title: Developmental, organ-specific, and light-dependent expression of the tomato ribulose-1,5-bisphosphate carboxylase small subunit gene family.
abstract: The tomato gene family for the small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase [3-phospho-D-glycerate carboxy-lyase (dimerizing); EC 4.1.1.39] has five genes, designated Rbcs-1, -2, -3A, -3B, and -3C. We have measured the steady-state mRNA levels for each of the five genes in various tomato organs using gene-specific oligonucleotides. All five genes are highly expressed in leaves, and transcripts of two genes, Rbcs-3B and Rbcs-3C, account for approximately equal to 60% of the total leaf transcripts. The relative transcript levels in the stem, in nature fruits, and etiolated seedlings (plants germinated and grown in the dark) correspond to 3.2%, 6.5%, and 4.6%, respectively, of the ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit mRNA level in leaves, and no transcripts have been detected in roots and ripe tomato fruits. Only Rbcs-1 and Rbcs-2 are expressed during the photosynthetically active phase of fruit development. Transcripts from these genes and from the Rbcs-3A locus are also present in etiolated seedlings. Rbcs-3B and Rbcs-3C transcripts, which are the most abundant mRNAs of the ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit gene family in the leaf, are undetectable in dark-grown seedlings and immature fruit. The selective expression of Rbcs-1 and Rbcs-2 in the dark and in the pericarp of green fruit and the induction and rapid mRNA accumulation for Rbcs-3B and Rbcs-3C after illumination may reflect different regulatory mechanism(s) that control the expression of individual members in the tomato ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit gene family.
mesh_terms: D004790:Enzyme Induction / Q000528:radiation effects; D005638:Fruit / Q000032:analysis; D005796:Genes; D008027:Light; D009928:Organ Specificity; D010788:Photosynthesis; D010940:Plant Proteins / Q000096:biosynthesis* / Q000235:genetics; D010944:Plants / Q000201:enzymology; D012333:RNA, Messenger / Q000096:biosynthesis; D012273:Ribulose-Bisphosphate Carboxylase / Q000096:biosynthesis* / Q000235:genetics; D012639:Seeds / Q000032:analysis
chemical_list: D010940:Plant Proteins; D012333:RNA, Messenger; D012273:Ribulose-Bisphosphate Carboxylase