cDNA macroarray analysis of genes expressed in plumules of Pharbitis nil after induction of flowering

SUMMARYA cDNA library was constructed from mRNA extracted from plumules including shoot apical meristems, 24 h after a 16 h dark treatment, to clone genes preferentially expressed during flower evocation in a short-day plant, Pharbitis nil. We partially sequenced 768 randomly selected cDNAs. A database search for these expressed sequence tags (ESTs) revealed that 57.4% were similar to registered genes and the remaining 42.6% showed no significant similarity to known genes. By using a cDNA macroarray, cDNAs derived from the plumules of P. nil subjected to one short-day (SD) to induce flowering, or kept under long-day (LD) conditions as a control, were hybridised with these EST clones. Six of the 768 clones were preferentially expressed by the SD treatment. Three of these were clones similar to chlorophyll a/b binding protein 8 (CAB-8), ubiquitin and a 60 kDa chaperonin -subunit gene. The other three clones did not show similarity to any known genes. The preferential expression of these genes by SD treatment suggests possible roles in flower evocation in the shoot apical meristem.