Indications of limited altered gene expression in Pinus sylvestris trees from the Chernobyl region

To evaluate the consequences of irradiation on the vegetation of the Chernobyl region, gene expression was compared in morphologically normal and dwarf needles from the same Pinus sylvestris trees in a region where the absorbed dose was 3–5 Gy. To compare the levels of gene expression, arrays consisting of 373 Pinus taeda cDNAs were hybridized with labeled cDNA derived from normal and dwarf needles of P. sylvestris. Twelve genes were significantly ( P < 0.01) up- or down-regulated between normal and dwarf needles for all five trees taken together. Five of these, related to stress or development, were up- or down-regulated 1.25–1.7-fold in the dwarf needles. There were no significant differences in 137Cs content in the normal and dwarf needles, or in elongation growth rate of seedlings raised under controlled conditions from seed derived from trees in the region that had received a radiation dose over the range 2–12 Gy.