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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 four genes from aerial tissues of inoculated tolerant (“Frantoio” and “Changlot Real”) and susceptible (“Picual”) olive cultivars at two 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; Relative expression values (log2-fold-change values) were calculated according to the 2−ΔΔCt method (Livak and Schmittgen, 2001). Red and blue lines show RE scored for two different plants sampled at the indicated times after inoculation with the pathogen.
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Figure 3: Relative expression (RE) average of four genes from aerial tissues of inoculated tolerant (“Frantoio” and “Changlot Real”) and susceptible (“Picual”) olive cultivars at two 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; Relative expression values (log2-fold-change values) were calculated according to the 2−ΔΔCt method (Livak and Schmittgen, 2001). Red and blue lines show RE scored for two different plants sampled at the indicated times after inoculation with the pathogen.

Mentions: In order to compare the gene expression pattern of specific genes in different olive cultivars (“Picual,” susceptible to VWO, and “Frantoio” and “Changlot Real,” tolerant to VWO), four genes (GRAS1, ACO, DRR2, and ACL) were selected (Table 2). Their expression patterns were assessed at 2 and 10DAI. Relative expression for each gene/cultivar combination is shown in Figure 3 (see Table S5 for additional data). Time-course expression of each gene differed among cultivars but the two biological replicas (plants) tested by cultivar did not always show the same expression pattern. ACO expression displayed the same trend in “Picual” and “Changlot Real” in contrast to “Frantoio.” Indeed, this gene showed an induction trend from 2 to 10DAI, particularly in “Picual” plants, whereas it showed a trend to be repressed in “Frantoio” plants along this interval. DRR2 expression is down-regulated in tolerant cultivars but up-regulated in the susceptible “Picual,” the two plants of this cultivar showing discrepant DRR2 expression patterns though (Figure 3). Expression of GRAS1 yielded the most consistent results, this gene being down regulated in tolerant cultivars at both sampling times. On the contrary, “Picual” plants showed a sharp fall in GRAS1 expression levels along time. Finally, results for ACL gene expression were the most contentious since plants of the same cultivar (i.e., “Picual” and “Changlot Real”) showed opposite expression patterns. In contrast, the two biological replicas of “Frantoio” displayed a consistent down regulation trend from 2 to 10DAI. For this gene, however, no clear association between VWO susceptibility and expression of defense genes was found.


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 four genes from aerial tissues of inoculated tolerant (“Frantoio” and “Changlot Real”) and susceptible (“Picual”) olive cultivars at two 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; Relative expression values (log2-fold-change values) were calculated according to the 2−ΔΔCt method (Livak and Schmittgen, 2001). Red and blue lines show RE scored for two different plants sampled at the indicated times after inoculation with the pathogen.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 3: Relative expression (RE) average of four genes from aerial tissues of inoculated tolerant (“Frantoio” and “Changlot Real”) and susceptible (“Picual”) olive cultivars at two 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; Relative expression values (log2-fold-change values) were calculated according to the 2−ΔΔCt method (Livak and Schmittgen, 2001). Red and blue lines show RE scored for two different plants sampled at the indicated times after inoculation with the pathogen.
Mentions: In order to compare the gene expression pattern of specific genes in different olive cultivars (“Picual,” susceptible to VWO, and “Frantoio” and “Changlot Real,” tolerant to VWO), four genes (GRAS1, ACO, DRR2, and ACL) were selected (Table 2). Their expression patterns were assessed at 2 and 10DAI. Relative expression for each gene/cultivar combination is shown in Figure 3 (see Table S5 for additional data). Time-course expression of each gene differed among cultivars but the two biological replicas (plants) tested by cultivar did not always show the same expression pattern. ACO expression displayed the same trend in “Picual” and “Changlot Real” in contrast to “Frantoio.” Indeed, this gene showed an induction trend from 2 to 10DAI, particularly in “Picual” plants, whereas it showed a trend to be repressed in “Frantoio” plants along this interval. DRR2 expression is down-regulated in tolerant cultivars but up-regulated in the susceptible “Picual,” the two plants of this cultivar showing discrepant DRR2 expression patterns though (Figure 3). Expression of GRAS1 yielded the most consistent results, this gene being down regulated in tolerant cultivars at both sampling times. On the contrary, “Picual” plants showed a sharp fall in GRAS1 expression levels along time. Finally, results for ACL gene expression were the most contentious since plants of the same cultivar (i.e., “Picual” and “Changlot Real”) showed opposite expression patterns. In contrast, the two biological replicas of “Frantoio” displayed a consistent down regulation trend from 2 to 10DAI. For this gene, however, no clear association between VWO susceptibility and expression of defense genes was found.

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