The Phosphate Fast-Responsive Genes PECP1 and PPsPase1 Affect Phosphocholine and Phosphoethanolamine Content

Mohamed Hanchi (1, 2) , Marie-Christine Thibaud (1, 2) , Bertrand Legeret (1, 3) , Keiko Kuwata (4) , Nathalie Pochon (1, 2) , Fred Beisson (1, 3) , Aiqin Cao (5, 6) , Laura Cuyas (1, 2) , Pascale David (1, 2) , Peter Doerner (7) , Ali Ferjani (8) , Fan Lai (7) , Yonghua Beisson (1, 3) , Jérome Mutterer (9) , Michel Philibert (1, 10) , Kashchandra Raghothama (5, 6) , Corinne Rivasseau (11, 12) , David Secco (13, 14) , James Whelan (15) , Laurent Nussaume (1, 2) , Hélène Javot (1, 2)

1 BIAM - Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB)
2 PEPSS - Plant Environmental Physiology and Stress Signaling
3 EBMP - Environnement, Bioénergie, Microalgues et Plantes
4 Nagoya University
5 Department of Horticulture and Landscape Architecture
6 Purdue University [West Lafayette]
7 Edin. - University of Edinburgh
8 Tokyo Gakugei University
9 IBMP - Institut de Biologie Moléculaire des Plantes
10 GRAP - Groupe de Recherches Appliquées en Phytotechnologie
11 BIG - Institut de Biosciences et de Biotechnologies de Grenoble (ex-IRTSV)
12 LPCV - Physiologie cellulaire et végétale
13 UWA - The University of Western Australia
14 ARC - Centre of Excellence in Plant Energy Biology
15 La Trobe University

Phosphate starvation-mediated induction of the HAD-type phosphatases PPsPase1 (AT1G73010) and PECP1 (AT1G17710) has been reported in Arabidopsis (Arabidopsis thaliana). However, little is known about their in vivo function or impact on plant responses to nutrient deficiency. The preferences of PPsPase1 and PECP1 for different substrates have been studied in vitro but require confirmation in planta. Here, we examined the in vivo function of both enzymes using a reverse genetics approach. We demonstrated that PPsPase1 and PECP1 affect plant phosphocholine and phosphoethanolamine content, but not the pyrophosphate-related phenotypes. These observations suggest that the enzymes play a similar role in planta related to the recycling of polar heads from membrane lipids that is triggered during phosphate starvation. Altering the expression of the genes encoding these enzymes had no effect on lipid composition, possibly due to compensation by other lipid recycling pathways triggered during phosphate starvation. Furthermore, our results indicated that PPsPase1 and PECP1 do not influence phosphate homeostasis, since the inactivation of these genes had no effect on phosphate content or on the induction of molecular markers related to phosphate starvation. A combination of transcriptomics and imaging analyses revealed that PPsPase1 and PECP1 display a highly dynamic expression pattern that closely mirrors the phosphate status. This temporal dynamism, combined with the wide range of induction levels, broad expression, and lack of a direct effect on Pi content and regulation, makes PPsPase1 and PECP1 useful molecular markers of the phosphate starvation response.

Domaines: Sciences du Vivant [q-bio]

Mohamed Hanchi, Marie-Christine Thibaud, Bertrand Legeret, Keiko Kuwata, Nathalie Pochon, et al.. The Phosphate Fast-Responsive Genes PECP1 and PPsPase1 Affect Phosphocholine and Phosphoethanolamine Content. Plant Physiology, 2018, 176 (4), pp.2943-2962. ⟨10.1104/pp.17.01246⟩. ⟨cea-01950857⟩