In vivo phospholipid biosynthesis in cotton cotyledons during glyoxysome enlargement

Conference · Tue May 01 04:00:00 EDT 1990 · Plant Physiology, Supplement; (USA)

OSTI ID:5850895

Chapman, K D; Trelease, R N ^[1]

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1. Arizona State Univ., Tempe (USA)

The surface are of cottonseed glyoxysomes increases about 4 fold within 36 h after imbibition. Membrane phospholipid must become available to glyoxysomes to accommodate expansion. Incubation of cotyledons (18-h-old) in 14C-choline (1 h) resulted in at least 85% recovery of 14C-phosphatidylcholine (PC) in membranes comigrating on sucrose gradients (20-59% w/w) with antimycin A-insensitive cytochrome c reductase (CCR) activity and choline- and ethanolaminephosphotransferase (CPT and EPT) activities (ER at about 24% w/w sucrose). Chase experiments with 3.4 M choline chloride for 2, 12, or 24 h led to increasing proportions of 14C-PC (36% after 24 h) recovery in mitochondria. No transfer of 14C-PC to enlarging glyoxysomes was detected. Incubations in 14C-ethanolamine yielded ER labeling after only 30 min. 14C-PE chased into mitochondria membranes more rapidly than PC (45% after 12 h), and no 14C-PE chased into glyoxysome membranes. Evidence for synthesis of 14C-PC from 14C-PE was found after 12 h chase with 1 M ethanolamine hydrochloride. Our results indicate that ER is the primary site of PC and PE synthesis in vivo and that ER contributes newly synthesized PC and PE to mitochondrial membranes but not to expanding glyoxysomal membranes. This is different from membrane biogenesis of glyoxysomes proliferating in castor bean endosperm.

• OSTI ID: 5850895
• Report Number(s): CONF-9007196--
• Conference Information: Journal Name: Plant Physiology, Supplement; (USA) Journal Volume: 93:1
• Country of Publication: United States
• Language: English

Related Subjects

550501* -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
BIOSYNTHESIS
CARBON 14 COMPOUNDS
CELL CONSTITUENTS
COTTON PLANTS
ENDOPLASMIC RETICULUM
ESTERS
IN VIVO
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LIPIDS
MAGNOLIOPHYTA
MAGNOLIOPSIDA
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
ORGANOIDS
PHOSPHOLIPIDS
PLANTS
SYNTHESIS
TRACER TECHNIQUES