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The Hv-SGT1 gene from Haynaldia villosa contributes to resistances towards both biotrophic and hemi-biotrophic pathogens in common wheat (Triticum aestivum L.).

Xing L, Qian C, Cao A, Li Y, Jiang Z, Li M, Jin X, Hu J, Zhang Y, Wang X, Chen P - PLoS ONE (2013)

Bottom Line: The demonstration that silencing of Hv-SGT1 substantially reduced resistance to Bgt indicated that Hv-SGT1 was an essential component of disease resistance in H. villosa.Therefore, the involvement of Hv-SGT1 in H2O2 production correlates with the hypersensitive response and jasmonic acid signaling.Our novel demonstration that wheat with over-expressed Hv-SGT1 showed enhanced resistance to both powdery mildew and FHB suggests that it could served as a transgenic genetic resource in wheat breeding for multiple disease resistance.

View Article: PubMed Central - PubMed

Affiliation: The National Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China.

ABSTRACT
The SGT1 protein is essential for R protein-mediated and PAMPs-triggered resistance in many plant species. Here we reported the isolation and characterization of the Hv-SGT1 gene from Haynaldiavillosa (2n = 14, VV). Analysis of the subcellular location of Hv-SGT1 by transient expression of a fusion to GFP indicated its presence in the cytoplasm and nucleus. Levels of Hv-SGT1 transcripts were increased by inoculation with either the biotrophic pathogen Blumeriagraminis DC. f. Sp. tritici (Bgt) or the hemi-biotrophic pathogen Fusariumgraminearum (Fg). Levels of Hv-SGT1 showed substantial increase following treatment with H2O2 and methyl jasmonate (MeJA), only slightly induced following exposure to ethephon or abscisic acid, but not changed following exposure to salicylic acid. The demonstration that silencing of Hv-SGT1 substantially reduced resistance to Bgt indicated that Hv-SGT1 was an essential component of disease resistance in H. villosa. The over-expression of Hv-SGT1 in Yangmai 158 enhanced resistance to powdery mildew, and this correlated with increased levels of whole-cell reactive oxygen intermediates at the sites of penetration by the pathogens. Compared with wild-type plants, the expression levels of genes related to the H2O2 and JA signaling pathways were lower in the Hv-SGT1 silenced plants and higher in the Hv-SGT1 over-expressing plants. Therefore, the involvement of Hv-SGT1 in H2O2 production correlates with the hypersensitive response and jasmonic acid signaling. Our novel demonstration that wheat with over-expressed Hv-SGT1 showed enhanced resistance to both powdery mildew and FHB suggests that it could served as a transgenic genetic resource in wheat breeding for multiple disease resistance.

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Hydrogen peroxide accumulation in leaves of Hv-SGT1 over-expressing plants and the WT Yangmai 158.Hydrogen peroxide accumulated in Yangmai 158 (A), and Hv-SGT1 over-expressing lines OX-323 (B) and OX-330 (C). (D) Whole-cell ROI accumulation. (E) Oxidative burst at the Bgt interaction site. (F) Comparison of the percentage of cells with H2O2 accumulation throughout the entire cell or only around the infection sites in wild-type Yangmai 158 and the transgenic plants (* means p < 0.05).
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pone-0072571-g007: Hydrogen peroxide accumulation in leaves of Hv-SGT1 over-expressing plants and the WT Yangmai 158.Hydrogen peroxide accumulated in Yangmai 158 (A), and Hv-SGT1 over-expressing lines OX-323 (B) and OX-330 (C). (D) Whole-cell ROI accumulation. (E) Oxidative burst at the Bgt interaction site. (F) Comparison of the percentage of cells with H2O2 accumulation throughout the entire cell or only around the infection sites in wild-type Yangmai 158 and the transgenic plants (* means p < 0.05).

Mentions: Histological examination revealed that lines that over-expressed Hv-SGT1 showed a higher frequency of Bgt-induced whole-cell oxidative burst. Staining with 3, 3′-diaminobenzidine (DAB), which allows detection of H2O2, did not uncover genotype-specific differences at an early stage of the interaction (12 h post inoculation [hpi], data not shown). At 24 hpi, the fungus had penetrated epidermal host cells in up to 60% of interaction sites in wild-type (WT) plants as well as in the transgenic lines OX-323 and OX-330. Detection of DAB polymerization showed a similar whole-cell accumulation ratio of H2O2 in both OX-323 and OX-330 (Figure 7A and 7B). In contrast, only a few DAB-stained cells (Figure 7D) was detected in WT Yangmai 158, although appressorial germ tube (AGT) penetration sites and primary germ tube (PGT) penetration sites with oxidative burst points were observed (Figure 7C). More ROIs accumulated in most pathogen-inoculated transgenic leaves (11.4% in OX-323, 9.7% in OX-330) than in the inoculated Yangmai 158 leaves (4.2%), although there was no significant difference in the frequencies with which oxidative burst points formed at Bgt interaction sites (Figure 7E) in leaves from WT, OX-323, or OX-330 plants (Figure 7F). These revealed that the pathways responsible for the oxidative burst were activated for the host defense response though regulation of Hv-SGT1.


The Hv-SGT1 gene from Haynaldia villosa contributes to resistances towards both biotrophic and hemi-biotrophic pathogens in common wheat (Triticum aestivum L.).

Xing L, Qian C, Cao A, Li Y, Jiang Z, Li M, Jin X, Hu J, Zhang Y, Wang X, Chen P - PLoS ONE (2013)

Hydrogen peroxide accumulation in leaves of Hv-SGT1 over-expressing plants and the WT Yangmai 158.Hydrogen peroxide accumulated in Yangmai 158 (A), and Hv-SGT1 over-expressing lines OX-323 (B) and OX-330 (C). (D) Whole-cell ROI accumulation. (E) Oxidative burst at the Bgt interaction site. (F) Comparison of the percentage of cells with H2O2 accumulation throughout the entire cell or only around the infection sites in wild-type Yangmai 158 and the transgenic plants (* means p < 0.05).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3760960&req=5

pone-0072571-g007: Hydrogen peroxide accumulation in leaves of Hv-SGT1 over-expressing plants and the WT Yangmai 158.Hydrogen peroxide accumulated in Yangmai 158 (A), and Hv-SGT1 over-expressing lines OX-323 (B) and OX-330 (C). (D) Whole-cell ROI accumulation. (E) Oxidative burst at the Bgt interaction site. (F) Comparison of the percentage of cells with H2O2 accumulation throughout the entire cell or only around the infection sites in wild-type Yangmai 158 and the transgenic plants (* means p < 0.05).
Mentions: Histological examination revealed that lines that over-expressed Hv-SGT1 showed a higher frequency of Bgt-induced whole-cell oxidative burst. Staining with 3, 3′-diaminobenzidine (DAB), which allows detection of H2O2, did not uncover genotype-specific differences at an early stage of the interaction (12 h post inoculation [hpi], data not shown). At 24 hpi, the fungus had penetrated epidermal host cells in up to 60% of interaction sites in wild-type (WT) plants as well as in the transgenic lines OX-323 and OX-330. Detection of DAB polymerization showed a similar whole-cell accumulation ratio of H2O2 in both OX-323 and OX-330 (Figure 7A and 7B). In contrast, only a few DAB-stained cells (Figure 7D) was detected in WT Yangmai 158, although appressorial germ tube (AGT) penetration sites and primary germ tube (PGT) penetration sites with oxidative burst points were observed (Figure 7C). More ROIs accumulated in most pathogen-inoculated transgenic leaves (11.4% in OX-323, 9.7% in OX-330) than in the inoculated Yangmai 158 leaves (4.2%), although there was no significant difference in the frequencies with which oxidative burst points formed at Bgt interaction sites (Figure 7E) in leaves from WT, OX-323, or OX-330 plants (Figure 7F). These revealed that the pathways responsible for the oxidative burst were activated for the host defense response though regulation of Hv-SGT1.

Bottom Line: The demonstration that silencing of Hv-SGT1 substantially reduced resistance to Bgt indicated that Hv-SGT1 was an essential component of disease resistance in H. villosa.Therefore, the involvement of Hv-SGT1 in H2O2 production correlates with the hypersensitive response and jasmonic acid signaling.Our novel demonstration that wheat with over-expressed Hv-SGT1 showed enhanced resistance to both powdery mildew and FHB suggests that it could served as a transgenic genetic resource in wheat breeding for multiple disease resistance.

View Article: PubMed Central - PubMed

Affiliation: The National Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China.

ABSTRACT
The SGT1 protein is essential for R protein-mediated and PAMPs-triggered resistance in many plant species. Here we reported the isolation and characterization of the Hv-SGT1 gene from Haynaldiavillosa (2n = 14, VV). Analysis of the subcellular location of Hv-SGT1 by transient expression of a fusion to GFP indicated its presence in the cytoplasm and nucleus. Levels of Hv-SGT1 transcripts were increased by inoculation with either the biotrophic pathogen Blumeriagraminis DC. f. Sp. tritici (Bgt) or the hemi-biotrophic pathogen Fusariumgraminearum (Fg). Levels of Hv-SGT1 showed substantial increase following treatment with H2O2 and methyl jasmonate (MeJA), only slightly induced following exposure to ethephon or abscisic acid, but not changed following exposure to salicylic acid. The demonstration that silencing of Hv-SGT1 substantially reduced resistance to Bgt indicated that Hv-SGT1 was an essential component of disease resistance in H. villosa. The over-expression of Hv-SGT1 in Yangmai 158 enhanced resistance to powdery mildew, and this correlated with increased levels of whole-cell reactive oxygen intermediates at the sites of penetration by the pathogens. Compared with wild-type plants, the expression levels of genes related to the H2O2 and JA signaling pathways were lower in the Hv-SGT1 silenced plants and higher in the Hv-SGT1 over-expressing plants. Therefore, the involvement of Hv-SGT1 in H2O2 production correlates with the hypersensitive response and jasmonic acid signaling. Our novel demonstration that wheat with over-expressed Hv-SGT1 showed enhanced resistance to both powdery mildew and FHB suggests that it could served as a transgenic genetic resource in wheat breeding for multiple disease resistance.

Show MeSH
Related in: MedlinePlus