Biological clock of plants is sensitive to nutrient status

Washington, March 16 : An international team of researchers ave identified that the master gene controlling the biological lock in plants is sensitive to nutrient status.

The study was conducted by a team of researchers at New York niversity's Center for Genomics and Systems Biology, Chile's ontificia Universidad Catslica de Chile, Dartmouth College, and old Spring Harbor Labs.

For the study, the researchers took the case of the plant rabidopsis.

Using a systems biological analysis of genome-scale data from rabidopsis, the researchers identified that the master gene ontrolling its biological clock is sensitive to nutrient status.

This hypothesis derived from multi-network analysis of rabidopsis genomic data, and validated experimentally, has shed ight on how nutrients affect the molecular networks controlling lant growth and development in response to nutrient sensing.

According to Rodrigo A. Gutiirrez and Gloria Coruzzi, the study's ead authors, the systems biology approach to uncovering nutrient egulated gene networks provides new targets for engineering raits in plants of agronomic interest such as increased nitrogen se efficiency, which could lead to reduced fertilizer cost and owering ground water contamination by nitrates.

Nitrogen is an essential nutrient and a metabolic signal that is ensed and converted, resulting in the control of gene expression n plants. In addition, nitrate has been shown to serve as a ignal for the control of gene expression in Arabidopsis, the irst flowering plant to have its entire genome sequenced.

There is existing evidence, on a gene-by-gene basis, that roducts of nitrogen assimilation, the amino acids glutamate Glu) or glutamine (Gln), might serve as signals of organic itrogen status that are sensed and in turn regulate gene xpression.

To identify genome-wide responses to such organic nitrogen ignals, the researchers treated Arabidopsis seedlings with norganic nitrogen (N) in both the presence and the absence of hemicals that inhibit the assimilation into organic N and onducted a genome-wide analysis of all genes whose expression esponds to inorganic or organic forms of nitrogen.

Using an integrated network model of molecular interactions for rabidopsis - constructed by the researchers - in which pproximately 7,000 genes are connected by 230,000 molecular nteractions, they uncovered a sub-network of genes regulated by rganic nitrogen that includes a highly connected network "hub" CA1, which controls a plant's biological clock, and target genes nvolved in nitrogen assimilation.

The findings thus provide evidence that plant nutrition, like nimal nutrition, is tightly linked to circadian, or biological lock, functions as scientists have previously hypothesized.

This study indicates that nitrogen nutrition affects CCA1, the entral clock gene of plants, suggesting nutritional regulation f the biological clock occurs in plants.

ANI