Sultr4;1 mutant seeds of Arabidopsis have an enhanced sulphate content and modified proteome suggesting metabolic adaptations to altered sulphate compartmentalization.

Hélène Zuber (1) , Jean-Claude Davidian (2) , Markus Wirtz (3) , Rüdiger Hell (4) , Maya Belghazi (5) , Richard Thompson (1) , Karine Gallardo (1)

1 UMR 102 - Génétique et Ecophysiologie des Légumineuses à Graines (UMRLEG)
2 BPMP - Biochimie et Physiologie Moléculaire des Plantes
3 Heidelberg Institute of Plant Sciences
4 Department of Plant Molecular Biology
5 CRN2M - Centre de recherche en neurobiologie - neurophysiologie de Marseille

BACKGROUND: Sulphur is an essential macronutrient needed for the synthesis of many cellular components. Sulphur containing amino acids and stress response-related compounds, such as glutathione, are derived from reduction of root-absorbed sulphate. Sulphate distribution in cell compartments necessitates specific transport systems. The low-affinity sulphate transporters SULTR4;1 and SULTR4;2 have been localized to the vacuolar membrane, where they may facilitate sulphate efflux from the vacuole. RESULTS: In the present study, we demonstrated that the Sultr4;1 gene is expressed in developing Arabidopsis seeds to a level over 10-fold higher than the Sultr4;2 gene. A characterization of dry mature seeds from a Sultr4;1 T-DNA mutant revealed a higher sulphate content, implying a function for this transporter in developing seeds. A fine dissection of the Sultr4;1 seed proteome identified 29 spots whose abundance varied compared to wild-type. Specific metabolic features characteristic of an adaptive response were revealed, such as an up-accumulation of various proteins involved in sugar metabolism and in detoxification processes. CONCLUSIONS: This study revealed a role for SULTR4;1 in determining sulphate content of mature Arabidopsis seeds. Moreover, the adaptive response of sultr4;1 mutant seeds as revealed by proteomics suggests a function of SULTR4;1 in redox homeostasis, a mechanism that has to be tightly controlled during development of orthodox seeds.

Mots clés: sulfate; vacuolar membrane; Arabidopsis; Sultr4; transcript levels

Domaines: Biologie végétale

Hélène Zuber, Jean-Claude Davidian, Markus Wirtz, Rüdiger Hell, Maya Belghazi, et al.. Sultr4;1 mutant seeds of Arabidopsis have an enhanced sulphate content and modified proteome suggesting metabolic adaptations to altered sulphate compartmentalization.. BMC Plant Biology, 2010, 10, pp.78. ⟨10.1186/1471-2229-10-78⟩. ⟨hal-00508438⟩