Expression of Resistance Genes in Breeding Valuable Genotypes of Pine and Fast-growing Species of Birch and Poplar under Drought

Rationale. This article presents a study of the stress response to the effects of water deficiency in various genotypes of Scots pine, contrasting in seed yield, breeding genotypes of silver and downy birch, hybrids of black, white poplar and intersectional poplar hybrids. Results. A contrasting response of genotypes to the effects of drought was revealed, including activation of the pP5CS, pICDH, pNAC034, pDREB2, pCA genes in poplars 'E.s.-38', 'POK', and 'Veduga', while in black poplar the expression of all analyzed genes was reduced. In silver birch 'Ug.-1', all analyzed genes bPAL, bCA, bLEA8, bNAC19 и bDREB2 were upregulated, while in downy birch '15-1' bPAL and bNAC19 were downregulated and for the rest the changing in expression was not shown. An increase in the expression of the SAMS gene was detected in response to drought in pine genotypes of different seed production, medium-yielding No. 4 and low-yielding No. 23. For the low-yielding genotype No. 22, no changes in the expression of the analyzed genes were recorded under drought conditions. Conclusion. The results obtained indicate the development of a stress response and show differences in the adaptive response in different genotypes of pine, poplar and birch, which indicates the value of the tested genes in selection for drought conditions in different tree species.