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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

Heatmap (a) and qRT-PCR (b) analysis of the expression levels of oxidative-related and PCD-related genes. TI, Trypsin/chymotrypsin inhibitor; DNAJ, DNAJ heat shock family protein; FAD-B, FAD-binding domain-containing protein; P450 77A3, Cytochrome P450 77A3; P450 78, Cytochrome P450 85A-like; P450 85A, Cytochrome P450 85A-like; CAT, catalase; SOD-Mn, Superoxide dismutase [Mn]; SOD-Fe, Superoxide dismutase [Fe]; SOD- Cu/Zn, Cu/Zn superoxide dismutase; POD, Peroxidase; APX, L-ascorbate peroxidase; Rboh A, Respiratory burst oxidase homolog protein A; Rboh D, Respiratory burst oxidase protein D; NR, Nitrate reductase; NSHB1, Hemoglobin 1; AOX, Alternative oxidase 1; MAC4, Metacaspase 4; DAD1, Defender against cell death 1; BAXI1, BAX inhibitor 1
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Fig5: Heatmap (a) and qRT-PCR (b) analysis of the expression levels of oxidative-related and PCD-related genes. TI, Trypsin/chymotrypsin inhibitor; DNAJ, DNAJ heat shock family protein; FAD-B, FAD-binding domain-containing protein; P450 77A3, Cytochrome P450 77A3; P450 78, Cytochrome P450 85A-like; P450 85A, Cytochrome P450 85A-like; CAT, catalase; SOD-Mn, Superoxide dismutase [Mn]; SOD-Fe, Superoxide dismutase [Fe]; SOD- Cu/Zn, Cu/Zn superoxide dismutase; POD, Peroxidase; APX, L-ascorbate peroxidase; Rboh A, Respiratory burst oxidase homolog protein A; Rboh D, Respiratory burst oxidase protein D; NR, Nitrate reductase; NSHB1, Hemoglobin 1; AOX, Alternative oxidase 1; MAC4, Metacaspase 4; DAD1, Defender against cell death 1; BAXI1, BAX inhibitor 1

Mentions: Expression of the 14 ROS oxidative-related genes including six oxidative marker genes, six ROS-scavenging genes and two ROS-producing genes are summarized in Fig. 5. The oxidative marker genes included a trypsin/chymotrypsin inhibitor, a DNAJ heat shock protein, a FAD-binding protein and three cytochrome P450 genes, which are regarded as hallmarks for the general oxidative stress response [40, 41]. The ROS-scavenging genes consisted of genes of CAT, SOD and POD.Fig. 5


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)

Heatmap (a) and qRT-PCR (b) analysis of the expression levels of oxidative-related and PCD-related genes. TI, Trypsin/chymotrypsin inhibitor; DNAJ, DNAJ heat shock family protein; FAD-B, FAD-binding domain-containing protein; P450 77A3, Cytochrome P450 77A3; P450 78, Cytochrome P450 85A-like; P450 85A, Cytochrome P450 85A-like; CAT, catalase; SOD-Mn, Superoxide dismutase [Mn]; SOD-Fe, Superoxide dismutase [Fe]; SOD- Cu/Zn, Cu/Zn superoxide dismutase; POD, Peroxidase; APX, L-ascorbate peroxidase; Rboh A, Respiratory burst oxidase homolog protein A; Rboh D, Respiratory burst oxidase protein D; NR, Nitrate reductase; NSHB1, Hemoglobin 1; AOX, Alternative oxidase 1; MAC4, Metacaspase 4; DAD1, Defender against cell death 1; BAXI1, BAX inhibitor 1
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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

Fig5: Heatmap (a) and qRT-PCR (b) analysis of the expression levels of oxidative-related and PCD-related genes. TI, Trypsin/chymotrypsin inhibitor; DNAJ, DNAJ heat shock family protein; FAD-B, FAD-binding domain-containing protein; P450 77A3, Cytochrome P450 77A3; P450 78, Cytochrome P450 85A-like; P450 85A, Cytochrome P450 85A-like; CAT, catalase; SOD-Mn, Superoxide dismutase [Mn]; SOD-Fe, Superoxide dismutase [Fe]; SOD- Cu/Zn, Cu/Zn superoxide dismutase; POD, Peroxidase; APX, L-ascorbate peroxidase; Rboh A, Respiratory burst oxidase homolog protein A; Rboh D, Respiratory burst oxidase protein D; NR, Nitrate reductase; NSHB1, Hemoglobin 1; AOX, Alternative oxidase 1; MAC4, Metacaspase 4; DAD1, Defender against cell death 1; BAXI1, BAX inhibitor 1
Mentions: Expression of the 14 ROS oxidative-related genes including six oxidative marker genes, six ROS-scavenging genes and two ROS-producing genes are summarized in Fig. 5. The oxidative marker genes included a trypsin/chymotrypsin inhibitor, a DNAJ heat shock protein, a FAD-binding protein and three cytochrome P450 genes, which are regarded as hallmarks for the general oxidative stress response [40, 41]. The ROS-scavenging genes consisted of genes of CAT, SOD and POD.Fig. 5

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