Limits...
The maize OST1 kinase homolog phosphorylates and regulates the maize SNAC1-type transcription factor.

Vilela B, Moreno-Cortés A, Rabissi A, Leung J, Pagès M, Lumbreras V - PLoS ONE (2013)

Bottom Line: Furthermore, we have identified the transcription factor, ZmSNAC1, which is directly phosphorylated by ZmOST1 with implications on its localization and protein stability.Interestingly, ZmSNAC1 binds to the ABA-box of ZmOST1, which is conserved in SnRK2s activated by ABA and is part of the contact site for the negative-regulating clade A PP2C phosphatases.Taken together, our results indicate that ZmSNAC1 is a substrate of ZmOST1 and delineate a novel osmotic stress transcriptional pathway in maize.

View Article: PubMed Central - PubMed

Affiliation: Centre for Research in Agricultural Genomics, Bellaterra, Cerdanyola del Vallés, Spain.

ABSTRACT
The Arabidopsis kinase OPEN STOMATA 1 (OST1) plays a key role in regulating drought stress signalling, particularly stomatal closure. We have identified and investigated the functions of the OST1 ortholog in Z. mays (ZmOST1). Ectopic expression of ZmOST1 in the Arabidopsis ost1 mutant restores the stomatal closure phenotype in response to drought. Furthermore, we have identified the transcription factor, ZmSNAC1, which is directly phosphorylated by ZmOST1 with implications on its localization and protein stability. Interestingly, ZmSNAC1 binds to the ABA-box of ZmOST1, which is conserved in SnRK2s activated by ABA and is part of the contact site for the negative-regulating clade A PP2C phosphatases. Taken together, our results indicate that ZmSNAC1 is a substrate of ZmOST1 and delineate a novel osmotic stress transcriptional pathway in maize.

Show MeSH

Related in: MedlinePlus

ZmOST1 interacts with ZmSNAC1.(A) Sequence alignment of maize and rice ZmSNAC1 proteins. The NAC-binding DNA domain is underlined below the alignment. (B) ZmOST1/ZmSNAC1 yeast two-hybrid interaction by growth in selective medium (left). β-galactosidase activity quantification of the co-transformed yeasts (right). Values are means ± SD of three independent experiments. 1, pGBT7-ZmOST1/pGAD424-ZmSNAC1 interaction; 2, α and β CK2 subunits interaction used as positive control; 3, pGBT7-ZmOST1/pGAD424 interaction as a negative control. (C) ZmOST1/ZmSNAC1 interaction is confirmed by in vitro pull-down assay. Equal amounts of labelled ZmSNAC1 were incubated with GST and GST-ZmOST1 proteins coupled to gluthathione-sepharose resin obtaining ZmSNAC1 specific in vitro retention.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3585266&req=5

pone-0058105-g002: ZmOST1 interacts with ZmSNAC1.(A) Sequence alignment of maize and rice ZmSNAC1 proteins. The NAC-binding DNA domain is underlined below the alignment. (B) ZmOST1/ZmSNAC1 yeast two-hybrid interaction by growth in selective medium (left). β-galactosidase activity quantification of the co-transformed yeasts (right). Values are means ± SD of three independent experiments. 1, pGBT7-ZmOST1/pGAD424-ZmSNAC1 interaction; 2, α and β CK2 subunits interaction used as positive control; 3, pGBT7-ZmOST1/pGAD424 interaction as a negative control. (C) ZmOST1/ZmSNAC1 interaction is confirmed by in vitro pull-down assay. Equal amounts of labelled ZmSNAC1 were incubated with GST and GST-ZmOST1 proteins coupled to gluthathione-sepharose resin obtaining ZmSNAC1 specific in vitro retention.

Mentions: To identify unknown ZmOST1 targets, we performed a yeast two-hybrid screen using ZmOST1 as the bait, and as prey, a cDNA library from maize leaves dehydrated for 3 hours. Among several positives clones, we focused on a SNAC1-related transcription factor for further characterization. The ZmSNAC1 clone encodes a protein of 312 amino acids highly homologous to rice SNAC1 (Figure 2A) which functions mainly in stomatal regulation [35]. Both proteins are almost identical in their DNA-binding NAC domains suggesting that they are functionally conserved.


The maize OST1 kinase homolog phosphorylates and regulates the maize SNAC1-type transcription factor.

Vilela B, Moreno-Cortés A, Rabissi A, Leung J, Pagès M, Lumbreras V - PLoS ONE (2013)

ZmOST1 interacts with ZmSNAC1.(A) Sequence alignment of maize and rice ZmSNAC1 proteins. The NAC-binding DNA domain is underlined below the alignment. (B) ZmOST1/ZmSNAC1 yeast two-hybrid interaction by growth in selective medium (left). β-galactosidase activity quantification of the co-transformed yeasts (right). Values are means ± SD of three independent experiments. 1, pGBT7-ZmOST1/pGAD424-ZmSNAC1 interaction; 2, α and β CK2 subunits interaction used as positive control; 3, pGBT7-ZmOST1/pGAD424 interaction as a negative control. (C) ZmOST1/ZmSNAC1 interaction is confirmed by in vitro pull-down assay. Equal amounts of labelled ZmSNAC1 were incubated with GST and GST-ZmOST1 proteins coupled to gluthathione-sepharose resin obtaining ZmSNAC1 specific in vitro retention.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3585266&req=5

pone-0058105-g002: ZmOST1 interacts with ZmSNAC1.(A) Sequence alignment of maize and rice ZmSNAC1 proteins. The NAC-binding DNA domain is underlined below the alignment. (B) ZmOST1/ZmSNAC1 yeast two-hybrid interaction by growth in selective medium (left). β-galactosidase activity quantification of the co-transformed yeasts (right). Values are means ± SD of three independent experiments. 1, pGBT7-ZmOST1/pGAD424-ZmSNAC1 interaction; 2, α and β CK2 subunits interaction used as positive control; 3, pGBT7-ZmOST1/pGAD424 interaction as a negative control. (C) ZmOST1/ZmSNAC1 interaction is confirmed by in vitro pull-down assay. Equal amounts of labelled ZmSNAC1 were incubated with GST and GST-ZmOST1 proteins coupled to gluthathione-sepharose resin obtaining ZmSNAC1 specific in vitro retention.
Mentions: To identify unknown ZmOST1 targets, we performed a yeast two-hybrid screen using ZmOST1 as the bait, and as prey, a cDNA library from maize leaves dehydrated for 3 hours. Among several positives clones, we focused on a SNAC1-related transcription factor for further characterization. The ZmSNAC1 clone encodes a protein of 312 amino acids highly homologous to rice SNAC1 (Figure 2A) which functions mainly in stomatal regulation [35]. Both proteins are almost identical in their DNA-binding NAC domains suggesting that they are functionally conserved.

Bottom Line: Furthermore, we have identified the transcription factor, ZmSNAC1, which is directly phosphorylated by ZmOST1 with implications on its localization and protein stability.Interestingly, ZmSNAC1 binds to the ABA-box of ZmOST1, which is conserved in SnRK2s activated by ABA and is part of the contact site for the negative-regulating clade A PP2C phosphatases.Taken together, our results indicate that ZmSNAC1 is a substrate of ZmOST1 and delineate a novel osmotic stress transcriptional pathway in maize.

View Article: PubMed Central - PubMed

Affiliation: Centre for Research in Agricultural Genomics, Bellaterra, Cerdanyola del Vallés, Spain.

ABSTRACT
The Arabidopsis kinase OPEN STOMATA 1 (OST1) plays a key role in regulating drought stress signalling, particularly stomatal closure. We have identified and investigated the functions of the OST1 ortholog in Z. mays (ZmOST1). Ectopic expression of ZmOST1 in the Arabidopsis ost1 mutant restores the stomatal closure phenotype in response to drought. Furthermore, we have identified the transcription factor, ZmSNAC1, which is directly phosphorylated by ZmOST1 with implications on its localization and protein stability. Interestingly, ZmSNAC1 binds to the ABA-box of ZmOST1, which is conserved in SnRK2s activated by ABA and is part of the contact site for the negative-regulating clade A PP2C phosphatases. Taken together, our results indicate that ZmSNAC1 is a substrate of ZmOST1 and delineate a novel osmotic stress transcriptional pathway in maize.

Show MeSH
Related in: MedlinePlus