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TaHsfA6f is a transcriptional activator that regulates a suite of heat stress protection genes in wheat (Triticum aestivum L.) including previously unknown Hsf targets.

Xue GP, Drenth J, McIntyre CL - J. Exp. Bot. (2014)

Bottom Line: Transgenic wheat plants overexpressing TaHsfA6f showed improved thermotolerance.Promoter truncation and mutagenesis analyses identified TaHsfA6f-binding elements that were responsible for transactivation of TaHSP90.1-A1 and TaGAAP by TaHsfA6f.These data suggest that TaHsfA6f is a transcriptional activator that directly regulates TaHSP, TaGAAP, and TaRof1 genes in wheat and its gene regulatory network has a positive impact on thermotolerance.

View Article: PubMed Central - PubMed

Affiliation: CSIRO Plant Industry, 306 Carmody Road, St Lucia, Qld 4067, Australia gang-ping.xue@csiro.au.

No MeSH data available.


Related in: MedlinePlus

Transactivation analysis of GFP reporter genes driven by the promoters of TaHsfA6f target genes in wheat seedlings. (A) Reporter and effector constructs. (B) Transactivation analysis. GFP foci (green) indicate GFP reporter gene expression. Blue foci resulted from the expression of a co-introduced Ubi1:GUS+ reporter and indicate that tissue sections were transformed with these constructs. The red background is the fluorescence from shoot chlorophyll. The GFP expression of all these reporter constructs was induced at 36 °C, including those driven by TaHSP promoters (Supplementary Fig. S2). The TaHsfA6f effector construct activated the expression of reporter genes driven by TaGAAP, TaRof1, and TaHSP promoters, but not TaRCA-L promoter at 22 °C. Illustration of GUS foci is given only when GFP reporter expression is essentially undetectable in the tissue section.
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Figure 4: Transactivation analysis of GFP reporter genes driven by the promoters of TaHsfA6f target genes in wheat seedlings. (A) Reporter and effector constructs. (B) Transactivation analysis. GFP foci (green) indicate GFP reporter gene expression. Blue foci resulted from the expression of a co-introduced Ubi1:GUS+ reporter and indicate that tissue sections were transformed with these constructs. The red background is the fluorescence from shoot chlorophyll. The GFP expression of all these reporter constructs was induced at 36 °C, including those driven by TaHSP promoters (Supplementary Fig. S2). The TaHsfA6f effector construct activated the expression of reporter genes driven by TaGAAP, TaRof1, and TaHSP promoters, but not TaRCA-L promoter at 22 °C. Illustration of GUS foci is given only when GFP reporter expression is essentially undetectable in the tissue section.

Mentions: To identify target genes directly regulated by TaHsfA6f, the promoter sequences of seven genes up-regulated by TaHsfA6f were successfully identified through sequence assembly from a partial wheat genome sequence database in CerealDB (Wilkinson et al., 2012) and were subsequently isolated. The isolated promoters were used to drive the expression of the green fluorescence protein (GFP) reporter gene (Fig. 4A). The TaHsfA6f effector construct was driven by a constitutive maize Ubi1 promoter. Transactivation analysis was performed by bombarding reporter and effector constructs into wheat seedlings. As shown in Fig. 4B, the expression of the GFP reporter gene driven by the promoter of TaGAAP or TaRof1 was induced by heat stress or by co-introduction with the TaHsfA6f effector construct without a heat treatment. In contrast, TaRCA-L promoter-driven reporter was inducible by heat, but not by TaHsfA6f. The GFP reporter driven by a HSP promoter (TaHSP16.8, TaHSP17, TaHSP17.3, or TaHSP90.1-A1) was also strongly induced by heat treatment at 36 °C (Supplementary Fig. S4) or by TaHsfA6f (Fig. 4B). These data indicate that all of the analysed genes except TaRCA-L are potentially direct targets of TaHsfA6f.


TaHsfA6f is a transcriptional activator that regulates a suite of heat stress protection genes in wheat (Triticum aestivum L.) including previously unknown Hsf targets.

Xue GP, Drenth J, McIntyre CL - J. Exp. Bot. (2014)

Transactivation analysis of GFP reporter genes driven by the promoters of TaHsfA6f target genes in wheat seedlings. (A) Reporter and effector constructs. (B) Transactivation analysis. GFP foci (green) indicate GFP reporter gene expression. Blue foci resulted from the expression of a co-introduced Ubi1:GUS+ reporter and indicate that tissue sections were transformed with these constructs. The red background is the fluorescence from shoot chlorophyll. The GFP expression of all these reporter constructs was induced at 36 °C, including those driven by TaHSP promoters (Supplementary Fig. S2). The TaHsfA6f effector construct activated the expression of reporter genes driven by TaGAAP, TaRof1, and TaHSP promoters, but not TaRCA-L promoter at 22 °C. Illustration of GUS foci is given only when GFP reporter expression is essentially undetectable in the tissue section.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
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Figure 4: Transactivation analysis of GFP reporter genes driven by the promoters of TaHsfA6f target genes in wheat seedlings. (A) Reporter and effector constructs. (B) Transactivation analysis. GFP foci (green) indicate GFP reporter gene expression. Blue foci resulted from the expression of a co-introduced Ubi1:GUS+ reporter and indicate that tissue sections were transformed with these constructs. The red background is the fluorescence from shoot chlorophyll. The GFP expression of all these reporter constructs was induced at 36 °C, including those driven by TaHSP promoters (Supplementary Fig. S2). The TaHsfA6f effector construct activated the expression of reporter genes driven by TaGAAP, TaRof1, and TaHSP promoters, but not TaRCA-L promoter at 22 °C. Illustration of GUS foci is given only when GFP reporter expression is essentially undetectable in the tissue section.
Mentions: To identify target genes directly regulated by TaHsfA6f, the promoter sequences of seven genes up-regulated by TaHsfA6f were successfully identified through sequence assembly from a partial wheat genome sequence database in CerealDB (Wilkinson et al., 2012) and were subsequently isolated. The isolated promoters were used to drive the expression of the green fluorescence protein (GFP) reporter gene (Fig. 4A). The TaHsfA6f effector construct was driven by a constitutive maize Ubi1 promoter. Transactivation analysis was performed by bombarding reporter and effector constructs into wheat seedlings. As shown in Fig. 4B, the expression of the GFP reporter gene driven by the promoter of TaGAAP or TaRof1 was induced by heat stress or by co-introduction with the TaHsfA6f effector construct without a heat treatment. In contrast, TaRCA-L promoter-driven reporter was inducible by heat, but not by TaHsfA6f. The GFP reporter driven by a HSP promoter (TaHSP16.8, TaHSP17, TaHSP17.3, or TaHSP90.1-A1) was also strongly induced by heat treatment at 36 °C (Supplementary Fig. S4) or by TaHsfA6f (Fig. 4B). These data indicate that all of the analysed genes except TaRCA-L are potentially direct targets of TaHsfA6f.

Bottom Line: Transgenic wheat plants overexpressing TaHsfA6f showed improved thermotolerance.Promoter truncation and mutagenesis analyses identified TaHsfA6f-binding elements that were responsible for transactivation of TaHSP90.1-A1 and TaGAAP by TaHsfA6f.These data suggest that TaHsfA6f is a transcriptional activator that directly regulates TaHSP, TaGAAP, and TaRof1 genes in wheat and its gene regulatory network has a positive impact on thermotolerance.

View Article: PubMed Central - PubMed

Affiliation: CSIRO Plant Industry, 306 Carmody Road, St Lucia, Qld 4067, Australia gang-ping.xue@csiro.au.

No MeSH data available.


Related in: MedlinePlus