Chitinase production in pine callus (Pinus sylvestris L.): a defense reaction against endophytes?

• Published in: Planta 2002-04, Vol.214 (6), p.848-852
• Main Authors: Pirttilä, Anna Maria, Laukkanen, Hanna, Hohtola, Anja
• Format: Article
• Language: English
• Subjects: Antibodies; Biofilms; Biofilms - growth & development; Biological and medical sciences; Biotechnology; Blotting, Western; Callus; Chitinases - biosynthesis; Chitinases - genetics; Culture Techniques - methods; Cultured cells; Embryos; Endosymbionts; Eukaryotic cell cultures; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; Fungi - growth & development; Gene Expression Regulation, Enzymologic; Immunity, Innate - genetics; In Situ Hybridization; Lignin - biosynthesis; Lipid Peroxidation; Methods. Procedures. Technologies; Microorganisms; Microscopy, Electron, Scanning; Miscellaneous; Pathology, epidemiology, host-fungus relationships. Damages, economic importance; Phytopathology. Animal pests. Plant and forest protection; Pinus - enzymology; Pinus - genetics; Pinus - microbiology; Pinus sylvestris; Plant cells; Plant cells and fungal cells; Plant Diseases - genetics; Plant Diseases - microbiology; Plants
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/s00425-001-0709-x

In shoot tip-derived tissue cultures of Scots pine (Pinus sylvestris L.), browning and subsequent degeneration of the culture is accompanied by lipid peroxidation and lignification of cells, which are characteristic features of a plant defense reaction. Since chitinases are enzymes acting primarily in plant defense, their expression was studied in pine callus in order to elucidate the defense reaction. Chitinases were present diversely in tissue cultures originating from shoot tips and embryos of P. sylvestris, in contrast to Pinus nigra embryogenic callus, where production of chitinases or browning was not detected. Because endophytic microbes had earlier been detected in buds of Scots pine, their subsequent presence in the tissue cultures was considered a potential cause of the defense reaction. Therefore, the presence of endophytes in the tissue cultures was examined by in situ hybridization. Endophytes were found to colonize heavily in 45% of the tissue cultures of P. sylvestris and to form biofilms, while the P. nigra callus was not found to contain any microbes. The endophytes seemed to propagate uncontrollably once a tissue culture of P. sylvestris was initiated. Regardless of the high level of chitinase production in the callus, the control of the endophytes presumably becomes inadequate during the tissue culture of P. sylvestris.