Gene expression in cambial zone of hybrid walnut stem related to radial growth.

摘要

Wood formation is a physiological continuum where cambial cells divide, elongate and differentiate into young xylem to constitute sapwood tissues and contribute to radial growth. The research is focused on cambial activity and our aim is to increasethe understanding of the making of walnut wood and to gain knowledge for the wood-chain industry. Here, we will only take into account xylem cells production which involves cell division and the beginning of cell elongation. Cell division is a final stage of cell cycle control which is active during interphase. Target genes involved in the control of cell cycle can be identified from published data. Amongst those genes, one coding for a cyclin-dependent kinase (cdc2a) has been isolated in hybrid walnutfor use as a molecular marker of cambial activity. A 597 bp sequence of cdc2a gene has been obtained through RT-PCR and its expression pattern during radial growth of hybrid walnut was studied. This paper reports the first results on the study of the relationship between radial growth and cdc2a purified mRNA levels for hybrid walnut during the growing season. Results show increasing levels of cdc2a mRNA in hybrid walnut concomitant to radial growth that suggests cdc2a could be a marker of cambial activity in hybrid walnut.