Projects archive

Investigation of molecular defence mechanisms in Scots pine (Pinus sylvestris L.)
Leader: Dainis Edgars Ruņģis
Start date: 1.2.2013
End date: 30.12.2016

Funded by the Latvian Council of Science.

The purpose of this study is to investigate the molecular genetic response of Scots pine (Pinus sylvestris L.) to infection by two fungal pathogens as well as the processes of induced resistance. The study of these pathogenic fungi is very important in the forest sector - Heterobasidion annosum is the causal agent of root rot and Lophodermium seditiosum causes needle cast in young pine trees. In Scots pine, root rot is difficult to detect visually, it inhibits tree growth and can cause tree death (Šķipars & Ruņģis, 2011). Needlecast mainly affects young pine trees (up to 10 years old) and is a major problem in nurseries (Jansons et al., 2008). Resistance to both pathogens of these fungal diseases has been shown to have a genetic basis, so the results of the study can be included in pine breeding programs as selection criteria (Jansons et al., 2008; Korshikov & Demkovich, 2008).

The project will explore different aspects of Scots pine resistance by combining gene expression experiments with studies of epigenetic mechanisms that regulate and modulate defence responses. MicroRNA (miRNA) molecules participate in the regulation of gene expression by binding to target messenger RNA (mRNA) molecules, thereby inhibiting translation or completely inhibiting it. To date, retrotransposons have also been found in all studied genomes. These are DNA elements that can move from one locus to another via RNA intermediaries. The relatively large conifers genomes contain approximately 70-75% repetitive DNA sequences, including retrotransposons (Kole, 2007). The function and adaptive role of these elements has not been fully elucidated, however, it is known that these elements are activated in plants under stress conditions (Wessler, 1996). Retrotransposons and miRNA are involved in epigenetic processes, and the knowledge gained during the project will be able to be used in pine breeding programs to increase the adaptive capacity and phenotypic plasticity of selected trees.

Induced resistance is a process in plants that develops a resistance response to a pathogen or other stresses that subsequently protects the plant. This process has not been widely studied in Pinus sylvestris and the utilisation of induced resistance mechanisms may be useful to increase survival in renewed forest stands.

The described processes have not been studied in common pine (Pinus sylvestris L.). Adaptation of the methodologies developed for other conifer species will allow comparisons of these processes as well as the discovery of unique aspects in Scots pine.

Expected results of the study:

  1. Determination of changes in gene expression in Scots pine trees after inoculation with Heterobasidion annosum and Lophodermium seditiosum;
  2. Investigation of the role of miRNAs in regulation of gene expression;
  3. Investigation of the role of retrotransposons in defence responses;
  4. Investigation of induced resistance and its persistence.

Research into the molecular genetic responses of Scots pine to fungal infection will not only increase the basic knowledge of these processes and their regulation, but will also enable these results to be used in pine breeding programs.

Other researchers:

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