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A comparative study of salt tolerance parameters in 11 wild relatives of Arabidopsis thaliana.

Orsini F, D'Urzo MP, Inan G, Serra S, Oh DH, Mickelbart MV, Consiglio F, Li X, Jeong JC, Yun DJ, Bohnert HJ, Bressan RA, Maggio A - J. Exp. Bot. (2010)

Bottom Line: In a search for candidates to begin to understand, through genetic analyses, the biological bases of salt tolerance, 11 wild relatives of Arabidopsis thaliana were compared: Barbarea verna, Capsella bursa-pastoris, Hirschfeldia incana, Lepidium densiflorum, Malcolmia triloba, Lepidium virginicum, Descurainia pinnata, Sisymbrium officinale, Thellungiella parvula, Thellungiella salsuginea (previously T. halophila), and Thlaspi arvense.Only T. parvula revealed a true halophytic habitus, comparable to the better studied Thellungiella salsuginea.Major differences in growth, water transport properties, and ion accumulation are observed and discussed to describe the distinctive traits and physiological responses that can now be studied genetically in salt stress research.

View Article: PubMed Central - PubMed

Affiliation: Department of Agro-environmental Sciences and Technologies, University of Bologna, Viale Fanin 44, I-40127 Bologna, Italy.

ABSTRACT
Salinity is an abiotic stress that limits both yield and the expansion of agricultural crops to new areas. In the last 20 years our basic understanding of the mechanisms underlying plant tolerance and adaptation to saline environments has greatly improved owing to active development of advanced tools in molecular, genomics, and bioinformatics analyses. However, the full potential of investigative power has not been fully exploited, because the use of halophytes as model systems in plant salt tolerance research is largely neglected. The recent introduction of halophytic Arabidopsis-Relative Model Species (ARMS) has begun to compare and relate several unique genetic resources to the well-developed Arabidopsis model. In a search for candidates to begin to understand, through genetic analyses, the biological bases of salt tolerance, 11 wild relatives of Arabidopsis thaliana were compared: Barbarea verna, Capsella bursa-pastoris, Hirschfeldia incana, Lepidium densiflorum, Malcolmia triloba, Lepidium virginicum, Descurainia pinnata, Sisymbrium officinale, Thellungiella parvula, Thellungiella salsuginea (previously T. halophila), and Thlaspi arvense. Among these species, highly salt-tolerant (L. densiflorum and L. virginicum) and moderately salt-tolerant (M. triloba and H. incana) species were identified. Only T. parvula revealed a true halophytic habitus, comparable to the better studied Thellungiella salsuginea. Major differences in growth, water transport properties, and ion accumulation are observed and discussed to describe the distinctive traits and physiological responses that can now be studied genetically in salt stress research.

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Representation summarizing the various parameters that have been recorded in this study. Different species are compared based on their relative ability to express pathways and phenotypes that support extremophile behaviour and success in adaptation. The species can be sorted in such a way that indicated T. parvula and T. salsuginea as the most successful species.
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fig11: Representation summarizing the various parameters that have been recorded in this study. Different species are compared based on their relative ability to express pathways and phenotypes that support extremophile behaviour and success in adaptation. The species can be sorted in such a way that indicated T. parvula and T. salsuginea as the most successful species.

Mentions: The ability of plants to control cytoplasmic Na+ accumulation against vacuolar compartmentation is critical for determining salt tolerance in both glycophytes and halophytes (Hasegawa et al., 2000; Munns, 2002; Parks et al., 2002). However, the occurrence of a relative greater variation among halophytic respect to glycophytic species (Greenway and Munns, 1980; Yokoi et al., 2002; Tester and Davenport, 2003) suggests that, in the former, additional salt tolerance effectors may exist (Volkov et al., 2004; Kant et al., 2006; Volkov and Amtmann, 2006). Minimizing bypass flow and other traits such as reduced transpiration have been proposed to contribute to the superior performance of halophytes under highly saline conditions (Flowers et al., 1977, 1986; Yeo et al., 1987; Lovelock and Ball, 2002). For instance, salt cress develops a double endodermis and it employs reduced transpiration [also observed in all halophytic species under assessment (Fig. 7)], with both characters contributing in restricting Na+ accumulation by reducing bypass flow (Inan et al., 2004). Uncertainties about fundamental mechanisms of Na+ uptake/distribution/compartmentation within plants, as well as on Na+/K+ selectivity, gradually become comprehensible by comparative analysis of Arabidopsis versus ARMS and/or other halophytes (Flowers and Colmer, 2008). Na+ influxes in halophytes are significantly lower than those found for Arabidopsis (Fig. 9). However, Na+ uptake in T. salsuginea seems to be mediated by a voltage-dependent channel similar to the glycophytic process (Demidchik and Maathuis, 2007). In addition, reduction in the expression of the SOS1 Na+/H+ transport system changed Thellungiella that normally can grow in seawater-strength sodium chloride solutions into a plant as sensitive to Na+ as Arabidopsis (Oh et al., 2009) suggesting that halophytes and glycophytes share similar transporters and regulatory networks, but that different set points exist (Flowers and Colmer, 2008). One such set point seems to be basal gene expression strength and timing of expression in salt cress (Gong et al., 2005; Oh et al., 2009). Reduced Na+ flux has been confirmed in salt cress and found to exist in T. parvula (Fig. 10). However, behaviours distinguishing T. salsuginea and T. parvula regarding K+ transport and accumulation have been observed, possibly pointing towards several mechanisms for establishing ion homeostasis to cope with ion toxicity in halophytes (Volkov and Amtmann, 2006). Upon salinization, the larger K+ availability in T. parvula compared with both A. thaliana and T. salsuginea (Fig. 10) was correlated with a higher salinity tolerance (Figs 1–3). A representation summarizing the various parameters that have been recorded in this study is presented in Fig. 11.


A comparative study of salt tolerance parameters in 11 wild relatives of Arabidopsis thaliana.

Orsini F, D'Urzo MP, Inan G, Serra S, Oh DH, Mickelbart MV, Consiglio F, Li X, Jeong JC, Yun DJ, Bohnert HJ, Bressan RA, Maggio A - J. Exp. Bot. (2010)

Representation summarizing the various parameters that have been recorded in this study. Different species are compared based on their relative ability to express pathways and phenotypes that support extremophile behaviour and success in adaptation. The species can be sorted in such a way that indicated T. parvula and T. salsuginea as the most successful species.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2921208&req=5

fig11: Representation summarizing the various parameters that have been recorded in this study. Different species are compared based on their relative ability to express pathways and phenotypes that support extremophile behaviour and success in adaptation. The species can be sorted in such a way that indicated T. parvula and T. salsuginea as the most successful species.
Mentions: The ability of plants to control cytoplasmic Na+ accumulation against vacuolar compartmentation is critical for determining salt tolerance in both glycophytes and halophytes (Hasegawa et al., 2000; Munns, 2002; Parks et al., 2002). However, the occurrence of a relative greater variation among halophytic respect to glycophytic species (Greenway and Munns, 1980; Yokoi et al., 2002; Tester and Davenport, 2003) suggests that, in the former, additional salt tolerance effectors may exist (Volkov et al., 2004; Kant et al., 2006; Volkov and Amtmann, 2006). Minimizing bypass flow and other traits such as reduced transpiration have been proposed to contribute to the superior performance of halophytes under highly saline conditions (Flowers et al., 1977, 1986; Yeo et al., 1987; Lovelock and Ball, 2002). For instance, salt cress develops a double endodermis and it employs reduced transpiration [also observed in all halophytic species under assessment (Fig. 7)], with both characters contributing in restricting Na+ accumulation by reducing bypass flow (Inan et al., 2004). Uncertainties about fundamental mechanisms of Na+ uptake/distribution/compartmentation within plants, as well as on Na+/K+ selectivity, gradually become comprehensible by comparative analysis of Arabidopsis versus ARMS and/or other halophytes (Flowers and Colmer, 2008). Na+ influxes in halophytes are significantly lower than those found for Arabidopsis (Fig. 9). However, Na+ uptake in T. salsuginea seems to be mediated by a voltage-dependent channel similar to the glycophytic process (Demidchik and Maathuis, 2007). In addition, reduction in the expression of the SOS1 Na+/H+ transport system changed Thellungiella that normally can grow in seawater-strength sodium chloride solutions into a plant as sensitive to Na+ as Arabidopsis (Oh et al., 2009) suggesting that halophytes and glycophytes share similar transporters and regulatory networks, but that different set points exist (Flowers and Colmer, 2008). One such set point seems to be basal gene expression strength and timing of expression in salt cress (Gong et al., 2005; Oh et al., 2009). Reduced Na+ flux has been confirmed in salt cress and found to exist in T. parvula (Fig. 10). However, behaviours distinguishing T. salsuginea and T. parvula regarding K+ transport and accumulation have been observed, possibly pointing towards several mechanisms for establishing ion homeostasis to cope with ion toxicity in halophytes (Volkov and Amtmann, 2006). Upon salinization, the larger K+ availability in T. parvula compared with both A. thaliana and T. salsuginea (Fig. 10) was correlated with a higher salinity tolerance (Figs 1–3). A representation summarizing the various parameters that have been recorded in this study is presented in Fig. 11.

Bottom Line: In a search for candidates to begin to understand, through genetic analyses, the biological bases of salt tolerance, 11 wild relatives of Arabidopsis thaliana were compared: Barbarea verna, Capsella bursa-pastoris, Hirschfeldia incana, Lepidium densiflorum, Malcolmia triloba, Lepidium virginicum, Descurainia pinnata, Sisymbrium officinale, Thellungiella parvula, Thellungiella salsuginea (previously T. halophila), and Thlaspi arvense.Only T. parvula revealed a true halophytic habitus, comparable to the better studied Thellungiella salsuginea.Major differences in growth, water transport properties, and ion accumulation are observed and discussed to describe the distinctive traits and physiological responses that can now be studied genetically in salt stress research.

View Article: PubMed Central - PubMed

Affiliation: Department of Agro-environmental Sciences and Technologies, University of Bologna, Viale Fanin 44, I-40127 Bologna, Italy.

ABSTRACT
Salinity is an abiotic stress that limits both yield and the expansion of agricultural crops to new areas. In the last 20 years our basic understanding of the mechanisms underlying plant tolerance and adaptation to saline environments has greatly improved owing to active development of advanced tools in molecular, genomics, and bioinformatics analyses. However, the full potential of investigative power has not been fully exploited, because the use of halophytes as model systems in plant salt tolerance research is largely neglected. The recent introduction of halophytic Arabidopsis-Relative Model Species (ARMS) has begun to compare and relate several unique genetic resources to the well-developed Arabidopsis model. In a search for candidates to begin to understand, through genetic analyses, the biological bases of salt tolerance, 11 wild relatives of Arabidopsis thaliana were compared: Barbarea verna, Capsella bursa-pastoris, Hirschfeldia incana, Lepidium densiflorum, Malcolmia triloba, Lepidium virginicum, Descurainia pinnata, Sisymbrium officinale, Thellungiella parvula, Thellungiella salsuginea (previously T. halophila), and Thlaspi arvense. Among these species, highly salt-tolerant (L. densiflorum and L. virginicum) and moderately salt-tolerant (M. triloba and H. incana) species were identified. Only T. parvula revealed a true halophytic habitus, comparable to the better studied Thellungiella salsuginea. Major differences in growth, water transport properties, and ion accumulation are observed and discussed to describe the distinctive traits and physiological responses that can now be studied genetically in salt stress research.

Show MeSH