Fungal Infection Increases the Rate of Somatic Mutation in Scots Pine (Pinus sylvestris L.)

• Published in: The Journal of heredity Vol. 106; no. 4; pp. 386 - 394
• Main Authors: Ranade, Sonali Sachin, Ganea, Laura-Stefana, Razzak, Abdur M, García Gil, M R
• Format: Journal Article
• Language: English
• Published: United States Oxford Publishing Limited (England) 2015
• Subjects: Basidiomycota - pathogenicity; Cronartium flaccidum; Defense mechanisms; DNA, Plant - genetics; Forest Science; Fungal infections; Genetic Markers; Genetics; Genetics, Population; Genetik; Genome, Plant; Genomic Instability; Genomics; Genotype; Genotype & phenotype; Host-Pathogen Interactions - genetics; Microsatellite Repeats; Mutation; Mutation Rate; Peridermium pini; Pinus sylvestris; Pinus sylvestris - genetics; Pinus sylvestris - microbiology; Plant diseases; Plant Diseases - genetics; Plant Diseases - microbiology; Sequence Analysis, DNA; Skogsvetenskap; Sweden; Sweden; Somatic mutation; microsatellite; Scots pine; simple sequence repeats; abiotic stress
• ISSN: 0022-1503; 1465-7333; 1465-7333
• DOI: 10.1093/jhered/esv017

Somatic mutations are transmitted during mitosis in developing somatic tissue. Somatic cells bearing the mutations can develop into reproductive (germ) cells and the somatic mutations are then passed on to the next generation of plants. Somatic mutations are a source of variation essential to evolve new defense strategies and adapt to the environment. Stem rust disease in Scots pine has a negative effect on wood quality, and thus adversely affects the economy. It is caused by the 2 most destructive fungal species in Scandinavia: Peridermium pini and Cronartium flaccidum. We studied nuclear genome stability in Scots pine under biotic stress (fungus-infected, 22 trees) compared to a control population (plantation, 20 trees). Stability was assessed as accumulation of new somatic mutations in 10 microsatellite loci selected for genotyping. Microsatellites are widely used as molecular markers in population genetics studies of plants, and are particularly used for detection of somatic mutations as their rate of mutation is of a much higher magnitude when compared with other DNA markers. We report double the rate of somatic mutation per locus in the fungus-infected trees (4.8×10(-3) mutations per locus), as compared to the controls (2.0×10(-3) mutations per locus) when individual samples were analyzed at 10 different microsatellite markers. Pearson's chi-squared test indicated a significant effect of the fungal infection which increased the number of mutations in the fungus-infected trees (χ(2) = 12.9883, df = 1, P = 0.0003134).