Gene induction of stilbene biosynthesis in Scots pine in response to ozonetreatment, wounding, and fungal infection

The S-adenosyl-L-methionine:pinosylvin-O-methyltransferase (PMT)(2) gene wa s sequenced from Scots pine (Pinus sylvestris). The open reading frame is a rranged in two exons spaced by one 102-bp intron. Promoter regulatory eleme nts such as two "CAAT" boxes and one "TATA" box were identified. Several ci s-regulatory elements were recognized: stress-responsive elements (Myb-resp onsive elements) as well as G, H, and GC boxes. Moreover, elicitor-responsi ve elements (W boxes) and a sequence resembling the simian virus 40 enhance r core were found. In phloem and needles of control trees, the transcripts of stilbene synthase (STS) and PMT were hardly detectable. Increased ozone fumigation up to 0.3 muL L-1 enhanced the transcript level of STS and PMT i n needles but not in healthy phloem. Wounding, e.g. mock inoculation, of st em-phloem was characterized by a transient increase in STS and PMT transcri pts, which was more pronounced in the case of fungal inoculation. Combinati on of fungal-challenge or mock treatment with ozone resulted in a positive interaction at 0.3 muL L-1. Scots pine stilbene formation appeared to be in duced via STS and PMT gene expression upon ozone and fungal stress as well as wounding. The broad stress-responsiveness is in agreement with the range of various cis-acting elements detected in the STS and PMT promoters.