Early pathogenesis – specific transcriptome of root rot fungus Heterobasidion annosum

European Regional Development Fund Operational Programme "Growth and Employment" Specific Aid Objective 1.1.1 "To increase the research and innovative capacity of scientific institutions of Latvia and the ability to attract external financing, investing in human resources and infrastructure" Activity 1.1.1.2 "Post-doctoral Research Aid" agreement No. 1.1.1.2/VIAA/4/20/686

Postdoctoral researcher Maryna Ramanenka
Scientific consultant Dainis Ruņģis

H. annosum is recognised as the most important disease for Northern European forestry. This has resulted in several studies about conifer – Heterobasidion pathosystems, including research on a genomic and transcriptomic level. These genomic and transcriptomic resources provide a good background to ensure the successful outcome of the proposed study. To the best of our knowledge, no transcriptome studies of H.annosum sensu stricto during different stages of infection of P. sylvestris employing massive parallel sequencing have been published to date.

This study will identify genes important in early colonization of Scots pine and supplement the scientific data which has been previously obtained in our laboratory (H. annosum – induced changes in P. sylvestris transcriptome), forming a more complete overview of this pathosystem. The results of this project have the potential to provide new strategies for Scots pine breeding by identifying counteracting genetic factors in Scots pine. The results of this research could also provide functionally relevant markers for H. annosum population studies.

Scientific goal  is to identify H. annosum s.s. genes important in early colonisation of Scots pine and to design primers for analysis of these genes.

Impact: considering the economic and ecological importance of P. sylvestris in Northern Europe and the large economic impact of H. annosum caused damage, the results can have a positive impact in ensuring sustainability of forest ecosystems and management.

Study implementation:

1. Sample material preparation (Scots pine ramets).
2. Sampling, RNA extraction and testing.
3. Preparation of transcriptome sequencing libraries and planning of the transcriptome sequencing experiment.
4. Transcriptome sequencing and data analysis.
5. Publishing and presentation of the findings.
6. Primer design for further studies of the differentially expressed genes.
7. Public engagement and communication.

Progress

1. 3.12.2021. A sample set has been created for the study, which consists of seedlings for initial trials and  grafted material (clones) for experiments in 2022.
2. 3.12.2021. RNA was isolated from 60 seedlings (control samples and samples taken at different times after inoculation with root rot fungi).
3. 3.12.2021. Preparation of RNA samples for transcriptome sequencing was performed. Support from MGI Latvia has been promised providing free sequencing of pilot samples.
4. 14.07.2023. Manuscript "Early stage infection specific transcripts of Heterobasidion annosum in the H. annosum – Pinus sylvestris pathosystem" submitted for publication in journal Forests.

List of primer sequences for further studies of differentially expressed H. annosum genes

Summary of primer sequences