The nightshade proteinase inhibitor IIb gene is constitutively expressed in glandular trichomes. Plant Cell Physiol

The best known property of plant proteinase inhibitor II (PIN2) genes is their wound-inducible expression in leaves and constitutive expression in flowers. Here we show by promoter analysis in transgenic plants and in situ reverse transcription–PCR (RT–PCR) analysis that SaPIN2b, a member of the PIN2 gene family of nightshade (Solanum americanum), is also constitutively expressed in glandular trichomes. SaPIN2b promoter and its deletions were cloned and fused upstream of b-glucuronidase (GUS) to transform the nightshade and tobacco (Nicotiana tabacum) plants. Histochemical staining assays indicated that SaPIN2b:GUS was expressed constitutively in glandular trichomes, predom-inantly in the gland cells, of both transgenic nightshade and tobacco plants. Constitutive expression of SaPIN2b in glandular trichomes was further confirmed by liquid phas