Review: Plant Polyamines for Growth and Survival

Polyamines are organic compounds that are involved in diverse processes in cells, such as regulation of gene expression and cell proliferation, modulation of cell signaling and stabilization of membranes. They are also important regulators of ion channels and molecule transporters in the cell membrane. Being positively charged, polyamines can bind to macromolecules such as DNA, RNA and proteins. Scientists have identified the genes necessary for polyamine biosynthesis in plants, and mutation studies confirmed their importance in plant growth and development. An article published by the journal Planta summarizes the recent discoveries in polyamine research in plant science compared to what is known in microbial and animal systems.

Plant polyamines frequently accumulate in response to biotic and abiotic stresses. It was discovered that exogenously applied polyamines protect the plants from stress. Drought-tolerant rice and sweet potato over-expressing polyamine biosynthetic genes have been developed in laboratories. Polyamines, specifically spermine, also play defensive roles during stress by eliciting cell death at the sight of pathogen entry.

The authors noted however, that knowledge on plant polyamines is still behind compared to animal and microbial systems. For instance the molecules involved in transporting polyamines in and out of the cell remain unknown.

The paper, authored by scientists from Tohoku University in Japan, is available at http://www.springerlink.com/content/092243075686380j/fulltext.pdf