Figure: Takeo Sato, with Arabidopsis plants in the culture room. Photo Source: Takeo Sato.

A team of scientists from Japan, Europe, and the USA has 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 nitrogen conditions.

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.

For more details, read the research press release from Hokkaido University.