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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

Phenotypic and physiological responses of Lemna minor in NC, A84 and A840. a-c, the appearance of L. minor in NC, A84 and A840, respectively, red arrows showed the greensick fronds, scale bar 5 mm; d Histochemically staining of cell death, O2− and H2O2 by Evans blue, nitroblue tetrazolium (NBT) and 3,3′-diaminobenzidine (DAB), respectively; e relative growth rate (RGR) based on fronds number; f MDA contents; g-j, enzyme activity of catalase (CAT), superoxide dismutase (SOD), peroxidase (POD) and ascorbate peroxidase (APX), respectively
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Fig1: Phenotypic and physiological responses of Lemna minor in NC, A84 and A840. a-c, the appearance of L. minor in NC, A84 and A840, respectively, red arrows showed the greensick fronds, scale bar 5 mm; d Histochemically staining of cell death, O2− and H2O2 by Evans blue, nitroblue tetrazolium (NBT) and 3,3′-diaminobenzidine (DAB), respectively; e relative growth rate (RGR) based on fronds number; f MDA contents; g-j, enzyme activity of catalase (CAT), superoxide dismutase (SOD), peroxidase (POD) and ascorbate peroxidase (APX), respectively

Mentions: Figure 1 a-c shows changes in the appearance of L. minor fronds at the end of experiment. The fronds in NC looked green and healthy, as well as in A84. But in A840, some mother fronds looked greensick (Fig. 1 c, shown by arrow). The RGR based on fronds number showed a downward trend from NC to A840 (Fig. 1 e). This could indicate that the NH4+ concentrations of 84 mg/L affected the propagation of L. minor, and the much higher concentration of 840 mg/L significantly inhibited the growth and could cause some damage.Fig. 1


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)

Phenotypic and physiological responses of Lemna minor in NC, A84 and A840. a-c, the appearance of L. minor in NC, A84 and A840, respectively, red arrows showed the greensick fronds, scale bar 5 mm; d Histochemically staining of cell death, O2− and H2O2 by Evans blue, nitroblue tetrazolium (NBT) and 3,3′-diaminobenzidine (DAB), respectively; e relative growth rate (RGR) based on fronds number; f MDA contents; g-j, enzyme activity of catalase (CAT), superoxide dismutase (SOD), peroxidase (POD) and ascorbate peroxidase (APX), respectively
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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

Fig1: Phenotypic and physiological responses of Lemna minor in NC, A84 and A840. a-c, the appearance of L. minor in NC, A84 and A840, respectively, red arrows showed the greensick fronds, scale bar 5 mm; d Histochemically staining of cell death, O2− and H2O2 by Evans blue, nitroblue tetrazolium (NBT) and 3,3′-diaminobenzidine (DAB), respectively; e relative growth rate (RGR) based on fronds number; f MDA contents; g-j, enzyme activity of catalase (CAT), superoxide dismutase (SOD), peroxidase (POD) and ascorbate peroxidase (APX), respectively
Mentions: Figure 1 a-c shows changes in the appearance of L. minor fronds at the end of experiment. The fronds in NC looked green and healthy, as well as in A84. But in A840, some mother fronds looked greensick (Fig. 1 c, shown by arrow). The RGR based on fronds number showed a downward trend from NC to A840 (Fig. 1 e). This could indicate that the NH4+ concentrations of 84 mg/L affected the propagation of L. minor, and the much higher concentration of 840 mg/L significantly inhibited the growth and could cause some damage.Fig. 1

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