The effect of phytohormones on expression of defensin gene in scots pine

Defensins are low molecular weight cysteine-rich proteins with a wide spectrum of biological activity, which are key molecules in innate plant immunity. Previously, we have cloned five defensin genes of Scots pine (Pinus sylvestris L.), namely: PsDef1, PsDef2, PsDef3, PsDef4 and PsDef5.1. In this study, we demonstrated that expression of pine defensin genes is regulated by salicylic (SA) and jasmonic (JA) acids. Thus, exoge?nous SA causes an increase in defensin gene expression from 20 to 80 %, and JA ? from 69 % to 120 %. Growth promoting plant hormones auxin (IAA) and furfurylaminopurine (FFAP) inhibited PsDef1 and PsDef4 gene expression and had no effect on the activity of homologous genes PsDef2 and PsDef3. The abscisic acid (ABA) increased the number of PsDef1 and PsDef4 transcripts by 100 % and 20 %, respectively. The gibberellic acid (GA) increased the level of PsDef4 gene expression by 65% and had no effect on the activity of other pine defensin genes. Expression of PsDef5.1 is completely suppressed by the exogenous JA, FFAP and ABA in the eight-days-old seedlings of Scots pine.