Limits...
The Stable Level of Glutamine synthetase 2 Plays an Important Role in Rice Growth and in Carbon-Nitrogen Metabolic Balance.

Bao A, Zhao Z, Ding G, Shi L, Xu F, Cai H - Int J Mol Sci (2015)

Bottom Line: The results revealed that the GS2-cosuppressed plants exhibited a poor plant growth phenotype and a poor nitrogen transport ability, which led to nitrogen accumulation and a decline in the carbon/nitrogen ratio in the stems.Interestingly, there was a higher concentration of soluble proteins and a lower concentration of carbohydrates in the GS2-cosuppressed plants at the seedling stage, while a contrasting result was displayed at the tillering stage.These results indicated the important role of a stable level of GS2 transcription during normal rice development and the importance of the carbon-nitrogen metabolic balance in rice growth.

View Article: PubMed Central - PubMed

Affiliation: Microelement Research Center, Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China. baoaili19870212@163.com.

ABSTRACT
Glutamine synthetase 2 (GS2) is a key enzyme involved in the ammonium metabolism in plant leaves. In our previous study, we obtained GS2-cosuppressed plants, which displayed a normal growth phenotype at the seedling stage, while at the tillering stage they showed a chlorosis phenotype. In this study, to investigate the chlorosis mechanism, we systematically analyzed the plant growth, carbon-nitrogen metabolism and gene expressions between the GS2-cosuppressed rice and wild-type plants. The results revealed that the GS2-cosuppressed plants exhibited a poor plant growth phenotype and a poor nitrogen transport ability, which led to nitrogen accumulation and a decline in the carbon/nitrogen ratio in the stems. Interestingly, there was a higher concentration of soluble proteins and a lower concentration of carbohydrates in the GS2-cosuppressed plants at the seedling stage, while a contrasting result was displayed at the tillering stage. The analysis of the metabolic profile showed a significant increase of sugars and organic acids. Additionally, gene expression patterns were different in root and leaf of GS2-cosuppressed plants between the seedling and tillering stage. These results indicated the important role of a stable level of GS2 transcription during normal rice development and the importance of the carbon-nitrogen metabolic balance in rice growth.

No MeSH data available.


Related in: MedlinePlus

The fold change corresponds to the ratio of the gene expression level in the GS2-cosuppressed plants relative to the wild-type plants. (A) Diagrammatic representation of the key genes involved in the carbon and nitrogen metabolic pathway in rice plants. NRT, nitrate transporter; NR, nitrate reductase; GS, glutamine synthetase; GOGAT, glutamate synthase; RUBISCO, ribulose-1,5-bisphosphate carboxylase/oxygenase; PEPC, phosphoenolpyruvate carboxylase. Prominent changes in the gene expression level in the GS2-cosuppressed plants compared to wild-type plants at the seedling stage and tillering stage under N (B), G (C) and N + G (D) conditions. Red and blue dots indicate up- and down-regulated genes, respectively.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4490469&req=5

ijms-16-12713-f006: The fold change corresponds to the ratio of the gene expression level in the GS2-cosuppressed plants relative to the wild-type plants. (A) Diagrammatic representation of the key genes involved in the carbon and nitrogen metabolic pathway in rice plants. NRT, nitrate transporter; NR, nitrate reductase; GS, glutamine synthetase; GOGAT, glutamate synthase; RUBISCO, ribulose-1,5-bisphosphate carboxylase/oxygenase; PEPC, phosphoenolpyruvate carboxylase. Prominent changes in the gene expression level in the GS2-cosuppressed plants compared to wild-type plants at the seedling stage and tillering stage under N (B), G (C) and N + G (D) conditions. Red and blue dots indicate up- and down-regulated genes, respectively.

Mentions: To determine the impact of the reduced GS2 mRNA transcriptional level on the carbon-nitrogen metabolic genes’ expression patterns, we analyzed the expression level of genes encoding NRT (nitrate transporter), NR (nitrate reductase), GS (glutamine synthetase), GOGAT (glutamate synthase), RUBISCO (ribulose-1,5-bisphosphate carboxylase/oxygenase) and PEPC (phosphoenolpyruvate carboxylase) by q-RT PCR. Figure 6A displays these genes in the carbon and nitrogen metabolic pathway in rice plants. Supplementary Table S1 lists the fold change corresponding to the ratio of the gene expression level in GS2-cosuppressed plants relative to wild-type plants in the roots and leaves at both the seedling and tillering stage under N, G and N + G conditions. The results showed that the expression levels of most genes were changed in the GS2-cosuppressed plants. Compared to the wild-type plants, the significantly (p < 0.01) higher GS2 expression levels (35.06–537.49-fold) were observed in the roots of GS2-cosuppressed plants at both the seedling stage and the tillering stage under N, G and N + G conditions (Supplementary Table S1). However, significantly (p < 0.05) lower GS2 expression levels (0.43–0.79-fold) were observed in the leaves of GS2-cosuppressed plants at both the seedling stage and the tillering stage under the N, G and N + G conditions, except a higher GS2 expression level (2.35-fold) was observed in the leaves at the seedling stage under the N condition (Supplementary Table S1). Furthermore, different gene expression patterns were exhibited in the GS2-cosuppressed plants between the seedling stage and tillering stage. Additionally, opposite gene expression patterns were shown between the root and leaf tissues, particularly at the tillering stage. For example, the expression levels of the NRT1;1, NRT1;2, NRT2, NR2, GS1;2, Fd-GOGAT1 and NADH-GOGAT1 genes were significantly (p < 0.05) increased in the roots, while the expression levels of the NR1, NR2, GS1;1, GS2, Fd-GOGAT2, NADH-GOGAT2, RUBISCO, PEPC1 and PEPC2 genes were significantly (p < 0.05) decreased in the leaves under the N condition (Figure 6).


The Stable Level of Glutamine synthetase 2 Plays an Important Role in Rice Growth and in Carbon-Nitrogen Metabolic Balance.

Bao A, Zhao Z, Ding G, Shi L, Xu F, Cai H - Int J Mol Sci (2015)

The fold change corresponds to the ratio of the gene expression level in the GS2-cosuppressed plants relative to the wild-type plants. (A) Diagrammatic representation of the key genes involved in the carbon and nitrogen metabolic pathway in rice plants. NRT, nitrate transporter; NR, nitrate reductase; GS, glutamine synthetase; GOGAT, glutamate synthase; RUBISCO, ribulose-1,5-bisphosphate carboxylase/oxygenase; PEPC, phosphoenolpyruvate carboxylase. Prominent changes in the gene expression level in the GS2-cosuppressed plants compared to wild-type plants at the seedling stage and tillering stage under N (B), G (C) and N + G (D) conditions. Red and blue dots indicate up- and down-regulated genes, respectively.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4490469&req=5

ijms-16-12713-f006: The fold change corresponds to the ratio of the gene expression level in the GS2-cosuppressed plants relative to the wild-type plants. (A) Diagrammatic representation of the key genes involved in the carbon and nitrogen metabolic pathway in rice plants. NRT, nitrate transporter; NR, nitrate reductase; GS, glutamine synthetase; GOGAT, glutamate synthase; RUBISCO, ribulose-1,5-bisphosphate carboxylase/oxygenase; PEPC, phosphoenolpyruvate carboxylase. Prominent changes in the gene expression level in the GS2-cosuppressed plants compared to wild-type plants at the seedling stage and tillering stage under N (B), G (C) and N + G (D) conditions. Red and blue dots indicate up- and down-regulated genes, respectively.
Mentions: To determine the impact of the reduced GS2 mRNA transcriptional level on the carbon-nitrogen metabolic genes’ expression patterns, we analyzed the expression level of genes encoding NRT (nitrate transporter), NR (nitrate reductase), GS (glutamine synthetase), GOGAT (glutamate synthase), RUBISCO (ribulose-1,5-bisphosphate carboxylase/oxygenase) and PEPC (phosphoenolpyruvate carboxylase) by q-RT PCR. Figure 6A displays these genes in the carbon and nitrogen metabolic pathway in rice plants. Supplementary Table S1 lists the fold change corresponding to the ratio of the gene expression level in GS2-cosuppressed plants relative to wild-type plants in the roots and leaves at both the seedling and tillering stage under N, G and N + G conditions. The results showed that the expression levels of most genes were changed in the GS2-cosuppressed plants. Compared to the wild-type plants, the significantly (p < 0.01) higher GS2 expression levels (35.06–537.49-fold) were observed in the roots of GS2-cosuppressed plants at both the seedling stage and the tillering stage under N, G and N + G conditions (Supplementary Table S1). However, significantly (p < 0.05) lower GS2 expression levels (0.43–0.79-fold) were observed in the leaves of GS2-cosuppressed plants at both the seedling stage and the tillering stage under the N, G and N + G conditions, except a higher GS2 expression level (2.35-fold) was observed in the leaves at the seedling stage under the N condition (Supplementary Table S1). Furthermore, different gene expression patterns were exhibited in the GS2-cosuppressed plants between the seedling stage and tillering stage. Additionally, opposite gene expression patterns were shown between the root and leaf tissues, particularly at the tillering stage. For example, the expression levels of the NRT1;1, NRT1;2, NRT2, NR2, GS1;2, Fd-GOGAT1 and NADH-GOGAT1 genes were significantly (p < 0.05) increased in the roots, while the expression levels of the NR1, NR2, GS1;1, GS2, Fd-GOGAT2, NADH-GOGAT2, RUBISCO, PEPC1 and PEPC2 genes were significantly (p < 0.05) decreased in the leaves under the N condition (Figure 6).

Bottom Line: The results revealed that the GS2-cosuppressed plants exhibited a poor plant growth phenotype and a poor nitrogen transport ability, which led to nitrogen accumulation and a decline in the carbon/nitrogen ratio in the stems.Interestingly, there was a higher concentration of soluble proteins and a lower concentration of carbohydrates in the GS2-cosuppressed plants at the seedling stage, while a contrasting result was displayed at the tillering stage.These results indicated the important role of a stable level of GS2 transcription during normal rice development and the importance of the carbon-nitrogen metabolic balance in rice growth.

View Article: PubMed Central - PubMed

Affiliation: Microelement Research Center, Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China. baoaili19870212@163.com.

ABSTRACT
Glutamine synthetase 2 (GS2) is a key enzyme involved in the ammonium metabolism in plant leaves. In our previous study, we obtained GS2-cosuppressed plants, which displayed a normal growth phenotype at the seedling stage, while at the tillering stage they showed a chlorosis phenotype. In this study, to investigate the chlorosis mechanism, we systematically analyzed the plant growth, carbon-nitrogen metabolism and gene expressions between the GS2-cosuppressed rice and wild-type plants. The results revealed that the GS2-cosuppressed plants exhibited a poor plant growth phenotype and a poor nitrogen transport ability, which led to nitrogen accumulation and a decline in the carbon/nitrogen ratio in the stems. Interestingly, there was a higher concentration of soluble proteins and a lower concentration of carbohydrates in the GS2-cosuppressed plants at the seedling stage, while a contrasting result was displayed at the tillering stage. The analysis of the metabolic profile showed a significant increase of sugars and organic acids. Additionally, gene expression patterns were different in root and leaf of GS2-cosuppressed plants between the seedling and tillering stage. These results indicated the important role of a stable level of GS2 transcription during normal rice development and the importance of the carbon-nitrogen metabolic balance in rice growth.

No MeSH data available.


Related in: MedlinePlus