Chromoplast development in ripening tomato fruit: identification of cDNAs for chromoplast-targeted proteins and characterization of a cDNA encoding a plastid-localized low-molecular-weight heat shock protein.
During tomato fruit ripening, photosynthetically competent thylakoid membranes are broken down and replaced by membranous deposits of carotenoids. Few of the proteins involved in this transition have been identified. We have used chloroplast protein import assays as a means to identify two cDNAs that encode proteins destined for the developing chromoplast. One of the cDNAs had unexpected properties and its biological function has not been determined. However, the other cDNA encodes a plastid-localized low-MW heat shock protein (hsp). The steady-state level of RNA corresponding to this cDNA increased several-fold during tomato ripening, and the amount of RNA induced by heat stress increased dramatically during this process. These observations suggest a new role for this stress protein in protecting the plastid during the dismantling of the thylakoid membranes or during the buildup of carotenoids.
Lawrence
S D
SD
Department of Horticultural Sciences, Institute of Food and Agricultural Sciences, University of Florida, Gainesville 32611, USA.
Cline
K
K
Moore
G A
GA
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000302:isolation & purification*; D005638:Fruit / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D006360:Heat-Shock Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000502:physiology; D018551:Solanum lycopersicum / Q000235:genetics* / Q000254:growth & development; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010770:Phosphotransferases; D010940:Plant Proteins; D018087:Plastids / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D014158:Transcription, Genetic; D015854:Up-Regulation / Q000502:physiology
D018076:DNA, Complementary; D006360:Heat-Shock Proteins; D010940:Plant Proteins; C104732:pTOM111 protein, Lycopersicon esculentum; D010770:Phosphotransferases; C104733:pTOM41 protein, Lycopersicon esculentum