title: Sulphur nutrition affects delivery and metabolism of S in developing endosperms of wheat.
abstract: Experiments were conducted to investigate the effect of S nutrition and availability on the forms of S and N in the endosperm cavity and endosperm of wheat, and on the capacity of the endosperm to utilize those compounds for the synthesis of proteins. Plants were grown in solution culture with 2 mM N and either 200 microM S (high-S) or 50 microM S (low-S) and all nutrients were withdrawn at various times from booting until 8 d post-anthesis. Sulphate was the major form of soluble S in the endosperm cavity and endosperm of high-S plants during the time of rapid grain development. By contrast, glutathione (GSH) was the major form of soluble S in the endosperm cavity and in the endosperm in low-S plants. Crude extracts of endosperm tissue from both high-S and low-S plants supported (i) the hydrolysis of GSH to gamma-glutamyl cysteine and glycine, and of gamma-glutamyl cysteine to glutamate and cysteine, and (ii) sulphate-dependent PPi-ATP exchange and the sulphydration of O-acetylserine catalysed by ATP sulphurylase and cysteine synthase, respectively. High-S nutrition enhanced the in vitro rates of ATP sulphurylase and cysteine synthase.
authors.affiliation: School of Botany, La Trobe University, Bundoora 3083, Victoria, Australia. melissa.fitzgerald@agric.nsw.gov.au
authors.forename: M A
authors.initials: MA
authors.lastname: Fitzgerald
authors.forename: T D
authors.initials: TD
authors.lastname: Ugalde
authors.forename: J W
authors.initials: JW
authors.lastname: Anderson
mesh_terms: D000255:Adenosine Triphosphate; D003545:Cysteine / Q000378:metabolism; D003547:Cysteine Synthase / Q000378:metabolism; D005721:Glutamate-Cysteine Ligase; D018698:Glutamic Acid / Q000378:metabolism; D005978:Glutathione / Q000096:biosynthesis; D005998:Glycine / Q000378:metabolism; D009584:Nitrogen / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D012639:Seeds / Q000502:physiology*; D013431:Sulfates / Q000378:metabolism; D013455:Sulfur / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D014908:Triticum / Q000254:growth & development* / Q000378:metabolism
chemical_list: D013431:Sulfates; D018698:Glutamic Acid; D013455:Sulfur; D000255:Adenosine Triphosphate; D003547:Cysteine Synthase; D005721:Glutamate-Cysteine Ligase; D005978:Glutathione; D003545:Cysteine; D009584:Nitrogen; D005998:Glycine