A team of scientists from Japan, Europe, and theUSAhas identified a
pathway leading to accelerated flowering of plants in low-nitrogen
soils. The scientists, led by Associate Professor Takeo Sato of Hokkaido
University's Graduate School of Life Science, have revealed the
molecular mechanism responsible for the acceleration of flowering in
Arabidopsis under low nitrogenconditions.

The research team identified a set of proteins involved in flowering
that became active as a result of changes in nitrogen level. One of
these was the gene regulation factor FLOWERING BHLH 4 (FBH4). Through
experiments using FBH4 deficient plants, this protein was found to be
responsible for accelerated flowering under low-nitrogen conditions.

Further research suggests that FBH4 is extensively phosphorylated by
another protein called SnRK1. Low-nitrogen conditions suppress SnRK1
activity, which in turn results in the dephosphorylation of FBH4. The
dephosphorylated FBH4 moves to the nucleus to activate genes responsible
for flowering. Dephosphorylated FBH4 is also responsible for controlling
the expression of other genes vital for plant survival under low
nitrogen conditions, particularly those related to nitrogen recycling
and remobilization.

Plant flowering in low-nitrogen soils: a mechanism revealed | Hokkaido
University (hokudai.ac.jp)
[www.global.hokudai.ac.jp]