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A receptor-like kinase gene (GbRLK) from Gossypium barbadense enhances salinity and drought-stress tolerance in Arabidopsis.

Zhao J, Gao Y, Zhang Z, Chen T, Guo W, Zhang T - BMC Plant Biol. (2013)

Bottom Line: Transgenic Arabidopsis with constitutive overexpression of GbRLK exhibited a reduced rate of water loss in leaves in vitro, along with improved salinity and drought tolerance and increased sensitivity to ABA compared with non-transgenic Col-0 Arabidopsis.Overexpression of GbRLK may improve stress tolerance by regulating stress-responsive genes to reduce water loss.Further studying of GbRLK will help elucidate abiotic stress signaling pathways.

View Article: PubMed Central - HTML - PubMed

Affiliation: National Key Laboratory of Crop Genetics & Germplasm Enhancement, MOE Hybrid Cotton R&D Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, Jiangsu Province, China.

ABSTRACT

Background: Cotton (Gossypium spp.) is widely cultivated due to the important economic value of its fiber. However, extreme environmental degradation impedes cotton growth and production. Receptor-like kinase (RLK) proteins play important roles in signal transduction and participate in a diverse range of processes in response to plant hormones and environmental cues. Here, we introduced an RLK gene (GbRLK) from cotton into Arabidopsis and investigated its role in imparting abiotic stress tolerance.

Results: GbRLK transcription was induced by exogenously supplied abscisic acid (ABA), salicylic acid, methyl jasmonate, mock drought conditions and high salinity. We cloned the promoter sequence of this gene via self-formed adaptor PCR. Sequence analysis revealed that the promoter region contains many cis-acting stress-responsive elements such as ABRE, W-Box, MYB-core, W-Box core, TCA-element and others. We constructed a vector containing a 1,890-bp sequence in the 5' region upstream of the initiation codon of this promoter and transformed it into Arabidopsis thaliana. GUS histochemical staining analysis showed that GbRLK was expressed mainly in leaf veins, petioles and roots of transgenic Arabidopsis, but not in the cotyledons or root hairs. GbRLK promoter activity was induced by ABA, PEG, NaCl and Verticillium dahliae. Transgenic Arabidopsis with constitutive overexpression of GbRLK exhibited a reduced rate of water loss in leaves in vitro, along with improved salinity and drought tolerance and increased sensitivity to ABA compared with non-transgenic Col-0 Arabidopsis. Expression analysis of stress-responsive genes in GbRLK Arabidopsis revealed that there was increased expression of genes involved in the ABA-dependent signaling pathway (AtRD20, AtRD22 and AtRD26) and antioxidant genes (AtCAT1, AtCCS, AtCSD2 and AtCSD1) but not ion transporter genes (AtNHX1, AtSOS1).

Conclusions: GbRLK is involved in the drought and high salinity stresses pathway by activating or participating in the ABA signaling pathway. Overexpression of GbRLK may improve stress tolerance by regulating stress-responsive genes to reduce water loss. GbRLK may be employed in the genetic engineering of novel cotton cultivars in the future. Further studying of GbRLK will help elucidate abiotic stress signaling pathways.

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Histochemical straining and measurement of GUS activity in transgenic Arabidopsis thaliana. (a) a: 3-day-old seedling; b: 7-day-old seedling; c: mature leaf; d: root; e: microscopically observed root; f, g, i: transgenic plants treated with 100 μM ABA for 4 h; h: stomata before treatment with ABA; j: the CaMV 35S (pCAMBIA1301 vector) transformants as the positive control; k: non-transgenic Col-0 as the negative control. (b) GUS activity driven by the GbRLK promoter in above-ground tissues of transgenic Arabidopsis in response to ABA, PEG, NaCl and Verticillium dahliae. GUS activity from the CaMV 35S (pCAMBIA1301 vector) transformants served as the control. Data are mean and standard deviations of three replicates. The numbers below the bars indicate the -fold changes in GUS activity. Standard deviations (bars) are indicated. Significance of the changes produced after each treatment was assessed using Student’s t-tests (*P < 0.05, **P < 0.01).
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Figure 3: Histochemical straining and measurement of GUS activity in transgenic Arabidopsis thaliana. (a) a: 3-day-old seedling; b: 7-day-old seedling; c: mature leaf; d: root; e: microscopically observed root; f, g, i: transgenic plants treated with 100 μM ABA for 4 h; h: stomata before treatment with ABA; j: the CaMV 35S (pCAMBIA1301 vector) transformants as the positive control; k: non-transgenic Col-0 as the negative control. (b) GUS activity driven by the GbRLK promoter in above-ground tissues of transgenic Arabidopsis in response to ABA, PEG, NaCl and Verticillium dahliae. GUS activity from the CaMV 35S (pCAMBIA1301 vector) transformants served as the control. Data are mean and standard deviations of three replicates. The numbers below the bars indicate the -fold changes in GUS activity. Standard deviations (bars) are indicated. Significance of the changes produced after each treatment was assessed using Student’s t-tests (*P < 0.05, **P < 0.01).

Mentions: The 1,890-bp fragment (Additional file2: Figure S1b) on the 5′ region upstream of the initiation codon of the GbRLK promoter transferred into Arabidopsis to address the regulatory mechanisms employed by the GbRLK promoter. The resulting transgenic Arabidopsis lines were designated P-1890/GUS. Histochemical staining revealed that GUS expression occurred mainly in the vascular bundles (Figure 3a-e) and was strictly confined to the leaf veins (Figure 3a-b), petioles (Figure 3a-c) and roots (Figure 3a-d,e), but not or very low in the cotyledons (Figure 3a-a) or root hairs (Figure 3a-d) of transgenic Arabidopsis (Figure 3a). Therefore, the GbRLK promoter displayed a tissue-specific expression pattern. This differed from the expression pattern in plants transformed with the cauliflower mosaic virus 35S (CaMV 35S) promoter controlling GUS, which served as a positive control. These plants exhibited constitutive GUS expression (Figure 3a-j,k).


A receptor-like kinase gene (GbRLK) from Gossypium barbadense enhances salinity and drought-stress tolerance in Arabidopsis.

Zhao J, Gao Y, Zhang Z, Chen T, Guo W, Zhang T - BMC Plant Biol. (2013)

Histochemical straining and measurement of GUS activity in transgenic Arabidopsis thaliana. (a) a: 3-day-old seedling; b: 7-day-old seedling; c: mature leaf; d: root; e: microscopically observed root; f, g, i: transgenic plants treated with 100 μM ABA for 4 h; h: stomata before treatment with ABA; j: the CaMV 35S (pCAMBIA1301 vector) transformants as the positive control; k: non-transgenic Col-0 as the negative control. (b) GUS activity driven by the GbRLK promoter in above-ground tissues of transgenic Arabidopsis in response to ABA, PEG, NaCl and Verticillium dahliae. GUS activity from the CaMV 35S (pCAMBIA1301 vector) transformants served as the control. Data are mean and standard deviations of three replicates. The numbers below the bars indicate the -fold changes in GUS activity. Standard deviations (bars) are indicated. Significance of the changes produced after each treatment was assessed using Student’s t-tests (*P < 0.05, **P < 0.01).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3750506&req=5

Figure 3: Histochemical straining and measurement of GUS activity in transgenic Arabidopsis thaliana. (a) a: 3-day-old seedling; b: 7-day-old seedling; c: mature leaf; d: root; e: microscopically observed root; f, g, i: transgenic plants treated with 100 μM ABA for 4 h; h: stomata before treatment with ABA; j: the CaMV 35S (pCAMBIA1301 vector) transformants as the positive control; k: non-transgenic Col-0 as the negative control. (b) GUS activity driven by the GbRLK promoter in above-ground tissues of transgenic Arabidopsis in response to ABA, PEG, NaCl and Verticillium dahliae. GUS activity from the CaMV 35S (pCAMBIA1301 vector) transformants served as the control. Data are mean and standard deviations of three replicates. The numbers below the bars indicate the -fold changes in GUS activity. Standard deviations (bars) are indicated. Significance of the changes produced after each treatment was assessed using Student’s t-tests (*P < 0.05, **P < 0.01).
Mentions: The 1,890-bp fragment (Additional file2: Figure S1b) on the 5′ region upstream of the initiation codon of the GbRLK promoter transferred into Arabidopsis to address the regulatory mechanisms employed by the GbRLK promoter. The resulting transgenic Arabidopsis lines were designated P-1890/GUS. Histochemical staining revealed that GUS expression occurred mainly in the vascular bundles (Figure 3a-e) and was strictly confined to the leaf veins (Figure 3a-b), petioles (Figure 3a-c) and roots (Figure 3a-d,e), but not or very low in the cotyledons (Figure 3a-a) or root hairs (Figure 3a-d) of transgenic Arabidopsis (Figure 3a). Therefore, the GbRLK promoter displayed a tissue-specific expression pattern. This differed from the expression pattern in plants transformed with the cauliflower mosaic virus 35S (CaMV 35S) promoter controlling GUS, which served as a positive control. These plants exhibited constitutive GUS expression (Figure 3a-j,k).

Bottom Line: Transgenic Arabidopsis with constitutive overexpression of GbRLK exhibited a reduced rate of water loss in leaves in vitro, along with improved salinity and drought tolerance and increased sensitivity to ABA compared with non-transgenic Col-0 Arabidopsis.Overexpression of GbRLK may improve stress tolerance by regulating stress-responsive genes to reduce water loss.Further studying of GbRLK will help elucidate abiotic stress signaling pathways.

View Article: PubMed Central - HTML - PubMed

Affiliation: National Key Laboratory of Crop Genetics & Germplasm Enhancement, MOE Hybrid Cotton R&D Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, Jiangsu Province, China.

ABSTRACT

Background: Cotton (Gossypium spp.) is widely cultivated due to the important economic value of its fiber. However, extreme environmental degradation impedes cotton growth and production. Receptor-like kinase (RLK) proteins play important roles in signal transduction and participate in a diverse range of processes in response to plant hormones and environmental cues. Here, we introduced an RLK gene (GbRLK) from cotton into Arabidopsis and investigated its role in imparting abiotic stress tolerance.

Results: GbRLK transcription was induced by exogenously supplied abscisic acid (ABA), salicylic acid, methyl jasmonate, mock drought conditions and high salinity. We cloned the promoter sequence of this gene via self-formed adaptor PCR. Sequence analysis revealed that the promoter region contains many cis-acting stress-responsive elements such as ABRE, W-Box, MYB-core, W-Box core, TCA-element and others. We constructed a vector containing a 1,890-bp sequence in the 5' region upstream of the initiation codon of this promoter and transformed it into Arabidopsis thaliana. GUS histochemical staining analysis showed that GbRLK was expressed mainly in leaf veins, petioles and roots of transgenic Arabidopsis, but not in the cotyledons or root hairs. GbRLK promoter activity was induced by ABA, PEG, NaCl and Verticillium dahliae. Transgenic Arabidopsis with constitutive overexpression of GbRLK exhibited a reduced rate of water loss in leaves in vitro, along with improved salinity and drought tolerance and increased sensitivity to ABA compared with non-transgenic Col-0 Arabidopsis. Expression analysis of stress-responsive genes in GbRLK Arabidopsis revealed that there was increased expression of genes involved in the ABA-dependent signaling pathway (AtRD20, AtRD22 and AtRD26) and antioxidant genes (AtCAT1, AtCCS, AtCSD2 and AtCSD1) but not ion transporter genes (AtNHX1, AtSOS1).

Conclusions: GbRLK is involved in the drought and high salinity stresses pathway by activating or participating in the ABA signaling pathway. Overexpression of GbRLK may improve stress tolerance by regulating stress-responsive genes to reduce water loss. GbRLK may be employed in the genetic engineering of novel cotton cultivars in the future. Further studying of GbRLK will help elucidate abiotic stress signaling pathways.

Show MeSH
Related in: MedlinePlus