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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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Analysis of 35S::GbRLK transgenic lines subjected to ABA treatment. (a) Germination ratios of transgenic lines and Col-0 on MS medium supplemented with 0, 25, 50, 100, 200, 400 and 800 nmol/L ABA. Standard deviations (bars) are indicated. (b) Analysis of the sensitivity of 35S::GbRLK transgenic lines to MS medium supplemented with 100 nmol/L ABA at different time points. The photographs were taken after 7 and 14 days of treatment in a and b , respectively.
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Figure 5: Analysis of 35S::GbRLK transgenic lines subjected to ABA treatment. (a) Germination ratios of transgenic lines and Col-0 on MS medium supplemented with 0, 25, 50, 100, 200, 400 and 800 nmol/L ABA. Standard deviations (bars) are indicated. (b) Analysis of the sensitivity of 35S::GbRLK transgenic lines to MS medium supplemented with 100 nmol/L ABA at different time points. The photographs were taken after 7 and 14 days of treatment in a and b , respectively.

Mentions: To examine changes in the response of GbRLK transgenic plants to ABA, we investigated the ABA sensitivity of the transgenic plant. Under ABA treatment, the germination rates of the transgenic lines were greatly reduced (Figure 5a). When grown on MS medium containing 100 nmol ABA for 1, 2 and 3 weeks, the transgenic plants exhibited many abnormal phenotypes such as dwarfing, etiolation and malformation (Figure 5b). Furthermore, root elongation in the 35S::GbRLK transgenic lines was hypersensitive to ABA (data not shown). These results demonstrate that ABA suppresses seed germination, root elongation and plant growth rates more strongly in GbRLK transgenic plants than in the WT. This indicates that ABA application activates the GbRLK protein or triggers other responses in transgenic plants. In addition, these results also suggest that the GbRLK protein activates or participates in ABA-dependent signal transduction cascades or plays an important regulatory role in ABA and stress responses.


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)

Analysis of 35S::GbRLK transgenic lines subjected to ABA treatment. (a) Germination ratios of transgenic lines and Col-0 on MS medium supplemented with 0, 25, 50, 100, 200, 400 and 800 nmol/L ABA. Standard deviations (bars) are indicated. (b) Analysis of the sensitivity of 35S::GbRLK transgenic lines to MS medium supplemented with 100 nmol/L ABA at different time points. The photographs were taken after 7 and 14 days of treatment in a and b , respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 5: Analysis of 35S::GbRLK transgenic lines subjected to ABA treatment. (a) Germination ratios of transgenic lines and Col-0 on MS medium supplemented with 0, 25, 50, 100, 200, 400 and 800 nmol/L ABA. Standard deviations (bars) are indicated. (b) Analysis of the sensitivity of 35S::GbRLK transgenic lines to MS medium supplemented with 100 nmol/L ABA at different time points. The photographs were taken after 7 and 14 days of treatment in a and b , respectively.
Mentions: To examine changes in the response of GbRLK transgenic plants to ABA, we investigated the ABA sensitivity of the transgenic plant. Under ABA treatment, the germination rates of the transgenic lines were greatly reduced (Figure 5a). When grown on MS medium containing 100 nmol ABA for 1, 2 and 3 weeks, the transgenic plants exhibited many abnormal phenotypes such as dwarfing, etiolation and malformation (Figure 5b). Furthermore, root elongation in the 35S::GbRLK transgenic lines was hypersensitive to ABA (data not shown). These results demonstrate that ABA suppresses seed germination, root elongation and plant growth rates more strongly in GbRLK transgenic plants than in the WT. This indicates that ABA application activates the GbRLK protein or triggers other responses in transgenic plants. In addition, these results also suggest that the GbRLK protein activates or participates in ABA-dependent signal transduction cascades or plays an important regulatory role in ABA and stress responses.

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