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Camalexin contributes to the partial resistance of Arabidopsis thaliana to the biotrophic soilborne protist Plasmodiophora brassicae.

Lemarié S, Robert-Seilaniantz A, Lariagon C, Lemoine J, Marnet N, Levrel A, Jubault M, Manzanares-Dauleux MJ, Gravot A - Front Plant Sci (2015)

Bottom Line: This induction correlated with slower P. brassicae growth in Bur-0 compared to Col-0, thus suggesting a relationship between the levels of camalexin biosynthesis and the different levels of resistance.The Bur/Col allelic substitution in the region of the previously identified clubroot resistance QTL PbAt5.2 (Chromosome 5) was associated with both the enhanced clubroot-triggered induction of camalexin biosynthesis and the reduced P. brassicae development.Altogether, our results suggest that high levels of clubroot-triggered camalexin biosynthesis play a role in the quantitative control of partial resistance of Arabidopsis to clubroot.

View Article: PubMed Central - PubMed

Affiliation: UMR1349 IGEPP, INRA Le Rheu, France.

ABSTRACT
Camalexin has been reported to play defensive functions against several pathogens in Arabidopsis. In this study, we investigated the possible role of camalexin accumulation in two Arabidopsis genotypes with different levels of basal resistance to the compatible eH strain of the clubroot agent Plasmodiophora brassicae. Camalexin biosynthesis was induced in infected roots of both Col-0 (susceptible) and Bur-0 (partially resistant) accessions during the secondary phase of infection. However, the level of accumulation was four-to-seven times higher in Bur-0 than Col-0. This was associated with the enhanced transcription of a set of camalexin biosynthetic P450 genes in Bur-0: CYP71A13, CYP71A12, and CYP79B2. This induction correlated with slower P. brassicae growth in Bur-0 compared to Col-0, thus suggesting a relationship between the levels of camalexin biosynthesis and the different levels of resistance. Clubroot-triggered biosynthesis of camalexin may also participate in basal defense in Col-0, as gall symptoms and pathogen development were enhanced in the pad3 mutant (Col-0 genetic background), which is defective in camalexin biosynthesis. Clubroot and camalexin responses were then studied in Heterogeneous Inbred Families (HIF) lines derived from a cross between Bur-0 and Col-0. The Bur/Col allelic substitution in the region of the previously identified clubroot resistance QTL PbAt5.2 (Chromosome 5) was associated with both the enhanced clubroot-triggered induction of camalexin biosynthesis and the reduced P. brassicae development. Altogether, our results suggest that high levels of clubroot-triggered camalexin biosynthesis play a role in the quantitative control of partial resistance of Arabidopsis to clubroot.

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(A,B) Camalexin content in infected (continuous lines) and non-infected (dashed lines) roots of the HIFs 499 (A) and 508 (B) at 10, 14, and 17 dpi. 499-Bur and 499-Col harbor the Bur-0 and Col-0 alleles, respectively, at the QTL PbAt5.2. 508-Bur and 508-Col harbor the Bur-0 and Col-0 alleles, respectively, at the QTL PbAt1. (A,B), Camalexin was quantified in root methanol extracts using UPLC-MS/MS, and is expressed as ng g−1 of the fresh weight. Error bars represents standard error (Three biological replicates, 12–54 plants per biological replicate). Asterisks represent statistically significant differences according to the Wald tests applied on a linear mixed model (P < 0.05).
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Figure 8: (A,B) Camalexin content in infected (continuous lines) and non-infected (dashed lines) roots of the HIFs 499 (A) and 508 (B) at 10, 14, and 17 dpi. 499-Bur and 499-Col harbor the Bur-0 and Col-0 alleles, respectively, at the QTL PbAt5.2. 508-Bur and 508-Col harbor the Bur-0 and Col-0 alleles, respectively, at the QTL PbAt1. (A,B), Camalexin was quantified in root methanol extracts using UPLC-MS/MS, and is expressed as ng g−1 of the fresh weight. Error bars represents standard error (Three biological replicates, 12–54 plants per biological replicate). Asterisks represent statistically significant differences according to the Wald tests applied on a linear mixed model (P < 0.05).

Mentions: The camalexin content was then analyzed in inoculated and non-inoculated roots of the HIF 499 and HIF 508 pairs at 10, 14, and 17 dpi (Figure 8). During clubroot infection, camalexin levels increased significantly in both HIF pairs. Comparison of camalexin accumulation in infected HIF 499-Bur and 499-Col lines revealed that the Bur-allele at the PbAt5.2 region leads to a significant enhancement in the amount of camalexin (Figure 8A). In contrast, analysis of the 508 HIF lines revealed that allelic variation in the PbAt1 region did not affect the camalexin levels in response to clubroot (Figure 8B).


Camalexin contributes to the partial resistance of Arabidopsis thaliana to the biotrophic soilborne protist Plasmodiophora brassicae.

Lemarié S, Robert-Seilaniantz A, Lariagon C, Lemoine J, Marnet N, Levrel A, Jubault M, Manzanares-Dauleux MJ, Gravot A - Front Plant Sci (2015)

(A,B) Camalexin content in infected (continuous lines) and non-infected (dashed lines) roots of the HIFs 499 (A) and 508 (B) at 10, 14, and 17 dpi. 499-Bur and 499-Col harbor the Bur-0 and Col-0 alleles, respectively, at the QTL PbAt5.2. 508-Bur and 508-Col harbor the Bur-0 and Col-0 alleles, respectively, at the QTL PbAt1. (A,B), Camalexin was quantified in root methanol extracts using UPLC-MS/MS, and is expressed as ng g−1 of the fresh weight. Error bars represents standard error (Three biological replicates, 12–54 plants per biological replicate). Asterisks represent statistically significant differences according to the Wald tests applied on a linear mixed model (P < 0.05).
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Related In: Results  -  Collection

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Figure 8: (A,B) Camalexin content in infected (continuous lines) and non-infected (dashed lines) roots of the HIFs 499 (A) and 508 (B) at 10, 14, and 17 dpi. 499-Bur and 499-Col harbor the Bur-0 and Col-0 alleles, respectively, at the QTL PbAt5.2. 508-Bur and 508-Col harbor the Bur-0 and Col-0 alleles, respectively, at the QTL PbAt1. (A,B), Camalexin was quantified in root methanol extracts using UPLC-MS/MS, and is expressed as ng g−1 of the fresh weight. Error bars represents standard error (Three biological replicates, 12–54 plants per biological replicate). Asterisks represent statistically significant differences according to the Wald tests applied on a linear mixed model (P < 0.05).
Mentions: The camalexin content was then analyzed in inoculated and non-inoculated roots of the HIF 499 and HIF 508 pairs at 10, 14, and 17 dpi (Figure 8). During clubroot infection, camalexin levels increased significantly in both HIF pairs. Comparison of camalexin accumulation in infected HIF 499-Bur and 499-Col lines revealed that the Bur-allele at the PbAt5.2 region leads to a significant enhancement in the amount of camalexin (Figure 8A). In contrast, analysis of the 508 HIF lines revealed that allelic variation in the PbAt1 region did not affect the camalexin levels in response to clubroot (Figure 8B).

Bottom Line: This induction correlated with slower P. brassicae growth in Bur-0 compared to Col-0, thus suggesting a relationship between the levels of camalexin biosynthesis and the different levels of resistance.The Bur/Col allelic substitution in the region of the previously identified clubroot resistance QTL PbAt5.2 (Chromosome 5) was associated with both the enhanced clubroot-triggered induction of camalexin biosynthesis and the reduced P. brassicae development.Altogether, our results suggest that high levels of clubroot-triggered camalexin biosynthesis play a role in the quantitative control of partial resistance of Arabidopsis to clubroot.

View Article: PubMed Central - PubMed

Affiliation: UMR1349 IGEPP, INRA Le Rheu, France.

ABSTRACT
Camalexin has been reported to play defensive functions against several pathogens in Arabidopsis. In this study, we investigated the possible role of camalexin accumulation in two Arabidopsis genotypes with different levels of basal resistance to the compatible eH strain of the clubroot agent Plasmodiophora brassicae. Camalexin biosynthesis was induced in infected roots of both Col-0 (susceptible) and Bur-0 (partially resistant) accessions during the secondary phase of infection. However, the level of accumulation was four-to-seven times higher in Bur-0 than Col-0. This was associated with the enhanced transcription of a set of camalexin biosynthetic P450 genes in Bur-0: CYP71A13, CYP71A12, and CYP79B2. This induction correlated with slower P. brassicae growth in Bur-0 compared to Col-0, thus suggesting a relationship between the levels of camalexin biosynthesis and the different levels of resistance. Clubroot-triggered biosynthesis of camalexin may also participate in basal defense in Col-0, as gall symptoms and pathogen development were enhanced in the pad3 mutant (Col-0 genetic background), which is defective in camalexin biosynthesis. Clubroot and camalexin responses were then studied in Heterogeneous Inbred Families (HIF) lines derived from a cross between Bur-0 and Col-0. The Bur/Col allelic substitution in the region of the previously identified clubroot resistance QTL PbAt5.2 (Chromosome 5) was associated with both the enhanced clubroot-triggered induction of camalexin biosynthesis and the reduced P. brassicae development. Altogether, our results suggest that high levels of clubroot-triggered camalexin biosynthesis play a role in the quantitative control of partial resistance of Arabidopsis to clubroot.

No MeSH data available.


Related in: MedlinePlus