A CELLULOSE SYNTHASE (CESA) gene essential for gametophore morphogenesis in the moss Physcomitrella patens

• Published in: Planta 2012-06, Vol.235 (6), p.1355-1367
• Main Authors: Goss, Chessa A., Brockmann, Derek J., Bushoven, John T., Roberts, Alison W.
• Format: Article
• Language: English
• Subjects: Agriculture; Apical meristems; Biomedical and Life Sciences; Biosynthesis; Bryopsida - enzymology; Bryopsida - genetics; Bryopsida - growth & development; Buds; Cell growth; Cell walls; Cellulose; Cellulose - metabolism; cellulose synthase; CesA gene; CesA protein; Cytochemistry; Cytokinesis; Ecology; Forestry; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Plant; Gene Knockout Techniques; Genes, Essential - genetics; Genes, Plant - genetics; Genetic Complementation Test; Genetic vectors; Genetic Vectors - genetics; Genotype; Germ Cells, Plant - cytology; Germ Cells, Plant - growth & development; Germ Cells, Plant - metabolism; Glucosyltransferases - genetics; Glucosyltransferases - metabolism; Image processing; Leaves; Life Sciences; Meristems; Microscopy, Confocal; Microtubules; Morphogenesis; Morphogenesis - genetics; Mosses; Organogenesis; Original Article; Physcomitrella patens; Plant cells; Plant Sciences; Plants; Protoplasts; Reproducibility of Results; Restriction Mapping; Reverse Transcriptase Polymerase Chain Reaction; Seeds; Shoots; Specialization; targeted mutagenesis; Transformation, Genetic
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/s00425-011-1579-5

In seed plants, different groups of orthologous genes encode the CELLULOSE SYNTHASE (CESA) proteins that are responsible for cellulose biosynthesis in primary and secondary cell walls. The seven CESA sequences of the moss Physcomitrella patens (Hedw.) B. S. G. form a monophyletic sister group to seed plant CESAs, consistent with independent CESA diversification and specialization in moss and seed plant lines. The role of PpCESA5 in the development of P. patens was investigated by targeted mutagenesis. The cesa5 knockout lines were tested for cellulose deficiency using carbohydrate-binding module affinity cytochemistry and the morphology of the leafy gametophores was analyzed by 3D reconstruction of confocal images. No defects were identified in the development of the filamentous protonema or in production of bud initials that normally give rise to the leafy gametophores. However, the gametophore buds were cellulose deficient and defects in subsequent cell expansion, cytokinesis, and leaf initiation resulted in the formation of irregular cell clumps instead of leafy shoots. Analysis of the cesa5 knockout phenotype indicates that a biophysical model of organogenesis can be extended to the moss gametophore shoot apical meristem.