Tree timer

© Pekka Parviainen / Photo Researchers, Inc.

Ove Nilsson et al. "CO/FT regulatory module controls timing of flowering and seasonal growth cessation in trees," Science, 312:1040-3, 2006. (Cited in 58 papers).

While trying to speed up breeding in flowering trees, Ove Nilsson's group from the Swedish University of Agricultural Sciences discovered the same genes regulating flowering in annual plants - CONSTANS (CO) and FLOWERING LOCUS T (FT) - playing a similar role in aspen trees, by regulating growth and dormancy. Differences in the perennial seasonal transition between aspen trees originating from Northern and Southern hemispheres in Northern Europe could be explained by the phase of CO expression in daylight.

Researchers long knew trees from different geographical regions entered dormancy in response to different day lengths, but is was not clear how, says Antje Rohde, a plant geneticist from the Institute for Agricultural and Fisheries Research in Belgium, who was not involved in the study. The genes regulating photoperiod flowering in annual plants were never considered.

The study revealed new genes and pathways involved in the seasonal growth-dormancy of perennial trees, but the findings are being applied to other species as well: recent studies have found CO/FT controls short-day induced tuberization in potatoes, Nilsson said in an E-mail.

Nilsson's group is trying to find variations in gene activity to explain why aspens from different latitudes have different phases of CO expression and understand the similarities between regulation of flowering and growth cessation.