Chapter 4
Carotenoid Synthesis and Accumulation
in Microalgae Under Environmental
Stress
Shota Kato and Tomoko Shinomura
Abstract In oxygenic phototrophs including cyanobacteria, algae, and land plants,
carotenoids serve the light-harvesting function together with chlorophylls and photoprotective functions. High-intensity irradiation can cause excess excitation pressure
on photo system II (PSII) of chloroplasts and can generate reactive oxygen species
resulting in the photodamage to PSII. In general, to prevent the photodamage to
photosynthetic apparatus, carotenoids dissipate excitation energy of singlet-state
chlorophylls as heat (xanthophyll-dependent non-photochemical quenching) and
also quench triplet-state chlorophylls in antenna complexes of PSII. Carotenoids
also quench singlet oxygen in the reaction center of PSII. Light is one of the
most striking environmental cues that alter the expression of carotenoid biosynthetic
genes and induce the carotenogenesis in microalgae. Light-induced accumulation of
carotenoids is reported in certain algae such as Haematococcus pluvialis, Dunaliella
salina, Chlorella zofingiensis, and Euglena gracilis. Besides light stress, various
abiotic stresses, such as heat, low temperature, drought, salinity, and oxidative stress,
can enhance the extent of photoinhibition in photosynthetic organisms and can also
induce the accumulation of carotenoids in microalgae. Here, we summarize studies
on the regulation of biosynthesis and accumulation of carotenoids in eukaryotic
microalgae in response to environmental stimuli especially focusing on the light and
temperature. In addition, here we show our recent findings on the carotenoid biosynthesis in Euglena gracilis in response to increasing light intensity and light-induced
stress enhanced by decreasing temperature.
Keywords Photoprotection · Light stress · Cold stress
S. Kato · T. Shinomura (B)
Plant Molecular and Cellular Biology Laboratory, Department of Biosciences, School of Science
and Engineering, Teikyo University, 1-1 Toyosatodai, Utsunomiya, Tochigi 320-8551, Japan
e-mail: shinomura@nasu.bio.teikyo-u.ac.jp
S. Kato
e-mail: shota.kato.680@gmail.com
S. Kato
Laboratory of Complex Biology, Center for Plant Aging Research, Institute for Basic Science,
DGIST, Daegu 42988, Republic of Korea
© Springer Nature Switzerland AG 2020
E. Jacob-Lopes et al. (eds.), Pigments from Microalgae Handbook,
https://doi.org/10.1007/978-3-030-50971-2_4
69
Carotenoid Synthesis and Accumulation
in Microalgae Under Environmental
Stress
Shota Kato and Tomoko Shinomura
Abstract In oxygenic phototrophs including cyanobacteria, algae, and land plants,
carotenoids serve the light-harvesting function together with chlorophylls and photoprotective functions. High-intensity irradiation can cause excess excitation pressure
on photo system II (PSII) of chloroplasts and can generate reactive oxygen species
resulting in the photodamage to PSII. In general, to prevent the photodamage to
photosynthetic apparatus, carotenoids dissipate excitation energy of singlet-state
chlorophylls as heat (xanthophyll-dependent non-photochemical quenching) and
also quench triplet-state chlorophylls in antenna complexes of PSII. Carotenoids
also quench singlet oxygen in the reaction center of PSII. Light is one of the
most striking environmental cues that alter the expression of carotenoid biosynthetic
genes and induce the carotenogenesis in microalgae. Light-induced accumulation of
carotenoids is reported in certain algae such as Haematococcus pluvialis, Dunaliella
salina, Chlorella zofingiensis, and Euglena gracilis. Besides light stress, various
abiotic stresses, such as heat, low temperature, drought, salinity, and oxidative stress,
can enhance the extent of photoinhibition in photosynthetic organisms and can also
induce the accumulation of carotenoids in microalgae. Here, we summarize studies
on the regulation of biosynthesis and accumulation of carotenoids in eukaryotic
microalgae in response to environmental stimuli especially focusing on the light and
temperature. In addition, here we show our recent findings on the carotenoid biosynthesis in Euglena gracilis in response to increasing light intensity and light-induced
stress enhanced by decreasing temperature.
Keywords Photoprotection · Light stress · Cold stress
S. Kato · T. Shinomura (B)
Plant Molecular and Cellular Biology Laboratory, Department of Biosciences, School of Science
and Engineering, Teikyo University, 1-1 Toyosatodai, Utsunomiya, Tochigi 320-8551, Japan
e-mail: shinomura@nasu.bio.teikyo-u.ac.jp
S. Kato
e-mail: shota.kato.680@gmail.com
S. Kato
Laboratory of Complex Biology, Center for Plant Aging Research, Institute for Basic Science,
DGIST, Daegu 42988, Republic of Korea
© Springer Nature Switzerland AG 2020
E. Jacob-Lopes et al. (eds.), Pigments from Microalgae Handbook,
https://doi.org/10.1007/978-3-030-50971-2_4
69