Two plastidial lysophosphatidic acid acyltransferases differentially mediate the biosynthesis of membrane lipids and triacylglycerols in Phaeodactylum tricornutum

Type : ACL
Nature : Production scientifique
Au bénéfice du Laboratoire : Non
Statut de publication : Publié
Année de publication : 2023
Auteurs (14) : YOU L,j POLONSKA A JASIENIECKA-GAZARKIEWICZ K RICHARD Fabien JOUHET Juliette MARÉCHAL Eric BANAS A HU H,h PAN Y,f HAO X,h JING H ALLEN Andrew,e AMATO A GONG Y,m
Revue scientifique : New Phytologist
Volume : 241
Fascicule :
Pages : 1543-1558
DOI : 10.1111/nph.19434
URL : https://doi.org/10.1111/nph.19434
Abstract : Lysophosphatidic acid acyltransferases (LPAATs) catalyze the formation of phosphatidic acid (PA), a central metabolite in both prokaryotic and eukaryotic organisms for glycerolipid biosynthesis. Phaeodactylum tricornutum contains at least two plastid-localized LPAATs (ptATS2a and ptATS2b), but their roles in lipid synthesis remain unknown. Both ptATS2a and ptATS2b could complement the high temperature sensitivity of the bacterial plsC mutant deficient in LPAAT. In vitro enzyme assays showed that they prefer lysophosphatidic acid over other lysophospholipids. ptATS2a is localized in the plastid inner envelope membrane and CRISPR/Cas9-generated ptATS2a mutants showed compromised cell growth, significantly changed plastid and extra-plastidial membrane lipids at nitrogen-replete condition and reduced triacylglycerols (TAGs) under nitrogen-depleted condition. ptATS2b is localized in thylakoid membranes and its knockout led to reduced growth rate and TAG content but slightly altered molecular composition of membrane lipids. The changes in glycerolipid profiles are consistent with the role of both LPAATs in the sn-2 acylation of sn-1-acyl-glycerol-3-phosphate substrates harboring 20:5 at the sn-1 position. Our findings suggest that both LPAATs are important for membrane lipids and TAG biosynthesis in P. tricornutum and further highlight that 20:5-Lyso-PA is likely involved in the massive import of 20:5 back to the plastid to feed plastid glycerolipid syntheses.
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You LJ, Polonska A, Jasieniecka-Gazarkiewicz K, Richard F, Jouhet J, Maréchal E, Banas A, Hu HH, Pan YF, Hao XH, Jing H, Allen AE, Amato A, Gong YM (2023) Two plastidial lysophosphatidic acid acyltransferases differentially mediate the biosynthesis of membrane lipids and triacylglycerols in Phaeodactylum tricornutum. New Phytol 241: 1543-1558 | doi: 10.1111/nph.19434