ROS and reduce the toxicity. The transcriptomic
and physiological research of L. minor responding to high NH 4
+ may provide us a better
understanding not only of toxic processed but
also tolerance mechanisms (Wang et al. 2016).
Ionising radiation (IR) in the environment is
considered harmful to plants and animals when
conferring extremely high dose rates. To better
understand the physiological response to plant
exposure to ionising radiation, RNA-seq in L.
minor treated ionising radiation for seven days in
a dose rate-dependent manner was carried out.
The gene expression data revealed that L. minor
plants exposed at lower dose rates can tolerate
the exposure by triggering acclimation responses.
In contrast, the genes related to antioxidative
defense systems in terms of DNA repair and cell
cycle were high expressed at the highest dose
rate. It indicated that plants can shift from
acclimation responses toward survival responses
at increasing dose rates of ionising radiation.
Importantly, the photosynthetic process seems to
be unaffected in L. minor plants among the tested
dose rates (Van Hoeck et al. 2017).
12.6 Conclusion
In summary, in the absence of genomic data,
RNA-seq of L. punctata was powerful in
uncovering molecular mechanism under different
treatments or stresses. Especially, the transcriptome of starch metabolism mapped the transcriptional profiles of high starch, high
flavonoids, and low lignin metabolism pathways
and revealed the molecular mechanisms of high
starch accumulation under the particular conditions in duckweed. It provides new ideas for the
study of gene regulation and genetic manipulation of starch metabolism in plants.
References
Cao HX, Vu GT, Wang W et al (2014) Chromatin
organisation in duckweed interphase nuclei in relation
to the nuclear DNA content. Plant Biol (Stuttg) 17
(Suppl 1):120–124. https://doi.org/10.1111/plb.12194
Ertekin O, Kosesakal T, Unlu VS et al (2015) Phytoremediation potential of Landoltia punctata on petroleum hydrocarbons. Turk J Bot 39(1):23–29. https://
doi.org/10.3906/bot-1403-42
Fang Y, Babourina O, Rengel Z et al (2007) Ammonium
and nitrate uptake by the floating plant Landoltia
punctata. Ann Bot 99(2):365–370
Guo L, Ding Y, Xu Y et al (2017) Responses of Landoltia
punctata to cobalt and nickel: removal, growth,
photosynthesis, antioxidant system and starch metabolism. Aquat Toxicol 190:87
Huang M, Fang Y, Xiao Y et al (2014) Proteomic analysis
to investigate the high starch accumulation of duckweed (Landoltia punctata) under nutrient starvation.
Ind Crops Prod 59:299–308. https://doi.org/10.1016/j.
indcrop.2014.05.029
Les DH, Crawford DJ (1999) Landoltia (Lemnaceae), a
new genus of duckweeds. Novon J Bot Nomenclature
9(4):530–533
Liu Y, Fang Y, Huang M et al (2015a) Uniconazoleinduced starch accumulation in the bioenergy crop
duckweed (Landoltia punctata) I: transcriptome analysis of the effects of uniconazole on chlorophyll and
endogenous hormone biosynthesis. Biotechnol Biofuels 8:57. https://doi.org/10.1186/s13068-015-0246-7
Liu Y, Fang Y, Huang M et al (2015b) Uniconazoleinduced starch accumulation in the bioenergy crop
duckweed (Landoltia punctata) II: transcriptome
alterations of pathways involved in carbohydrate
metabolism and endogenous hormone crosstalk.
Biotechnol Biofuels 8:64. https://doi.org/10.1186/
s13068-015-0245-8
Nie X, Dong F, Bian L et al (2016) Uranium binding on
Landoltia punctata as a result of formation of
insoluble nano-U (VI) and U (IV) phosphate minerals.
ACS Sustain Chem Eng 5(2)
Reid MS, Bieleski RL (1970) Response of spirodelaoligorrhiza to phosphorus deficiency. Plant Physiol 46
(4):609. https://doi.org/10.1104/pp.46.4.609
Sree KS, Bog M, Appenroth KJ (2016) Taxonomy of
duckweeds (Lemnaceae), potential new crop plants.
Emirates J Food Agric 28(5):1
Stegemeier JP, Colman BP, Schwab F et al (2017) Uptake
and distribution of silver in the aquatic plant Landoltia
punctata (Duckweed) exposed to silver and silver
sulfide nanoparticles. Environ Sci Technol 51(9)
Tang J, Li Y, Wang X et al (2017) Effective adsorption of
aqueous Pb
2+ by dried biomass of Landoltia punctata
and Spirodela polyrhiza. J Clean Prod 145:25–34
Tao X, Fang Y, Xiao Y et al (2013) Comparative
transcriptome analysis to investigate the high starch
accumulation of duckweed (Landoltia punctata) under
nutrient starvation. Biotechnol Biofuels 6(1):72
Tao X, Fang Y, Huang MJ et al (2017) High flavonoid
accompanied with high starch accumulation triggered
by nutrient starvation in bioenergy crop duckweed
(Landoltia punctata). BMC Genom 18(1):166. https://
doi.org/10.1186/s12864-017-3559-z
Van Hoeck A, Horemans N, Nauts R et al (2017) Lemna
minor plants chronically exposed to ionising radiation:
130
Y. Fang et al.
and physiological research of L. minor responding to high NH 4
+ may provide us a better
understanding not only of toxic processed but
also tolerance mechanisms (Wang et al. 2016).
Ionising radiation (IR) in the environment is
considered harmful to plants and animals when
conferring extremely high dose rates. To better
understand the physiological response to plant
exposure to ionising radiation, RNA-seq in L.
minor treated ionising radiation for seven days in
a dose rate-dependent manner was carried out.
The gene expression data revealed that L. minor
plants exposed at lower dose rates can tolerate
the exposure by triggering acclimation responses.
In contrast, the genes related to antioxidative
defense systems in terms of DNA repair and cell
cycle were high expressed at the highest dose
rate. It indicated that plants can shift from
acclimation responses toward survival responses
at increasing dose rates of ionising radiation.
Importantly, the photosynthetic process seems to
be unaffected in L. minor plants among the tested
dose rates (Van Hoeck et al. 2017).
12.6 Conclusion
In summary, in the absence of genomic data,
RNA-seq of L. punctata was powerful in
uncovering molecular mechanism under different
treatments or stresses. Especially, the transcriptome of starch metabolism mapped the transcriptional profiles of high starch, high
flavonoids, and low lignin metabolism pathways
and revealed the molecular mechanisms of high
starch accumulation under the particular conditions in duckweed. It provides new ideas for the
study of gene regulation and genetic manipulation of starch metabolism in plants.
References
Cao HX, Vu GT, Wang W et al (2014) Chromatin
organisation in duckweed interphase nuclei in relation
to the nuclear DNA content. Plant Biol (Stuttg) 17
(Suppl 1):120–124. https://doi.org/10.1111/plb.12194
Ertekin O, Kosesakal T, Unlu VS et al (2015) Phytoremediation potential of Landoltia punctata on petroleum hydrocarbons. Turk J Bot 39(1):23–29. https://
doi.org/10.3906/bot-1403-42
Fang Y, Babourina O, Rengel Z et al (2007) Ammonium
and nitrate uptake by the floating plant Landoltia
punctata. Ann Bot 99(2):365–370
Guo L, Ding Y, Xu Y et al (2017) Responses of Landoltia
punctata to cobalt and nickel: removal, growth,
photosynthesis, antioxidant system and starch metabolism. Aquat Toxicol 190:87
Huang M, Fang Y, Xiao Y et al (2014) Proteomic analysis
to investigate the high starch accumulation of duckweed (Landoltia punctata) under nutrient starvation.
Ind Crops Prod 59:299–308. https://doi.org/10.1016/j.
indcrop.2014.05.029
Les DH, Crawford DJ (1999) Landoltia (Lemnaceae), a
new genus of duckweeds. Novon J Bot Nomenclature
9(4):530–533
Liu Y, Fang Y, Huang M et al (2015a) Uniconazoleinduced starch accumulation in the bioenergy crop
duckweed (Landoltia punctata) I: transcriptome analysis of the effects of uniconazole on chlorophyll and
endogenous hormone biosynthesis. Biotechnol Biofuels 8:57. https://doi.org/10.1186/s13068-015-0246-7
Liu Y, Fang Y, Huang M et al (2015b) Uniconazoleinduced starch accumulation in the bioenergy crop
duckweed (Landoltia punctata) II: transcriptome
alterations of pathways involved in carbohydrate
metabolism and endogenous hormone crosstalk.
Biotechnol Biofuels 8:64. https://doi.org/10.1186/
s13068-015-0245-8
Nie X, Dong F, Bian L et al (2016) Uranium binding on
Landoltia punctata as a result of formation of
insoluble nano-U (VI) and U (IV) phosphate minerals.
ACS Sustain Chem Eng 5(2)
Reid MS, Bieleski RL (1970) Response of spirodelaoligorrhiza to phosphorus deficiency. Plant Physiol 46
(4):609. https://doi.org/10.1104/pp.46.4.609
Sree KS, Bog M, Appenroth KJ (2016) Taxonomy of
duckweeds (Lemnaceae), potential new crop plants.
Emirates J Food Agric 28(5):1
Stegemeier JP, Colman BP, Schwab F et al (2017) Uptake
and distribution of silver in the aquatic plant Landoltia
punctata (Duckweed) exposed to silver and silver
sulfide nanoparticles. Environ Sci Technol 51(9)
Tang J, Li Y, Wang X et al (2017) Effective adsorption of
aqueous Pb
2+ by dried biomass of Landoltia punctata
and Spirodela polyrhiza. J Clean Prod 145:25–34
Tao X, Fang Y, Xiao Y et al (2013) Comparative
transcriptome analysis to investigate the high starch
accumulation of duckweed (Landoltia punctata) under
nutrient starvation. Biotechnol Biofuels 6(1):72
Tao X, Fang Y, Huang MJ et al (2017) High flavonoid
accompanied with high starch accumulation triggered
by nutrient starvation in bioenergy crop duckweed
(Landoltia punctata). BMC Genom 18(1):166. https://
doi.org/10.1186/s12864-017-3559-z
Van Hoeck A, Horemans N, Nauts R et al (2017) Lemna
minor plants chronically exposed to ionising radiation:
130
Y. Fang et al.