Allelic diversity of the Norway spruce leucoanthocyanidin reductase gene (PaLAR3) promoter in Belarus

The article presents the results of a genetic evaluation of the diversity of allelic variants of the PaLAR3 gene promoter, which determines some stages of flavonoid metabolism in Norway spruce (Picea abies (L.) H. Karst.). The activity of production of flavan-3,4-diol-(+)-catechin derivatives depends on the structure of the PaLAR3 gene promoter and affects the formation of resistance of Norway spruce to spruce root rot, a condition induced by the phytopathogenic fungus Heterobasidion parviporum Niemelä & Korhonen.

The experimental material for the research was collected from 950 trees of European spruce during the period 2017–2023. These trees were growing in various regions of Belarus both in forest seed plantations of the 1st and 2nd generation and in forest crops.

A molecular genetic analysis of the PaLAR3 gene promoter revealed eight amplicon size variants belonging to two major allele groups: A (A – 470 bp, A₁ – 488 bp) – susceptible phenotype of spruce to H. parviporum; B (B – 345 bp, B₁ – 342 bp, C – 376 bp, C₁ – 394 bp, D – 331 bp, and D₁ – 339 bp) – resistant phenotype. The analysis of the occurrence of allelic variants among all the trees studied showed that the susceptible A allele group (65.40 %), and A allele (62.75 %) directly had the highest representation. Group B (34.60 %), included the dominant allele variant B (32.35 %) and its rare variants, with an incidence of less than 1 %.

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