Media Releases

Time of day matters to thirsty trees, U of T researchers discover

November 23, 2009

TORONTO, ON — The time of day mat­ters to for­est trees deal­ing with drought, accord­ing to a new paper pro­duced by a research team led by Pro­fes­sor Mal­colm Camp­bell, Uni­ver­si­ty of Toron­to Scar­bor­ough’s vice-prin­ci­pal for research and col­leagues in the depart­ment of cell and sys­tems biol­o­gy at the St. George cam­pus.

Cap­i­tal­iz­ing on their pre­vi­ous work to decode the genome of the poplar tree, the research team exam­ined how poplar trees use their 45,000 genes to respond to drought. Camp­bell and PhD stu­dent Olivia Wilkins, the lead researchers, along with researchers Levi Wal­dron, Hard­eep Nahal and Nicholas Provart, had their find­ings pub­lished in the Novem­ber 13 issue of The Plant Jour­nal. The arti­cle is titled “Geno­type and time of day shape the Pop­u­lus drought response.”

“Each gene is like a line of code in a com­put­er pro­gram” says Camp­bell, a plant biol­o­gist. “Depend­ing on which lines of code are used, the tree can cre­ate a dif­fer­ent pro­gram to respond to envi­ron­men­tal stim­uli, like drought.” The use of dif­fer­ent com­bi­na­tions of genes cre­ates dif­fer­ent pro­grams. The com­bi­na­tion of genes that trees use in response to a stress, like drought, deter­mines whether the tree can sur­vive this stress or not.

In the past, researchers exam­ined drought-respon­sive gene pro­grams at a sin­gle time point — nor­mal­ly in the mid­dle of the day when most researchers work in the lab or the field. Wilkins did her exper­i­ments so that she exam­ined the gene pro­grams at mul­ti­ple times through­out the day and night.

Sur­pris­ing­ly, work­ing togeth­er with Uni­ver­si­ty of Toron­to bioin­for­mati­cians, the team found that trees used dif­fer­ent drought response gene pro­grams at dif­fer­ent times of day. That is, the drought response gene pro­gram that the trees used in the mid­dle of the day was dif­fer­ent from the pro­gram used in the mid­dle of the night.

“Pre­vi­ous­ly, researchers referred to the drought response as though it was a sin­gle, sim­ple pro­gram that ran all the time,” Camp­bell notes. The new research shows that the sto­ry is not that sim­ple. “Rather than one pro­gram, trees use mul­ti­ple pro­grams, each of which runs at a dif­fer­ent time of day,” says Wilkins.

The dis­cov­ery that trees use dif­fer­ent pro­grams at dif­fer­ent times of the day is described as a crit­i­cal find­ing. Pre­vi­ous research may have overem­pha­sised the impor­tance of some genes in help­ing trees to con­tend with drought, and total­ly missed oth­ers that are impor­tant.

The new work pro­vides insights and tools to enable future researchers to iden­ti­fy, con­serve and breed trees that are bet­ter able to con­tend with drought. Drought is an increas­ing­ly-impor­tant mal­a­dy for for­est trees, as it can dra­mat­i­cal­ly reduce for­est growth, and, in severe cas­es, increase for­est sus­cep­ti­bil­i­ty to insect pests and bring about cat­a­stroph­ic for­est death. Giv­en the impor­tance of for­est trees in vast ecosys­tems the world over, and as a renew­able resource of great eco­nom­ic val­ue, a bet­ter under­stand­ing of how trees con­tend with drought can have far-reach­ing impli­ca­tions for the envi­ron­ment and the econ­o­my. The new find­ings could play a role in safe­guard­ing one of Canada’s most impor­tant nat­ur­al resources, our for­est trees.

This new Uni­ver­si­ty of Toron­to research was sup­port­ed by the Nat­ur­al Sci­ences and Engi­neer­ing Research Coun­cil of Cana­da and is pub­lished in one of the top-ranked plant research jour­nals, The Plant Jour­nal. To view the paper online, vis­it:


For more infor­ma­tion, please con­tact:

Eleni Kanavas
Media Coor­di­na­tor
Uni­ver­si­ty of Toron­to Scar­bor­ough