title: Rubisco small subunit, chlorophyll a/b-binding protein and sucrose:fructan-6-fructosyl transferase gene expression and sugar status in single barley leaf cells in situ. Cell type specificity and induction by light.
abstract: We describe a highly efficient two-step single-cell reverse transcriptase-polymerase chain reaction technique for analyzing gene expression at the single-cell level. Good reproducibility and a linear dose response indicated that the technique has high specificity and sensitivity for detection and quantification of rare RNA. Actin could be used as an internal standard. The expression of message for Rubisco small subunit (RbcS), chlorophyll a/b-binding protein (Cab), sucrose (Suc):fructan-6-fructosyl transferase (6-SFT), and Actin were measured in individual photosynthetic cells of the barley (Hordeum vulgare) leaf. Only Actin was found in the non-photosynthetic epidermal cells. Cab, RbcS, and 6-SFT genes were expressed at a low level in mesophyll and parenchymatous bundle sheath (BS) cells when sampled from plants held in dark for 40 h. Expression increased considerably after illumination. The amount of 6-SFT, Cab, and RbcS transcript increased more in mesophyll cells than in the parenchymatous BS cells. The difference may be caused by different chloroplast structure and posttranscriptional control in mesophyll and BS cells. When similar single-cell samples were assayed for Suc, glucose, and fructan, there was high correlation between 6-SFT gene expression and Suc and glucose concentrations. This is consistent with Suc concentration being the trigger for transcription. Together with earlier demonstrations that the mesophyll cells have a higher sugar threshold for fructan polymerization, our data may indicate separate control of transcription and enzyme activity. Values for the sugar concentrations of the individual cell types are reported.
authors.affiliation: School of Biological Sciences, University of Wales Bangor, Bangor, Gwynedd LL57 2UW, Wales, United Kingdom.
authors.forename: Chungui
authors.initials: C
authors.lastname: Lu
authors.forename: Olga A
authors.initials: OA
authors.lastname: Koroleva
authors.forename: John F
authors.initials: JF
authors.lastname: Farrar
authors.forename: Joe
authors.initials: J
authors.lastname: Gallagher
authors.forename: Chris J
authors.initials: CJ
authors.lastname: Pollock
authors.forename: A Deri
authors.initials: AD
authors.lastname: Tomos
mesh_terms: D050260:Carbohydrate Metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000528:radiation effects; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects; D006602:Hexosyltransferases / Q000235:genetics* / Q000378:metabolism; D001467:Hordeum / Q000235:genetics* / Q000378:metabolism; D008027:Light; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics* / Q000378:metabolism; D019441:Plant Epidermis / Q000201:enzymology / Q000235:genetics; D018515:Plant Leaves / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012273:Ribulose-Bisphosphate Carboxylase / Q000235:genetics* / Q000378:metabolism; D013045:Species Specificity; D013997:Time Factors
chemical_list: D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D012333:RNA, Messenger; D006602:Hexosyltransferases; C097181:sucrose - fructan 6-fructosyltransferase; D012273:Ribulose-Bisphosphate Carboxylase