Response of somatic embryos of Scots pine to fungal cell wall elicitors
Fungal cell wall elicitors have notable effects on germination of pine seeds, defence response and many other aspects of metabolic processes. In this study, we investigated morphological, physiological and molecular response of somatic embryos of Scots pine to fungal cell wall elicitors from ectomycorrhizal fungus Suillus bovinus, pathogenic fungus Heterobasidion annosum or weak Scots pine pathogen (Heterobasidion parviporum). Results from the embryo rooting experiment indicated that the genotypic origin of the conifer tree and the source of the elicitors affected the root development. Elicitors from either S. bovinus or H. parviporum increased the root formation but increased concentration of elicitors from H. annosum decreased the rooting and survival rate of the embryos. At the molecular level, altered transcript changes were observed among genes encoding proteins involved in cell division, cell wall modification, and stress following exposure of embryos to elicitors. Increased levels of actin and peroxidase gene expression were detected at 7 days after exposure to S. bovinus or H. parviporum elicitors. H. annosum elicitors provoked significant induction of the ethylene synthesis gene PsACS-1. Generally the gene expression patterns at early stages observed in the subset of genes investigated after treatment with H. parviporum elicitor were found to be similar to that documented for S. bovinus. In contrast, somatic embryos exposed to H. annosum elicitor had different patterns of regulation marked by delayed response, and in some cases gradual degradation and death of the embryos were observed.
Document Type: Research Article
Affiliations: 1: Finnish Forest Research Institute (Metla) Punkaharju Research Unit, Finlandiantie 18, 58450 Punkaharju, Finland 2: Department of Forest Ecology, University of Helsinki, P.O. Box 27, FI-00014 Helsinki, Finland
Publication date: February 1, 2011