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New ABA-hypersensitive Arabidopsis mutants are affected in loci mediating responses to water deficit and Dickeya dadantii infection.

Plessis A, Cournol R, Effroy D, Silva Pérez V, Botran L, Kraepiel Y, Frey A, Sotta B, Cornic G, Leung J, Giraudat J, Marion-Poll A, North HM - PLoS ONE (2011)

Bottom Line: The has2 mutant also exhibited increased germination inhibition by ABA, while ABA-inducible gene expression was not modified on dehydration, indicating the mutated gene affects early ABA-signalling responses that do not modify transcript levels.In contrast, weak ABA-hypersensitivity relative to mutant developmental phenotypes suggests that HAS3 regulates drought responses by both ABA-dependent and independent pathways. has1 mutant phenotypes were only apparent on stress or ABA treatments, and included reduced water loss on rapid dehydration.In contrast to has2, has1 exhibited only minor changes in susceptibility to Dickeya dadantii despite similar ABA-hypersensitivity, indicating that crosstalk between ABA responses to this pathogen and drought stress can occur through more than one point in the signalling pathway.

View Article: PubMed Central - PubMed

Affiliation: Institut Jean-Pierre Bourgin, UMR1318, INRA, AgroParisTech, Versailles, France.

ABSTRACT
On water deficit, abscisic acid (ABA) induces stomata closure to reduce water loss by transpiration. To identify Arabidopsis thaliana mutants which transpire less on drought, infrared thermal imaging of leaf temperature has been used to screen for suppressors of an ABA-deficient mutant (aba3-1) cold-leaf phenotype. Three novel mutants, called hot ABA-deficiency suppressor (has), have been identified with hot-leaf phenotypes in the absence of the aba3 mutation. The defective genes imparted no apparent modification to ABA production on water deficit, were inherited recessively and enhanced ABA responses indicating that the proteins encoded are negative regulators of ABA signalling. All three mutants showed ABA-hypersensitive stomata closure and inhibition of root elongation with little modification of growth and development in non-stressed conditions. The has2 mutant also exhibited increased germination inhibition by ABA, while ABA-inducible gene expression was not modified on dehydration, indicating the mutated gene affects early ABA-signalling responses that do not modify transcript levels. In contrast, weak ABA-hypersensitivity relative to mutant developmental phenotypes suggests that HAS3 regulates drought responses by both ABA-dependent and independent pathways. has1 mutant phenotypes were only apparent on stress or ABA treatments, and included reduced water loss on rapid dehydration. The HAS1 locus thus has the required characteristics for a targeted approach to improving resistance to water deficit. In contrast to has2, has1 exhibited only minor changes in susceptibility to Dickeya dadantii despite similar ABA-hypersensitivity, indicating that crosstalk between ABA responses to this pathogen and drought stress can occur through more than one point in the signalling pathway.

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Related in: MedlinePlus

Hot leaf phenotype of has aba3-1 and has mutants visualised by thermal imaging.False colour infrared image of the temperature of drought stressed plants. (A–C) leaf temperature of has aba3-1 mutants compared to wild-type (WT) and the aba3-1 mutant. (D–F) leaf temperature of has mutants compared to wild-type. Plants were 14 days old and watering had been withheld for 2 days. Scale indicates temperature (°C).
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pone-0020243-g001: Hot leaf phenotype of has aba3-1 and has mutants visualised by thermal imaging.False colour infrared image of the temperature of drought stressed plants. (A–C) leaf temperature of has aba3-1 mutants compared to wild-type (WT) and the aba3-1 mutant. (D–F) leaf temperature of has mutants compared to wild-type. Plants were 14 days old and watering had been withheld for 2 days. Scale indicates temperature (°C).

Mentions: A γ- irradiation induced mutant population had been derived from seeds of the ABA deficient aba3-1 mutant. Seedlings from M2 pools were screened by infrared thermography for suppression of the cold leaf phenotype observed in the original aba3-1 mutant. Of 130 plants that exhibited a hot leaf phenotype in the primary screen, 17 showed a heritable phenotype in the M3 generation and were named hot ABA deficiency suppressor (has) aba3-1 (as shown in Figure 1A-1C for has1 aba3-1 to has3 aba3-1). The presence of the original aba3-1 mutation (G3707 to A) was confirmed in the mutants by sequencing of genomic DNA. In addition, the absence of a functional sulfurylated molybdenum cofactor was verified by the absence of xanthine dehydrogenase activity, another enzyme that requires the same cofactor as AAO3 (Figure S1). This indicated that the loci were all extragenic suppressors of the aba3-1 mutation.


New ABA-hypersensitive Arabidopsis mutants are affected in loci mediating responses to water deficit and Dickeya dadantii infection.

Plessis A, Cournol R, Effroy D, Silva Pérez V, Botran L, Kraepiel Y, Frey A, Sotta B, Cornic G, Leung J, Giraudat J, Marion-Poll A, North HM - PLoS ONE (2011)

Hot leaf phenotype of has aba3-1 and has mutants visualised by thermal imaging.False colour infrared image of the temperature of drought stressed plants. (A–C) leaf temperature of has aba3-1 mutants compared to wild-type (WT) and the aba3-1 mutant. (D–F) leaf temperature of has mutants compared to wild-type. Plants were 14 days old and watering had been withheld for 2 days. Scale indicates temperature (°C).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3102102&req=5

pone-0020243-g001: Hot leaf phenotype of has aba3-1 and has mutants visualised by thermal imaging.False colour infrared image of the temperature of drought stressed plants. (A–C) leaf temperature of has aba3-1 mutants compared to wild-type (WT) and the aba3-1 mutant. (D–F) leaf temperature of has mutants compared to wild-type. Plants were 14 days old and watering had been withheld for 2 days. Scale indicates temperature (°C).
Mentions: A γ- irradiation induced mutant population had been derived from seeds of the ABA deficient aba3-1 mutant. Seedlings from M2 pools were screened by infrared thermography for suppression of the cold leaf phenotype observed in the original aba3-1 mutant. Of 130 plants that exhibited a hot leaf phenotype in the primary screen, 17 showed a heritable phenotype in the M3 generation and were named hot ABA deficiency suppressor (has) aba3-1 (as shown in Figure 1A-1C for has1 aba3-1 to has3 aba3-1). The presence of the original aba3-1 mutation (G3707 to A) was confirmed in the mutants by sequencing of genomic DNA. In addition, the absence of a functional sulfurylated molybdenum cofactor was verified by the absence of xanthine dehydrogenase activity, another enzyme that requires the same cofactor as AAO3 (Figure S1). This indicated that the loci were all extragenic suppressors of the aba3-1 mutation.

Bottom Line: The has2 mutant also exhibited increased germination inhibition by ABA, while ABA-inducible gene expression was not modified on dehydration, indicating the mutated gene affects early ABA-signalling responses that do not modify transcript levels.In contrast, weak ABA-hypersensitivity relative to mutant developmental phenotypes suggests that HAS3 regulates drought responses by both ABA-dependent and independent pathways. has1 mutant phenotypes were only apparent on stress or ABA treatments, and included reduced water loss on rapid dehydration.In contrast to has2, has1 exhibited only minor changes in susceptibility to Dickeya dadantii despite similar ABA-hypersensitivity, indicating that crosstalk between ABA responses to this pathogen and drought stress can occur through more than one point in the signalling pathway.

View Article: PubMed Central - PubMed

Affiliation: Institut Jean-Pierre Bourgin, UMR1318, INRA, AgroParisTech, Versailles, France.

ABSTRACT
On water deficit, abscisic acid (ABA) induces stomata closure to reduce water loss by transpiration. To identify Arabidopsis thaliana mutants which transpire less on drought, infrared thermal imaging of leaf temperature has been used to screen for suppressors of an ABA-deficient mutant (aba3-1) cold-leaf phenotype. Three novel mutants, called hot ABA-deficiency suppressor (has), have been identified with hot-leaf phenotypes in the absence of the aba3 mutation. The defective genes imparted no apparent modification to ABA production on water deficit, were inherited recessively and enhanced ABA responses indicating that the proteins encoded are negative regulators of ABA signalling. All three mutants showed ABA-hypersensitive stomata closure and inhibition of root elongation with little modification of growth and development in non-stressed conditions. The has2 mutant also exhibited increased germination inhibition by ABA, while ABA-inducible gene expression was not modified on dehydration, indicating the mutated gene affects early ABA-signalling responses that do not modify transcript levels. In contrast, weak ABA-hypersensitivity relative to mutant developmental phenotypes suggests that HAS3 regulates drought responses by both ABA-dependent and independent pathways. has1 mutant phenotypes were only apparent on stress or ABA treatments, and included reduced water loss on rapid dehydration. The HAS1 locus thus has the required characteristics for a targeted approach to improving resistance to water deficit. In contrast to has2, has1 exhibited only minor changes in susceptibility to Dickeya dadantii despite similar ABA-hypersensitivity, indicating that crosstalk between ABA responses to this pathogen and drought stress can occur through more than one point in the signalling pathway.

Show MeSH
Related in: MedlinePlus