Cellular response of Parachlorella kessleri to a solid surface culture environment

Frontiers in Plant Science

Plant Science

Hiroki Miyauchi¹  Mikio Tsuzuki¹  Tomoharu Ishikawa¹  Norihiro Sato¹  Atsushi Hijikata¹  Shoko Fujiwara¹  Katsuhiko Okada¹  Ayumu Sudou¹  Yutaro Hirakawa¹ 

[1] School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Japan;

关键词: attached culture;    chlorella;    gene expression;    microalgae;    photosynthesis;   

DOI  :  10.3389/fpls.2023.1175080

 received in 2023-02-27, accepted in 2023-05-02,  发布年份 2023

来源: Frontiers

【 摘 要 】

Attached culture allows high biomass productivity and is a promising biomass cultivating system because neither a huge facility area nor a large volume of culture medium are needed. This study investigates photosynthetic and transcriptomic behaviors in Parachlorella kessleri cells on a solid surface after their transfer from liquid culture to elucidate the physiological and gene-expression regulatory mechanisms that underlie their vigorous proliferation. The chlorophyll content shows a decrease at 12 h after the transfer; however, it has fully recovered at 24 h, suggesting temporary decreases in the amounts of light harvesting complexes. On PAM analysis, it is demonstrated that the effective quantum yield of PSII decreases at 0 h right after the transfer, followed by its recovery in the next 24 h. A similar changing pattern is observed for the photochemical quenching, with the PSII maximum quantum yield remaining at an almost unaltered level. Non-photochemical quenching was increased at both 0 h and 12 h after the transfer. These observations suggest that electron transfer downstream of PSII but not PSII itself is only temporarily damaged in solid-surface cells just after the transfer, with light energy in excess being dissipated as heat for PSII protection. It thus seems that the photosynthetic machinery acclimates to high-light and/or dehydration stresses through its temporal size-down and functional regulation that start right after the transfer. Meanwhile, transcriptomic analysis by RNA-Seq demonstrates temporary upregulation at 12 h after the transfer as to the expression levels of many genes for photosynthesis, amino acid synthesis, general stress response, and ribosomal subunit proteins. These findings suggest that cells transferred to a solid surface become stressed immediately after transfer but can recover their high photosynthetic activity through adaptation of photosynthetic machinery and metabolic flow as well as induction of general stress response mechanisms within 24 h.

【 授权许可】

Unknown   
Copyright © 2023 Miyauchi, Ishikawa, Hirakawa, Sudou, Okada, Hijikata, Sato, Tsuzuki and Fujiwara