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Two Groups of Thellungiella salsuginea RAVs Exhibit Distinct Responses and Sensitivity to Salt and ABA in Transgenic Arabidopsis.

Yang S, Luo C, Song Y, Wang J - PLoS ONE (2016)

Bottom Line: Under normal conditions, the germination process of all TsRAVs overexpressing transgenic seeds was inhibited with a stronger effect observed in 35S:A-TsRAVs seeds than in 35S:B-TsRAVs seeds.All 35S:TsRAVs transgenic plants showed a similar degree of reduction in root growth compared with untreated seedlings in the presence of ABA.Taken together, our results suggest that two groups of TsRAVs perform distinct regulating roles during plant growth and abiotic defense including drought and salt, and A-TsRAVs are more likely than B-TsRAVs to act as negative regulators in the above-mentioned biological processes.

View Article: PubMed Central - PubMed

Affiliation: School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China.

ABSTRACT
Containing both AP2 domain and B3 domain, RAV (Related to ABI3/VP1) transcription factors are involved in diverse functions in higher plants. A total of eight TsRAV genes were isolated from the genome of Thellungiella salsuginea and could be divided into two groups (A- and B-group) based on their sequence similarity. The mRNA abundance of all Thellungiella salsuginea TsRAVs followed a gradual decline during seed germination. In Thellungiella salsuginea seedling, transcripts of TsRAVs in the group A (A-TsRAVs) were gradually and moderately reduced by salt treatment but rapidly and severely repressed by ABA treatment. In comparison, with a barely detectable constitutive expression, the transcriptional level of TsRAVs in the group B (B-TsRAVs) exhibited a moderate induction in cotyledons when confronted with ABA. We then produced the "gain-of-function" transgenic Arabidopsis plants for each TsRAV gene and found that only 35S:A-TsRAVs showed weak growth retardation including reduced root elongation, suggesting their roles in negatively controlling plant growth. Under normal conditions, the germination process of all TsRAVs overexpressing transgenic seeds was inhibited with a stronger effect observed in 35S:A-TsRAVs seeds than in 35S:B-TsRAVs seeds. With the presence of NaCl, seed germination and seedling root elongation of all plants including wild type and 35S:TsRAVs plants were retarded and a more severe inhibition occurred to the 35S:A-TsRAV transgenic plants. ABA treatment only negatively affected the germination rates of 35S:A-TsRAV transgenic seeds but not those of 35S:B-TsRAV transgenic seeds. All 35S:TsRAVs transgenic plants showed a similar degree of reduction in root growth compared with untreated seedlings in the presence of ABA. Furthermore, the cotyledon greening/expansion was more severely inhibited 35S:A-TsRAVs than in 35S:B-TsRAVs seedlings. Upon water deficiency, with a wider opening of stomata, 35S:A-TsRAVs plants experienced a faster transpirational water loss than wild type and 35S:B-TsRAVs lines. Taken together, our results suggest that two groups of TsRAVs perform distinct regulating roles during plant growth and abiotic defense including drought and salt, and A-TsRAVs are more likely than B-TsRAVs to act as negative regulators in the above-mentioned biological processes.

No MeSH data available.


Related in: MedlinePlus

Expression of TsRAV genes during seed germination and in response to salt and ABA treatments.(A) qRT-PCR assay of TsRAVs transcription in Thellungiella salsuginea during seed germination. Analyses were performed on seeds at 0, 2, 4, and 6 DAI (days after imbibition). The transcription levels of genes were quantified relative to that of actin. Each data bar represents the means ± SE (Standard Error) of three replicates. (B) Semi-quantitative RT-PCR assay of TsRAVs transcription in Thellungiella salsuginea seedlings upon 200 mM NaCl treatment. Total RNA was extracted at various time intervals from leaves and roots of 15-d-old seedlings. The cDNA samples are normalized using an actin gene as an internal control. (C) Semi-quantitative RT-PCR assay of TsRAVs transcription in Thellungiella salsuginea seedlings upon 5 μM ABA treatment. Total RNA was extracted at various time intervals from leaves and roots of 15-d-old seedlings. The cDNA samples are normalized using an actin gene as an internal control.
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pone.0153517.g002: Expression of TsRAV genes during seed germination and in response to salt and ABA treatments.(A) qRT-PCR assay of TsRAVs transcription in Thellungiella salsuginea during seed germination. Analyses were performed on seeds at 0, 2, 4, and 6 DAI (days after imbibition). The transcription levels of genes were quantified relative to that of actin. Each data bar represents the means ± SE (Standard Error) of three replicates. (B) Semi-quantitative RT-PCR assay of TsRAVs transcription in Thellungiella salsuginea seedlings upon 200 mM NaCl treatment. Total RNA was extracted at various time intervals from leaves and roots of 15-d-old seedlings. The cDNA samples are normalized using an actin gene as an internal control. (C) Semi-quantitative RT-PCR assay of TsRAVs transcription in Thellungiella salsuginea seedlings upon 5 μM ABA treatment. Total RNA was extracted at various time intervals from leaves and roots of 15-d-old seedlings. The cDNA samples are normalized using an actin gene as an internal control.

Mentions: We then determined the transcript level of eight TsRAV genes during Thellungiella salsuginea seed germination. It has been reported that in Arabidopsis, the expression level of AtRAV1 was very low in imbibed seed and was dramatically increased during seed germination, and its down-regulation could slowed down seed germination [15]. However, in this work, within six days after imbibition, the transcripts of all TsRAVs experienced a persistent and significant decrease until the end of the germination process, indicating that TsRAVs are negatively involved in seed germination process (Fig 2A).


Two Groups of Thellungiella salsuginea RAVs Exhibit Distinct Responses and Sensitivity to Salt and ABA in Transgenic Arabidopsis.

Yang S, Luo C, Song Y, Wang J - PLoS ONE (2016)

Expression of TsRAV genes during seed germination and in response to salt and ABA treatments.(A) qRT-PCR assay of TsRAVs transcription in Thellungiella salsuginea during seed germination. Analyses were performed on seeds at 0, 2, 4, and 6 DAI (days after imbibition). The transcription levels of genes were quantified relative to that of actin. Each data bar represents the means ± SE (Standard Error) of three replicates. (B) Semi-quantitative RT-PCR assay of TsRAVs transcription in Thellungiella salsuginea seedlings upon 200 mM NaCl treatment. Total RNA was extracted at various time intervals from leaves and roots of 15-d-old seedlings. The cDNA samples are normalized using an actin gene as an internal control. (C) Semi-quantitative RT-PCR assay of TsRAVs transcription in Thellungiella salsuginea seedlings upon 5 μM ABA treatment. Total RNA was extracted at various time intervals from leaves and roots of 15-d-old seedlings. The cDNA samples are normalized using an actin gene as an internal control.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4836749&req=5

pone.0153517.g002: Expression of TsRAV genes during seed germination and in response to salt and ABA treatments.(A) qRT-PCR assay of TsRAVs transcription in Thellungiella salsuginea during seed germination. Analyses were performed on seeds at 0, 2, 4, and 6 DAI (days after imbibition). The transcription levels of genes were quantified relative to that of actin. Each data bar represents the means ± SE (Standard Error) of three replicates. (B) Semi-quantitative RT-PCR assay of TsRAVs transcription in Thellungiella salsuginea seedlings upon 200 mM NaCl treatment. Total RNA was extracted at various time intervals from leaves and roots of 15-d-old seedlings. The cDNA samples are normalized using an actin gene as an internal control. (C) Semi-quantitative RT-PCR assay of TsRAVs transcription in Thellungiella salsuginea seedlings upon 5 μM ABA treatment. Total RNA was extracted at various time intervals from leaves and roots of 15-d-old seedlings. The cDNA samples are normalized using an actin gene as an internal control.
Mentions: We then determined the transcript level of eight TsRAV genes during Thellungiella salsuginea seed germination. It has been reported that in Arabidopsis, the expression level of AtRAV1 was very low in imbibed seed and was dramatically increased during seed germination, and its down-regulation could slowed down seed germination [15]. However, in this work, within six days after imbibition, the transcripts of all TsRAVs experienced a persistent and significant decrease until the end of the germination process, indicating that TsRAVs are negatively involved in seed germination process (Fig 2A).

Bottom Line: Under normal conditions, the germination process of all TsRAVs overexpressing transgenic seeds was inhibited with a stronger effect observed in 35S:A-TsRAVs seeds than in 35S:B-TsRAVs seeds.All 35S:TsRAVs transgenic plants showed a similar degree of reduction in root growth compared with untreated seedlings in the presence of ABA.Taken together, our results suggest that two groups of TsRAVs perform distinct regulating roles during plant growth and abiotic defense including drought and salt, and A-TsRAVs are more likely than B-TsRAVs to act as negative regulators in the above-mentioned biological processes.

View Article: PubMed Central - PubMed

Affiliation: School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China.

ABSTRACT
Containing both AP2 domain and B3 domain, RAV (Related to ABI3/VP1) transcription factors are involved in diverse functions in higher plants. A total of eight TsRAV genes were isolated from the genome of Thellungiella salsuginea and could be divided into two groups (A- and B-group) based on their sequence similarity. The mRNA abundance of all Thellungiella salsuginea TsRAVs followed a gradual decline during seed germination. In Thellungiella salsuginea seedling, transcripts of TsRAVs in the group A (A-TsRAVs) were gradually and moderately reduced by salt treatment but rapidly and severely repressed by ABA treatment. In comparison, with a barely detectable constitutive expression, the transcriptional level of TsRAVs in the group B (B-TsRAVs) exhibited a moderate induction in cotyledons when confronted with ABA. We then produced the "gain-of-function" transgenic Arabidopsis plants for each TsRAV gene and found that only 35S:A-TsRAVs showed weak growth retardation including reduced root elongation, suggesting their roles in negatively controlling plant growth. Under normal conditions, the germination process of all TsRAVs overexpressing transgenic seeds was inhibited with a stronger effect observed in 35S:A-TsRAVs seeds than in 35S:B-TsRAVs seeds. With the presence of NaCl, seed germination and seedling root elongation of all plants including wild type and 35S:TsRAVs plants were retarded and a more severe inhibition occurred to the 35S:A-TsRAV transgenic plants. ABA treatment only negatively affected the germination rates of 35S:A-TsRAV transgenic seeds but not those of 35S:B-TsRAV transgenic seeds. All 35S:TsRAVs transgenic plants showed a similar degree of reduction in root growth compared with untreated seedlings in the presence of ABA. Furthermore, the cotyledon greening/expansion was more severely inhibited 35S:A-TsRAVs than in 35S:B-TsRAVs seedlings. Upon water deficiency, with a wider opening of stomata, 35S:A-TsRAVs plants experienced a faster transpirational water loss than wild type and 35S:B-TsRAVs lines. Taken together, our results suggest that two groups of TsRAVs perform distinct regulating roles during plant growth and abiotic defense including drought and salt, and A-TsRAVs are more likely than B-TsRAVs to act as negative regulators in the above-mentioned biological processes.

No MeSH data available.


Related in: MedlinePlus