Research conducted by scientists at Earlham Institute and John Innes
Centre reveals the multiple ways in which thewheatcircadian clock
maintains balance. Published in/PLOS Biology/, this work is the first to
gauge the role of circadian rhythms across the entire genomeof polyploid
wheat.

The circadian clock is a finely balanced time-keeping mechanism that
guides organisms through day and night, as well as changes in seasons.
The accuracy of this clock affects a plant's health and productivity. In
model plants, the circadian clock controls genes that influence pest
resistance, water use, cold and heat tolerance, nitrogen efficiency, and
photosynthetic yields. The researchers wanted to see whether the same
was true in wheat.

Dr. Hannah Rees, the lead author of the study, said that understanding
how the circadian clock works in wheat is tricky because the wheat grown
today is the result of three wheat species merging into one. The
researchers generated a high-resolution dataset to investigate the
circadian balance between sets of three homoeologous genes- known as
triads - from the hexaploid bread wheat. Gene expression was mapped out
at regular intervals and under different light conditions to mimic the
rising and setting sun.

They found that around 30 percent of the genes in wheat were regulated
in some way by circadian rhythms, including genes responsible for
regulating photosynthesis, starch metabolism, heat and cold resistance,
and even marshaling biological defenses to attacks from plant pests. The
researchers also found widespread activity between competing genes and
said that circadian balance is not always necessarily a good thing.
While maintaining similar expression seems to be important for some sets
of genes, other sets appear to be given the freedom to experiment and
potentially do new things.

[www.earlham.ac.uk]