Isolation of a PSTAIRE CDC2 cDNA from Pinus contorta and its expression during adventitious root development

A CDC2 cDNA, PcCDC2, whose deduced amino acid sequence contains the conserv ed motifs characteristic of the PSTAIRE class of cyclin-dependent kinase ha s been isolated from Pinus contorta. The gymnosperm CDC2s are very similar and group together in a phylogenetic comparison, but the presence of a larg e gene family in Picea is not present in Pinus. During auxin-induced advent itious root development, the steady-state transcript levels of PcCDC2 show a linear increase the first 12 d after treatment. In untreated hypocotyl cu ttings, the level of PcCDC2 expression is equal to the level of expression in roots and shoots harbouring meristems of high proliferation activity. Th e expression of PcCDC2 during adventitious root development does not coinci de with histone H2A expression, a S-phase correlated marker. Therefore, the expression of PcCDC2 in hypocotyls suggests a state of competence in which the appropriate cells are capable of responding to auxin for adventitious root development. (C) 2001 Editions scientifiques et medicales Elsevier SAS .