Transcripts for a lectin-like gene accumulate in the epidermis but not the protodermis of the pea shoot apex

Abstract

We describe a novel pattern of tissue- and position-dependent accumulation for transcripts encoding a lectin-like protein (Blec) in pea (Pisum sativum L.). This pattern indicates a regulatory difference between the protodermis of the apical meristem and the derived epidermal cells of surrounding shoot apex: BlecRNA is absent or present at very low levels in protodermal cells of the apical meristem but is highly expressed in the derived epidermal cells of leaf primordia flanking the apical meristem. A similar pattern is seen during floral development: transcripts are undetectable in the protodermis of the floral dome and floral organ primordia, but are first detected during organ formation and expansion. This finding supports the hypothesis that the apical meristem functions as a unit distinct from the surrounding shoot apex.