Leaves guide plant's battle for sunlight

Washington, April 16 (IANS) A plant's primary weapon for survival is the ability to grow towards the light, getting just the amount it needs and shadowing its competition, says a study.

Now, scientists at the Salk Institute for Biological Studies have determined precisely how leaves tell stems to grow when a plant is caught in a shady place.

The findings may offer new ways of developing crops which would produce higher yields of foods and biofuels than existing strains, said Joanne Chory, professor and director at the Salk's Plant Biology Lab, who led the study.

A protein known as phytochrome interacting factor 7 (PIF7) serves as the key messenger between a plant's cellular light sensors and the production of auxins, hormones that stimulate stem growth, the journal Genes and Development reported.

"Now that we know PIF7 is the relay, we have a new tool to develop crops that optimize field space and thus produce more food or feedstock for biofuels and bio-renewable chemicals," said Chory, according to a university statement.

Plants gather intelligence about their light situation -- including whether they are surrounded by other light-thieving plants -- through photosensitive molecules in their leaves.

These sensors determine whether a plant is in full sunlight or in the shade of other plants, based on the wavelength of red light striking the leaves.

If a sun-loving plant, such as thale cress (Arabidopsis thaliana), the species Chory studies, finds itself in a shady place, the sensors will tell cells in the stem to elongate, causing the plant to grow upwards towards sunlight.