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Brassinosteroids-Induced Systemic Stress Tolerance was Associated with Increased Transcripts of Several Defence-Related Genes in the Phloem in Cucumis sativus.

Li P, Chen L, Zhou Y, Xia X, Shi K, Chen Z, Yu J - PLoS ONE (2013)

Bottom Line: Quantitative Real Time-Polymerase Chain Reaction (RT-qPCR) validated the specific up-regulation of these transcripts.Our results demonstrated that EBR-induced systemic tolerance is accompanied with increased transcript of genes in the defense response in other organs.The potential role of phloem mRNAs as signaling components in mediating BR-regulated systemic resistance is discussed.

View Article: PubMed Central - PubMed

Affiliation: Department of Horticulture, Zhejiang University, Hangzhou, People's Republic of China.

ABSTRACT
Brassinosteroids (BRs), a group of naturally occurring plant steroidal compounds, are essential for plant growth, development and stress tolerance. Recent studies showed that BRs could induce systemic tolerance to biotic and abiotic stresses; however, the molecular mechanisms by which BRs signals lead to responses in the whole plant are largely unknown. In this study, 24-epibrassinosteroid (EBR)-induced systemic tolerance in Cucumis sativus L. cv. Jinyan No. 4 was analyzed through the assessment of symptoms of photooxidative stress by chlorophyll fluorescence imaging pulse amplitude modulation. Expression of defense/stress related genes were induced in both treated local leaves and untreated systemic leaves by local EBR application. With the suppressive subtractive hybridization (SSH) library using cDNA from the phloem sap of EBR-treated plants as the tester and distilled water (DW)-treated plants as the driver, 14 transcripts out of 260 clones were identified. Quantitative Real Time-Polymerase Chain Reaction (RT-qPCR) validated the specific up-regulation of these transcripts. Of the differentially expressed transcripts with known functions, transcripts for the selected four cDNAs, which encode an auxin-responsive protein (IAA14), a putative ankyrin-repeat protein, an F-box protein (PP2), and a major latex, pathogenesis-related (MLP)-like protein, were induced in local leaves, systemic leaves and roots after foliar application of EBR onto mature leaves. Our results demonstrated that EBR-induced systemic tolerance is accompanied with increased transcript of genes in the defense response in other organs. The potential role of phloem mRNAs as signaling components in mediating BR-regulated systemic resistance is discussed.

No MeSH data available.


Related in: MedlinePlus

Validation of the up-regulated transcripts present in the SSH library by using RT-qPCR.Phloem sap was collected from stem cut close to apex and at petioles during various time intervals (3, 6, 9 and 24 h) after foliar EBR treatment. RNA was extracted from the pooled samples and relative mRNA abundances of transcripts obtained from the SSH library were determined by RT-qPCR. The data were obtained from three separate replicates, each value in the graph shows means ± SD. Asterisks (*) indicate a significant difference from the untreated control at P≤0.05 according to Tukey’s test.
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pone-0066582-g003: Validation of the up-regulated transcripts present in the SSH library by using RT-qPCR.Phloem sap was collected from stem cut close to apex and at petioles during various time intervals (3, 6, 9 and 24 h) after foliar EBR treatment. RNA was extracted from the pooled samples and relative mRNA abundances of transcripts obtained from the SSH library were determined by RT-qPCR. The data were obtained from three separate replicates, each value in the graph shows means ± SD. Asterisks (*) indicate a significant difference from the untreated control at P≤0.05 according to Tukey’s test.

Mentions: RT-qPCR was then performed to verify the up-regulation of the transcripts obtained from the SSH library. Nine clones were selected for the additional RT-qPCR analysis (Figure 3). The results indicated that the transcript levels of Cs623 (coding for an MLP-like protein), Cs60 (coding for a microtubule-binding protein), Cs642 (coding for a ribosomal protein) and Cs564 (coding for a DNA-binding protein) increased by 1.5–2-fold in the EBR-treated phloem sap. Additionally, the up-regulated defense-related transcripts, Cs453 (coding for IAA14), Cs579 (coding for a putative ankyrin-repeat protein), and Cs594 (coding for an F-box family protein), were shown to be increased by 2–4-fold. Transcript Cs681 (coding for a putative Yippee-like zinc binding protein) did not increase significantly (p-value≤0.05), this may be caused by the variation between different batches of samples. Above all, these results demonstrated that the SSH library produced reliable results.


Brassinosteroids-Induced Systemic Stress Tolerance was Associated with Increased Transcripts of Several Defence-Related Genes in the Phloem in Cucumis sativus.

Li P, Chen L, Zhou Y, Xia X, Shi K, Chen Z, Yu J - PLoS ONE (2013)

Validation of the up-regulated transcripts present in the SSH library by using RT-qPCR.Phloem sap was collected from stem cut close to apex and at petioles during various time intervals (3, 6, 9 and 24 h) after foliar EBR treatment. RNA was extracted from the pooled samples and relative mRNA abundances of transcripts obtained from the SSH library were determined by RT-qPCR. The data were obtained from three separate replicates, each value in the graph shows means ± SD. Asterisks (*) indicate a significant difference from the untreated control at P≤0.05 according to Tukey’s test.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3686678&req=5

pone-0066582-g003: Validation of the up-regulated transcripts present in the SSH library by using RT-qPCR.Phloem sap was collected from stem cut close to apex and at petioles during various time intervals (3, 6, 9 and 24 h) after foliar EBR treatment. RNA was extracted from the pooled samples and relative mRNA abundances of transcripts obtained from the SSH library were determined by RT-qPCR. The data were obtained from three separate replicates, each value in the graph shows means ± SD. Asterisks (*) indicate a significant difference from the untreated control at P≤0.05 according to Tukey’s test.
Mentions: RT-qPCR was then performed to verify the up-regulation of the transcripts obtained from the SSH library. Nine clones were selected for the additional RT-qPCR analysis (Figure 3). The results indicated that the transcript levels of Cs623 (coding for an MLP-like protein), Cs60 (coding for a microtubule-binding protein), Cs642 (coding for a ribosomal protein) and Cs564 (coding for a DNA-binding protein) increased by 1.5–2-fold in the EBR-treated phloem sap. Additionally, the up-regulated defense-related transcripts, Cs453 (coding for IAA14), Cs579 (coding for a putative ankyrin-repeat protein), and Cs594 (coding for an F-box family protein), were shown to be increased by 2–4-fold. Transcript Cs681 (coding for a putative Yippee-like zinc binding protein) did not increase significantly (p-value≤0.05), this may be caused by the variation between different batches of samples. Above all, these results demonstrated that the SSH library produced reliable results.

Bottom Line: Quantitative Real Time-Polymerase Chain Reaction (RT-qPCR) validated the specific up-regulation of these transcripts.Our results demonstrated that EBR-induced systemic tolerance is accompanied with increased transcript of genes in the defense response in other organs.The potential role of phloem mRNAs as signaling components in mediating BR-regulated systemic resistance is discussed.

View Article: PubMed Central - PubMed

Affiliation: Department of Horticulture, Zhejiang University, Hangzhou, People's Republic of China.

ABSTRACT
Brassinosteroids (BRs), a group of naturally occurring plant steroidal compounds, are essential for plant growth, development and stress tolerance. Recent studies showed that BRs could induce systemic tolerance to biotic and abiotic stresses; however, the molecular mechanisms by which BRs signals lead to responses in the whole plant are largely unknown. In this study, 24-epibrassinosteroid (EBR)-induced systemic tolerance in Cucumis sativus L. cv. Jinyan No. 4 was analyzed through the assessment of symptoms of photooxidative stress by chlorophyll fluorescence imaging pulse amplitude modulation. Expression of defense/stress related genes were induced in both treated local leaves and untreated systemic leaves by local EBR application. With the suppressive subtractive hybridization (SSH) library using cDNA from the phloem sap of EBR-treated plants as the tester and distilled water (DW)-treated plants as the driver, 14 transcripts out of 260 clones were identified. Quantitative Real Time-Polymerase Chain Reaction (RT-qPCR) validated the specific up-regulation of these transcripts. Of the differentially expressed transcripts with known functions, transcripts for the selected four cDNAs, which encode an auxin-responsive protein (IAA14), a putative ankyrin-repeat protein, an F-box protein (PP2), and a major latex, pathogenesis-related (MLP)-like protein, were induced in local leaves, systemic leaves and roots after foliar application of EBR onto mature leaves. Our results demonstrated that EBR-induced systemic tolerance is accompanied with increased transcript of genes in the defense response in other organs. The potential role of phloem mRNAs as signaling components in mediating BR-regulated systemic resistance is discussed.

No MeSH data available.


Related in: MedlinePlus