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Transcriptomic and physiological analysis of common duckweed Lemna minor responses to NH4(+) toxicity.

Wang W, Li R, Zhu Q, Tang X, Zhao Q - BMC Plant Biol. (2016)

Bottom Line: Lemna minor, a model duckweed species, can grow well in high NH4 (+) environment but to some extent can also suffer toxic effects.A total of 6.62G nucleotides were generated from the three distinct libraries.A total of 14,207 differentially expressed genes (DEGs) among 70,728 unigenes were obtained.

View Article: PubMed Central - PubMed

Affiliation: Biogas Institute of Ministry of Agriculture, Section 4-13, Renmin Road South, Chengdu, 610041, Sichuan, PR China. wangwenguo@caas.cn.

ABSTRACT

Background: Plants can suffer ammonium (NH4 (+)) toxicity, particularly when NH4 (+) is supplied as the sole nitrogen source. However, our knowledge about the underlying mechanisms of NH4 (+) toxicity is still largely unknown. Lemna minor, a model duckweed species, can grow well in high NH4 (+) environment but to some extent can also suffer toxic effects. The transcriptomic and physiological analysis of L. minor responding to high NH4 (+) may provide us some interesting and useful information not only in toxic processes, but also in tolerance mechanisms.

Results: The L. minor cultured in the Hoagland solution were used as the control (NC), and in two NH4 (+) concentrations (NH4 (+) was the sole nitrogen source), 84 mg/L (A84) and 840 mg/L (A840) were used as stress treatments. The NH4 (+) toxicity could inhibit the growth of L. minor. Reactive oxygen species (ROS) and cell death were studied using stained fronds under toxic levels of NH4 (+). The malondialdehyde content and the activities of superoxide dismutase and peroxidase increased from NC to A840, rather than catalase and ascorbate peroxidase. A total of 6.62G nucleotides were generated from the three distinct libraries. A total of 14,207 differentially expressed genes (DEGs) among 70,728 unigenes were obtained. All the DEGs could be clustered into 7 profiles. Most DEGs were down-regulated under NH4 (+) toxicity. The genes required for lignin biosynthesis in phenylpropanoid biosynthesis pathway were up-regulated. ROS oxidative-related genes and programmed cell death (PCD)-related genes were also analyzed and indicated oxidative damage and PCD occurring under NH4 (+) toxicity.

Conclusions: The first large transcriptome study in L. minor responses to NH4 (+) toxicity was reported in this work. NH4 (+) toxicity could induce ROS accumulation that causes oxidative damage and thus induce cell death in L. minor. The antioxidant enzyme system was activated under NH4 (+) toxicity for ROS scavenging. The phenylpropanoid pathway was stimulated under NH4 (+) toxicity. The increased lignin biosynthesis might play an important role in NH4 (+) toxicity resistance.

No MeSH data available.


Related in: MedlinePlus

The expression of phenylpropanoid biosynthesis pathway genes from L. minor unigenes. a lignin and flavonoid biosynthesis in phenylpropanoid biosynthesis pathway (the numbers in the box are the RPKMs of NC, A84 and A840, respectively); b qRT-PCR analysis. PAL, Phenylalanine ammonia lyase; C4H, Cinnamic acid 4-hydroxylase; 4CL, 4-hydroxycinnamoyl-CoA ligase; HCT, Hydroxycinnamoyl-CoA: shikimate/quinate hydroxycinnamoyl transferase; CCR, Cinnamoyl-CoA reductase; C3H, p-coumaroyl shikimate 30-hydroxylase; CCoAOMT, Caffeoyl-CoA O-methyltransferase; F5H, Coniferaldehyde/ferulate 5-hydroxylase; COMT, Caffeic acid O-methyltransferase; CAD, Cinnamyl alcohol dehydrogenase; LAC, laccase; POD, Peroxidase; CHS, Chalcone synthase; CHI, Chalcone isomerase; F3H, Flavanone 3-hydroxylas; FLS, Flavonol synthase
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Fig4: The expression of phenylpropanoid biosynthesis pathway genes from L. minor unigenes. a lignin and flavonoid biosynthesis in phenylpropanoid biosynthesis pathway (the numbers in the box are the RPKMs of NC, A84 and A840, respectively); b qRT-PCR analysis. PAL, Phenylalanine ammonia lyase; C4H, Cinnamic acid 4-hydroxylase; 4CL, 4-hydroxycinnamoyl-CoA ligase; HCT, Hydroxycinnamoyl-CoA: shikimate/quinate hydroxycinnamoyl transferase; CCR, Cinnamoyl-CoA reductase; C3H, p-coumaroyl shikimate 30-hydroxylase; CCoAOMT, Caffeoyl-CoA O-methyltransferase; F5H, Coniferaldehyde/ferulate 5-hydroxylase; COMT, Caffeic acid O-methyltransferase; CAD, Cinnamyl alcohol dehydrogenase; LAC, laccase; POD, Peroxidase; CHS, Chalcone synthase; CHI, Chalcone isomerase; F3H, Flavanone 3-hydroxylas; FLS, Flavonol synthase

Mentions: In plants, the phenylpropanoid biosynthesis pathway contributes to multiple biosynthetic branches, such as lignin and flavonoid biosynthesis. The expression of transcripts encoding for key enzymes for lignin and flavonoid biosynthesis were analyzed in this study (Fig. 4). The results showed that most of lignin biosynthesis related genes were up-regulated, but not for the expression of transcripts encoding for key enzymes for flavonoid synthesis.Fig. 4


Transcriptomic and physiological analysis of common duckweed Lemna minor responses to NH4(+) toxicity.

Wang W, Li R, Zhu Q, Tang X, Zhao Q - BMC Plant Biol. (2016)

The expression of phenylpropanoid biosynthesis pathway genes from L. minor unigenes. a lignin and flavonoid biosynthesis in phenylpropanoid biosynthesis pathway (the numbers in the box are the RPKMs of NC, A84 and A840, respectively); b qRT-PCR analysis. PAL, Phenylalanine ammonia lyase; C4H, Cinnamic acid 4-hydroxylase; 4CL, 4-hydroxycinnamoyl-CoA ligase; HCT, Hydroxycinnamoyl-CoA: shikimate/quinate hydroxycinnamoyl transferase; CCR, Cinnamoyl-CoA reductase; C3H, p-coumaroyl shikimate 30-hydroxylase; CCoAOMT, Caffeoyl-CoA O-methyltransferase; F5H, Coniferaldehyde/ferulate 5-hydroxylase; COMT, Caffeic acid O-methyltransferase; CAD, Cinnamyl alcohol dehydrogenase; LAC, laccase; POD, Peroxidase; CHS, Chalcone synthase; CHI, Chalcone isomerase; F3H, Flavanone 3-hydroxylas; FLS, Flavonol synthase
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4835947&req=5

Fig4: The expression of phenylpropanoid biosynthesis pathway genes from L. minor unigenes. a lignin and flavonoid biosynthesis in phenylpropanoid biosynthesis pathway (the numbers in the box are the RPKMs of NC, A84 and A840, respectively); b qRT-PCR analysis. PAL, Phenylalanine ammonia lyase; C4H, Cinnamic acid 4-hydroxylase; 4CL, 4-hydroxycinnamoyl-CoA ligase; HCT, Hydroxycinnamoyl-CoA: shikimate/quinate hydroxycinnamoyl transferase; CCR, Cinnamoyl-CoA reductase; C3H, p-coumaroyl shikimate 30-hydroxylase; CCoAOMT, Caffeoyl-CoA O-methyltransferase; F5H, Coniferaldehyde/ferulate 5-hydroxylase; COMT, Caffeic acid O-methyltransferase; CAD, Cinnamyl alcohol dehydrogenase; LAC, laccase; POD, Peroxidase; CHS, Chalcone synthase; CHI, Chalcone isomerase; F3H, Flavanone 3-hydroxylas; FLS, Flavonol synthase
Mentions: In plants, the phenylpropanoid biosynthesis pathway contributes to multiple biosynthetic branches, such as lignin and flavonoid biosynthesis. The expression of transcripts encoding for key enzymes for lignin and flavonoid biosynthesis were analyzed in this study (Fig. 4). The results showed that most of lignin biosynthesis related genes were up-regulated, but not for the expression of transcripts encoding for key enzymes for flavonoid synthesis.Fig. 4

Bottom Line: Lemna minor, a model duckweed species, can grow well in high NH4 (+) environment but to some extent can also suffer toxic effects.A total of 6.62G nucleotides were generated from the three distinct libraries.A total of 14,207 differentially expressed genes (DEGs) among 70,728 unigenes were obtained.

View Article: PubMed Central - PubMed

Affiliation: Biogas Institute of Ministry of Agriculture, Section 4-13, Renmin Road South, Chengdu, 610041, Sichuan, PR China. wangwenguo@caas.cn.

ABSTRACT

Background: Plants can suffer ammonium (NH4 (+)) toxicity, particularly when NH4 (+) is supplied as the sole nitrogen source. However, our knowledge about the underlying mechanisms of NH4 (+) toxicity is still largely unknown. Lemna minor, a model duckweed species, can grow well in high NH4 (+) environment but to some extent can also suffer toxic effects. The transcriptomic and physiological analysis of L. minor responding to high NH4 (+) may provide us some interesting and useful information not only in toxic processes, but also in tolerance mechanisms.

Results: The L. minor cultured in the Hoagland solution were used as the control (NC), and in two NH4 (+) concentrations (NH4 (+) was the sole nitrogen source), 84 mg/L (A84) and 840 mg/L (A840) were used as stress treatments. The NH4 (+) toxicity could inhibit the growth of L. minor. Reactive oxygen species (ROS) and cell death were studied using stained fronds under toxic levels of NH4 (+). The malondialdehyde content and the activities of superoxide dismutase and peroxidase increased from NC to A840, rather than catalase and ascorbate peroxidase. A total of 6.62G nucleotides were generated from the three distinct libraries. A total of 14,207 differentially expressed genes (DEGs) among 70,728 unigenes were obtained. All the DEGs could be clustered into 7 profiles. Most DEGs were down-regulated under NH4 (+) toxicity. The genes required for lignin biosynthesis in phenylpropanoid biosynthesis pathway were up-regulated. ROS oxidative-related genes and programmed cell death (PCD)-related genes were also analyzed and indicated oxidative damage and PCD occurring under NH4 (+) toxicity.

Conclusions: The first large transcriptome study in L. minor responses to NH4 (+) toxicity was reported in this work. NH4 (+) toxicity could induce ROS accumulation that causes oxidative damage and thus induce cell death in L. minor. The antioxidant enzyme system was activated under NH4 (+) toxicity for ROS scavenging. The phenylpropanoid pathway was stimulated under NH4 (+) toxicity. The increased lignin biosynthesis might play an important role in NH4 (+) toxicity resistance.

No MeSH data available.


Related in: MedlinePlus