Microgenomic analysis reveals cell type-specific gene  expression patterns between ray and fusiform initials  within the cambial meristem of Populus.
The vascular cambium is the meristem in trees that produce wood. This meristem consists of two types of neighbouring initials: fusiform cambial cells (FCCs), which give rise to the axial cell system (i.e. fibres and vessel elements), and ray cambial cells (RCCs), which give rise to rays. There is little molecular information on the mechanisms whereby the differing characteristics of these neighbouring cells are maintained. A microgenomic approach was adopted in which the transcriptomes of FCCs and RCCs dissected out from the cambial meristem of poplar (Populus trichocarpa x Populus deltoïdes var. Boelare) were analysed, and a transcriptional database for these two cell types established. Photosynthesis genes were overrepresented in RCCs, providing molecular support for the presence of photosynthetic systems in rays. Genes that putatively encode transporters (vesicle, lipid and metal ion transporters and aquaporins) in RCCs were also identified. In addition, many cell wall-related genes showed cell type-specific expression patterns. Notably, genes involved in pectin metabolism and xyloglucan metabolism were overrepresented in RCCs and FCCs, respectively. The results demonstrate the use of microgenomics to reveal differences in biological processes in neighbouring meristematic cells, and to identify key genes involved in these processes.
Goué
Nadia
N
Institut National de la Recherche Agronomique, UAGPF, 2163 Avenue de la Pomme de Pin, BP 20619-Ardon, 45166 Olivet Cedex, France.
Lesage-Descauses
Marie-Claude
MC
Institut National de la Recherche Agronomique, UAGPF, 2163 Avenue de la Pomme de Pin, BP 20619-Ardon, 45166 Olivet Cedex, France.
Mellerowicz
Ewa J
EJ
Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, 901 83 Umeå, Sweden.
Magel
Elisabeth
E
Universität Hamburg, Zentrum Holzwirtschaft, Abteilung Holzbiologie, Leuschnerstr. 91, 21031 Hamburg, Germany.
Label
Philippe
P
Institut National de la Recherche Agronomique, UAGPF, 2163 Avenue de la Pomme de Pin, BP 20619-Ardon, 45166 Olivet Cedex, France.
Sundberg
Björn
B
Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, 901 83 Umeå, Sweden.
D001692:Biological Transport; D050260:Carbohydrate Metabolism / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics; D002473:Cell Wall / Q000378:metabolism; D030541:Databases, Genetic; D020869:Gene Expression Profiling; D023281:Genomics; D018519:Meristem / Q000235:genetics* / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D052585:Phloem / Q000378:metabolism; D010788:Photosynthesis / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D032107:Populus / Q000166:cytology / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D052584:Xylem / Q000378:metabolism
D010940:Plant Proteins; D012333:RNA, Messenger