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Systemic responses in a tolerant olive (Olea europaea L.) cultivar upon root colonization by the vascular pathogen Verticillium dahliae.

Gómez-Lama Cabanás C, Schilirò E, Valverde-Corredor A, Mercado-Blanco J - Front Microbiol (2015)

Bottom Line: A total of 585 FU and 381 FD unigenes were identified, many of them involved in defense response to (a)biotic stresses.Selected genes were then used to validate libraries and evaluate their temporal expression pattern in "Frantoio." Four defense genes were analyzed in cultivars Changlot Real (tolerant) and Picual (susceptible).An association between GRAS1 and DRR2 gene expression patterns and susceptibility to VWO was observed, suggesting that these transcripts could be further evaluated as markers of the tolerance level of olive cultivars to V. dahliae.

View Article: PubMed Central - PubMed

Affiliation: Department of Crop Protection, Institute for Sustainable Agriculture, Consejo Superior de Investigaciones Científicas Córdoba, Spain.

ABSTRACT
Verticillium wilt of olive (VWO) is caused by the vascular pathogen Verticillium dahliae. One of the best VWO management measures is the use of tolerant cultivars; however, our knowledge on VWO tolerance/resistance genetics is very limited. A transcriptomic analysis was conducted to (i) identify systemic defense responses induced/repressed in aerial tissues of the tolerant cultivar Frantoio upon root colonization by V. dahliae, and (ii) determine the expression pattern of selected defense genes in olive cultivars showing differential susceptibility to VWO. Two suppression subtractive hybridization cDNA libraries, enriched in up-regulated (FU) and down-regulated (FD) genes respectively, were generated from "Frantoio" aerial tissues. Results showed that broad systemic transcriptomic changes are taking place during V. dahliae-"Frantoio" interaction. A total of 585 FU and 381 FD unigenes were identified, many of them involved in defense response to (a)biotic stresses. Selected genes were then used to validate libraries and evaluate their temporal expression pattern in "Frantoio." Four defense genes were analyzed in cultivars Changlot Real (tolerant) and Picual (susceptible). An association between GRAS1 and DRR2 gene expression patterns and susceptibility to VWO was observed, suggesting that these transcripts could be further evaluated as markers of the tolerance level of olive cultivars to V. dahliae.

No MeSH data available.


Related in: MedlinePlus

Relative expression (RE) average of seven genes identified in FD and/or FU cDNA libraries from aerial tissues of “Frantoio” olive plants at different time points after Verticillium dahliae inoculation in roots. ACO, 1-aminocyclopropane-1-carboxylate oxidase; DRR2, disease resistant response protein; ACL, acetone cyanohydrin lyase; GRAS1, transcription factor GRAS1; CO-MT, caffeoyl-o-methyltransferase; PR10, pathogenesis-related protein 10; and DEF, defensin protein 1. Error bars represent the SD from at least two independent qRT-PCR experiments. RE values (log2-fold-change values) were calculated according to the 2−ΔΔCt method (Livak and Schmittgen, 2001).
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Figure 2: Relative expression (RE) average of seven genes identified in FD and/or FU cDNA libraries from aerial tissues of “Frantoio” olive plants at different time points after Verticillium dahliae inoculation in roots. ACO, 1-aminocyclopropane-1-carboxylate oxidase; DRR2, disease resistant response protein; ACL, acetone cyanohydrin lyase; GRAS1, transcription factor GRAS1; CO-MT, caffeoyl-o-methyltransferase; PR10, pathogenesis-related protein 10; and DEF, defensin protein 1. Error bars represent the SD from at least two independent qRT-PCR experiments. RE values (log2-fold-change values) were calculated according to the 2−ΔΔCt method (Livak and Schmittgen, 2001).

Mentions: Seven genes identified in FU, FD or both libraries, CO-MT, GRAS1 (up-regulated genes), ACO, PR10, DEF, DRR2 (down-regulated genes), and ACL (found in both libraries) were selected to analyze short- and mid-term (8 h, 2, 4, 10, and 15 DAI) gene expression pattern. Overall, results showed a gene repression at 4DAI, followed by an increase at 10DAI. Most of the genes reached the maximal relative expression level within the first hours after pathogen inoculation (Figure 2). The two up-regulated genes identified in the FU library (CO-MT and GRAS1) were validated at all-time points except at 4DAI. Down regulation of two (ACO and DEF) out of four genes identified in the FD library was confirmed at three different times after pathogen inoculation. On the contrary, down-regulated expression of DRR2 and PR10 was validated only at two times (Figure 2). Finally, ACL gene, found in both libraries, displayed an ambiguous expression pattern along time. The vast majority of relative fold changes were assigned to medium (>+1.0 to ≤ +2.0 or < −1.0 to ≥ −2.0) or low (≥ −1.0 to ≤ +1.0 or ≤ 1.0 to ≥ −1.0) categories of differential expression, but for some cases such as DRR2 (8 h and 4DAI) and DEF (8 h and 10DAI), ACO and CO-MT (4DAI) or PR10 (4, 10, and 15DAI) which were assigned to the high category (>+2 or < −2) (Figure 2). Linear equations, correlation coefficients (R2) and PCR efficiencies for each gene are shown in Table 1.


Systemic responses in a tolerant olive (Olea europaea L.) cultivar upon root colonization by the vascular pathogen Verticillium dahliae.

Gómez-Lama Cabanás C, Schilirò E, Valverde-Corredor A, Mercado-Blanco J - Front Microbiol (2015)

Relative expression (RE) average of seven genes identified in FD and/or FU cDNA libraries from aerial tissues of “Frantoio” olive plants at different time points after Verticillium dahliae inoculation in roots. ACO, 1-aminocyclopropane-1-carboxylate oxidase; DRR2, disease resistant response protein; ACL, acetone cyanohydrin lyase; GRAS1, transcription factor GRAS1; CO-MT, caffeoyl-o-methyltransferase; PR10, pathogenesis-related protein 10; and DEF, defensin protein 1. Error bars represent the SD from at least two independent qRT-PCR experiments. RE values (log2-fold-change values) were calculated according to the 2−ΔΔCt method (Livak and Schmittgen, 2001).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4584997&req=5

Figure 2: Relative expression (RE) average of seven genes identified in FD and/or FU cDNA libraries from aerial tissues of “Frantoio” olive plants at different time points after Verticillium dahliae inoculation in roots. ACO, 1-aminocyclopropane-1-carboxylate oxidase; DRR2, disease resistant response protein; ACL, acetone cyanohydrin lyase; GRAS1, transcription factor GRAS1; CO-MT, caffeoyl-o-methyltransferase; PR10, pathogenesis-related protein 10; and DEF, defensin protein 1. Error bars represent the SD from at least two independent qRT-PCR experiments. RE values (log2-fold-change values) were calculated according to the 2−ΔΔCt method (Livak and Schmittgen, 2001).
Mentions: Seven genes identified in FU, FD or both libraries, CO-MT, GRAS1 (up-regulated genes), ACO, PR10, DEF, DRR2 (down-regulated genes), and ACL (found in both libraries) were selected to analyze short- and mid-term (8 h, 2, 4, 10, and 15 DAI) gene expression pattern. Overall, results showed a gene repression at 4DAI, followed by an increase at 10DAI. Most of the genes reached the maximal relative expression level within the first hours after pathogen inoculation (Figure 2). The two up-regulated genes identified in the FU library (CO-MT and GRAS1) were validated at all-time points except at 4DAI. Down regulation of two (ACO and DEF) out of four genes identified in the FD library was confirmed at three different times after pathogen inoculation. On the contrary, down-regulated expression of DRR2 and PR10 was validated only at two times (Figure 2). Finally, ACL gene, found in both libraries, displayed an ambiguous expression pattern along time. The vast majority of relative fold changes were assigned to medium (>+1.0 to ≤ +2.0 or < −1.0 to ≥ −2.0) or low (≥ −1.0 to ≤ +1.0 or ≤ 1.0 to ≥ −1.0) categories of differential expression, but for some cases such as DRR2 (8 h and 4DAI) and DEF (8 h and 10DAI), ACO and CO-MT (4DAI) or PR10 (4, 10, and 15DAI) which were assigned to the high category (>+2 or < −2) (Figure 2). Linear equations, correlation coefficients (R2) and PCR efficiencies for each gene are shown in Table 1.

Bottom Line: A total of 585 FU and 381 FD unigenes were identified, many of them involved in defense response to (a)biotic stresses.Selected genes were then used to validate libraries and evaluate their temporal expression pattern in "Frantoio." Four defense genes were analyzed in cultivars Changlot Real (tolerant) and Picual (susceptible).An association between GRAS1 and DRR2 gene expression patterns and susceptibility to VWO was observed, suggesting that these transcripts could be further evaluated as markers of the tolerance level of olive cultivars to V. dahliae.

View Article: PubMed Central - PubMed

Affiliation: Department of Crop Protection, Institute for Sustainable Agriculture, Consejo Superior de Investigaciones Científicas Córdoba, Spain.

ABSTRACT
Verticillium wilt of olive (VWO) is caused by the vascular pathogen Verticillium dahliae. One of the best VWO management measures is the use of tolerant cultivars; however, our knowledge on VWO tolerance/resistance genetics is very limited. A transcriptomic analysis was conducted to (i) identify systemic defense responses induced/repressed in aerial tissues of the tolerant cultivar Frantoio upon root colonization by V. dahliae, and (ii) determine the expression pattern of selected defense genes in olive cultivars showing differential susceptibility to VWO. Two suppression subtractive hybridization cDNA libraries, enriched in up-regulated (FU) and down-regulated (FD) genes respectively, were generated from "Frantoio" aerial tissues. Results showed that broad systemic transcriptomic changes are taking place during V. dahliae-"Frantoio" interaction. A total of 585 FU and 381 FD unigenes were identified, many of them involved in defense response to (a)biotic stresses. Selected genes were then used to validate libraries and evaluate their temporal expression pattern in "Frantoio." Four defense genes were analyzed in cultivars Changlot Real (tolerant) and Picual (susceptible). An association between GRAS1 and DRR2 gene expression patterns and susceptibility to VWO was observed, suggesting that these transcripts could be further evaluated as markers of the tolerance level of olive cultivars to V. dahliae.

No MeSH data available.


Related in: MedlinePlus