A tale of dwarfs and drugs: brassinosteroids to the rescue

Brassinosteroids (BRs), a specific class of low abundance plant steroids, a re capable of eliciting strong growth responses and a variety of physiologi cal changes through exogenous application to plants. Recently, BRs gained g eneral acceptance ns important regulators (hormones) of plant growth and de velopment through genetic and molecular identification and characterization of genes involved in BR biosynthesis or response in Arabidopsis, pen and t omato. This major advance in the molecular genetics of BR biosynthesis ann mode of action disclosed another case of amazing functional conservation of signalling molecules utilized in plants and animals, and provided a set of extremely valuable tools for the functional analysis of BRs.