864; https://doi.org/10.1111/nph.15862; https://doi.org/10.1111/nph.15852; https://doi.org/10.1111/nph.15758.
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Affiliation(s)
- Dale Sanders
- The John Innes CentreNorwich Research ParkNorwichNR4 7UHUK
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Chakraborty K, Bose J, Shabala L, Shabala S. Difference in root K+ retention ability and reduced sensitivity of K+-permeable channels to reactive oxygen species confer differential salt tolerance in three Brassica species. J Exp Bot 2016; 67:4611-25. [PMID: 27340231 PMCID: PMC4973732 DOI: 10.1093/jxb/erw236] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Brassica species are known to possess significant inter and intraspecies variability in salinity stress tolerance, but the cell-specific mechanisms conferring this difference remain elusive. In this work, the role and relative contribution of several key plasma membrane transporters to salinity stress tolerance were evaluated in three Brassica species (B. napus, B. juncea, and B. oleracea) using a range of electrophysiological assays. Initial root growth assay and viability staining revealed that B. napus was most tolerant amongst the three species, followed by B. juncea and B. oleracea At the mechanistic level, this difference was conferred by at least three complementary physiological mechanisms: (i) higher Na(+) extrusion ability from roots resulting from increased expression and activity of plasma membrane SOS1-like Na(+)/H(+) exchangers; (ii) better root K(+) retention ability resulting from stress-inducible activation of H(+)-ATPase and ability to maintain more negative membrane potential under saline conditions; and (iii) reduced sensitivity of B. napus root K(+)-permeable channels to reactive oxygen species (ROS). The last two mechanisms played the dominant role and conferred most of the differential salt sensitivity between species. Brassica napus plants were also more efficient in preventing the stress-induced increase in GORK transcript levels and up-regulation of expression of AKT1, HAK5, and HKT1 transporter genes. Taken together, our data provide the mechanistic explanation for differential salt stress sensitivity amongst these species and shed light on transcriptional and post-translational regulation of key ion transport systems involved in the maintenance of the root plasma membrane potential and cytosolic K/Na ratio as a key attribute for salt tolerance in Brassica species.
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Affiliation(s)
- Koushik Chakraborty
- Department of Plant Physiology, ICAR-Directorate of Groundnut Research, Junagadh, Gujarat-362 001, India School of Land and Food and Tasmanian Institute for Agriculture, University of Tasmania, Hobart, Private Bag 94, Tas 7001, Australia
| | - Jayakumar Bose
- School of Land and Food and Tasmanian Institute for Agriculture, University of Tasmania, Hobart, Private Bag 94, Tas 7001, Australia
| | - Lana Shabala
- School of Land and Food and Tasmanian Institute for Agriculture, University of Tasmania, Hobart, Private Bag 94, Tas 7001, Australia
| | - Sergey Shabala
- School of Land and Food and Tasmanian Institute for Agriculture, University of Tasmania, Hobart, Private Bag 94, Tas 7001, Australia
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Byrt CS, Xu B, Krishnan M, Lightfoot DJ, Athman A, Jacobs AK, Watson-Haigh NS, Plett D, Munns R, Tester M, Gilliham M. The Na(+) transporter, TaHKT1;5-D, limits shoot Na(+) accumulation in bread wheat. Plant J 2014; 80:516-26. [PMID: 25158883 DOI: 10.1111/tpj.12651] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 08/09/2014] [Accepted: 08/19/2014] [Indexed: 05/05/2023]
Abstract
Bread wheat (Triticum aestivum L.) has a major salt tolerance locus, Kna1, responsible for the maintenance of a high cytosolic K(+) /Na(+) ratio in the leaves of salt stressed plants. The Kna1 locus encompasses a large DNA fragment, the distal 14% of chromosome 4DL. Limited recombination has been observed at this locus making it difficult to map genetically and identify the causal gene. Here, we decipher the function of TaHKT1;5-D, a candidate gene underlying the Kna1 locus. Transport studies using the heterologous expression systems Saccharomyces cerevisiae and Xenopus laevis oocytes indicated that TaHKT1;5-D is a Na(+) -selective transporter. Transient expression in Arabidopsis thaliana mesophyll protoplasts and in situ polymerase chain reaction indicated that TaHKT1;5-D is localised on the plasma membrane in the wheat root stele. RNA interference-induced silencing decreased the expression of TaHKT1;5-D in transgenic bread wheat lines which led to an increase in the Na(+) concentration in the leaves. This indicates that TaHKT1;5-D retrieves Na(+) from the xylem vessels in the root and has an important role in restricting the transport of Na(+) from the root to the leaves in bread wheat. Thus, TaHKT1;5-D confers the essential salinity tolerance mechanism in bread wheat associated with the Kna1 locus via shoot Na(+) exclusion and is critical in maintaining a high K(+) /Na(+) ratio in the leaves. These findings show there is potential to increase the salinity tolerance of bread wheat by manipulation of HKT1;5 genes.
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Affiliation(s)
- Caitlin Siobhan Byrt
- CSIRO Plant Industry, Canberra, ACT, 2601, Australia; School of Agriculture, Food and Wine and Waite Research Institute, University of Adelaide, Waite Research Precinct, Glen Osmond, SA, 5064, Australia; Australian Research Council Centre of Excellence in Plant Cell Walls, University of Adelaide, Waite Research Precinct, Glen Osmond, SA, 5064, Australia; Australian Centre for Plant Functional Genomics, University of Adelaide, Waite Research Precinct, Glen Osmond, SA, 5064, Australia; Australian Research Council Centre of Excellence in Plant Energy Biology, University of Adelaide, Waite Research Precinct, Glen Osmond, SA, 5064, Australia
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Bonales-Alatorre E, Pottosin I, Shabala L, Chen ZH, Zeng F, Jacobsen SE, Shabala S. Differential activity of plasma and vacuolar membrane transporters contributes to genotypic differences in salinity tolerance in a Halophyte Species, Chenopodium quinoa. Int J Mol Sci 2013; 14:9267-85. [PMID: 23629664 PMCID: PMC3676782 DOI: 10.3390/ijms14059267] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 04/13/2013] [Accepted: 04/15/2013] [Indexed: 11/29/2022] Open
Abstract
Halophytes species can be used as a highly convenient model system to reveal key ionic and molecular mechanisms that confer salinity tolerance in plants. Earlier, we reported that quinoa (Chenopodium quinoa Willd.), a facultative C3 halophyte species, can efficiently control the activity of slow (SV) and fast (FV) tonoplast channels to match specific growth conditions by ensuring that most of accumulated Na+ is safely locked in the vacuole (Bonales-Alatorre et al. (2013) Plant Physiology). This work extends these finding by comparing the properties of tonoplast FV and SV channels in two quinoa genotypes contrasting in their salinity tolerance. The work is complemented by studies of the kinetics of net ion fluxes across the plasma membrane of quinoa leaf mesophyll tissue. Our results suggest that multiple mechanisms contribute towards genotypic differences in salinity tolerance in quinoa. These include: (i) a higher rate of Na+ exclusion from leaf mesophyll; (ii) maintenance of low cytosolic Na+ levels; (iii) better K+ retention in the leaf mesophyll; (iv) a high rate of H+ pumping, which increases the ability of mesophyll cells to restore their membrane potential; and (v) the ability to reduce the activity of SV and FV channels under saline conditions. These mechanisms appear to be highly orchestrated, thus enabling the remarkable overall salinity tolerance of quinoa species.
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Affiliation(s)
- Edgar Bonales-Alatorre
- School of Agricultural Science and Tasmanian Institute for Agriculture, University of Tasmania, Private Bag 54, Hobart, TAS 7001, Australia; E-Mails: (E.B.-A.); (L.S.); (F.Z.)
- University Centre for Biomedical Research, University of Colima, 28045 Colima, Mexico; E-Mail:
| | - Igor Pottosin
- University Centre for Biomedical Research, University of Colima, 28045 Colima, Mexico; E-Mail:
| | - Lana Shabala
- School of Agricultural Science and Tasmanian Institute for Agriculture, University of Tasmania, Private Bag 54, Hobart, TAS 7001, Australia; E-Mails: (E.B.-A.); (L.S.); (F.Z.)
| | - Zhong-Hua Chen
- School of Science and Health, University of Western Sydney, Richmond, NSW 2753, Australia; E-Mail:
| | - Fanrong Zeng
- School of Agricultural Science and Tasmanian Institute for Agriculture, University of Tasmania, Private Bag 54, Hobart, TAS 7001, Australia; E-Mails: (E.B.-A.); (L.S.); (F.Z.)
- College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Sven-Erik Jacobsen
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Højbakkegaard Allé 13, 2630 Taastrup, Denmark; E-Mail:
| | - Sergey Shabala
- School of Agricultural Science and Tasmanian Institute for Agriculture, University of Tasmania, Private Bag 54, Hobart, TAS 7001, Australia; E-Mails: (E.B.-A.); (L.S.); (F.Z.)
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Rivandi J, Miyazaki J, Hrmova M, Pallotta M, Tester M, Collins NC. A SOS3 homologue maps to HvNax4, a barley locus controlling an environmentally sensitive Na+ exclusion trait. J Exp Bot 2011; 62:1201-16. [PMID: 21047983 PMCID: PMC3022402 DOI: 10.1093/jxb/erq346] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2010] [Revised: 10/08/2010] [Accepted: 10/12/2010] [Indexed: 05/02/2023]
Abstract
Genes that enable crops to limit Na(+) accumulation in shoot tissues represent potential sources of salinity tolerance for breeding. In barley, the HvNax4 locus lowered shoot Na(+) content by between 12% and 59% (g(-1) DW), or not at all, depending on the growth conditions in hydroponics and a range of soil types, indicating a strong influence of environment on expression. HvNax4 was fine-mapped on the long arm of barley chromosome 1H. Corresponding intervals of ∼200 kb, containing a total of 34 predicted genes, were defined in the sequenced rice and Brachypodium genomes. HvCBL4, a close barley homologue of the SOS3 salinity tolerance gene of Arabidopsis, co-segregated with HvNax4. No difference in HvCBL4 mRNA expression was detected between the mapping parents. However, genomic and cDNA sequences of the HvCBL4 alleles were obtained, revealing a single Ala111Thr amino acid substitution difference in the encoded proteins. The known crystal structure of SOS3 was used as a template to obtain molecular models of the barley proteins, resulting in structures very similar to that of SOS3. The position in SOS3 corresponding to the barley substitution does not participate directly in Ca(2+) binding, post-translational modifications or interaction with the SOS2 signalling partner. However, Thr111 but not Ala111 forms a predicted hydrogen bond with a neighbouring α-helix, which has potential implications for the overall structure and function of the barley protein. HvCBL4 therefore represents a candidate for HvNax4 that warrants further investigation.
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Affiliation(s)
| | | | | | | | | | - N. C. Collins
- Australian Centre for Plant Functional Genomics, University of Adelaide, School of Agriculture Food and Wine, Hartley Grove, Urrbrae, PMB 1 Glen Osmond, SA 5064, Australia
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