On the Edge 112 www.seed.ab.ca | Advancing Seed in Alberta Millet Genome Sequenced A study coordinated by an international consortium of French, Indian and Chinese researchers has enabled the genome sequence for millet to be obtained for the first time. This discovery improves the understanding of the organization and evolution of the genome of this cereal, which provide food security throughout the world. It also provides new prospects for selecting or improving varieties of millet that may be better equipped to cope with climate change. This research enabled the team to trace the origin of millet domestication, found to have taken place almost 4,500 years ago at the border between Mali and Niger. It highlighted genes that slow down the loss of water from the leaves (thus conserving hydration), as well as other genes related to withstanding dry conditions. Shining a Light on Plant Growth and Development Plants don’t have eyes, but they do “see” their surroundings using light. That’s made possible by proteins called photoreceptors that absorb light and convert it into a signal that turns genes on or off. Until now, scientists haven’t fully understood the molecular mechanism underlying that process, which allows plants to recognize when they’re in the shade and grow toward the sun, and to sense what season it is so they can bloom in spring. Researchers at the University of California, Riverside have identified the portion of a plant photoreceptor responsible for light-dependent changes in gene expression. Associate professor of cell biology Meng Chen and his colleagues have been studying a group of photoreceptors called phytochromes that are sensitive to red and far-red light, and are conserved in plants, fungi and bacteria. The research was done in Arabidopsis thaliana, a small flowering plant that is widely used by biologists as a model species because it is easy to grow and study. Phytochromes control plant growth and development by changing the amount or stability of another group of proteins called transcription factors whose job is to turn genes on and off. To find out how the photoreceptor regulates the amount of transcription factors, Chen’s team turned their attention to the structure of the phytochrome, which has two functional areas called domains. While it is known that one domain (called the N-terminal module) senses light, the function of the other domain (called the C-terminal module) had remained unknown. Chen’s group showed that the C-terminal module does in fact regulate gene expression, though it uses a very different method to bacteria. Chen said the findings have implications in agriculture, where farmers are increasingly looking to grow more food on less land. For example, when crops are planted at high density, they compete for light, often growing taller at the expense of yield. “Now that we understand how light is causing changes in growth and development, we can engineer plants to be blind to their neighbours, so we can plant them more densely without seeing a decrease in yield,” Chen said. “We can take crops that grow well in one part of the world and engineer them to grow in other latitudes and climates.” Wheat Gets Boost From Purified Nanotubes The introduction of purified carbon nanotubes appears to have a beneficial effect on the early growth of wheatgrass, according to Rice University scientists. But in the presence of contaminants, those same nanotubes could do great harm. The Rice lab of chemist Andrew Barron grew wheatgrass in a hydroponic garden to test the potential toxicity of nanoparticles on the plant. To their surprise, they found one type of particle dispersed in water helped the plant grow bigger and faster. They suspect the results spring from nanotubes’ natural hydrophobic (water-avoiding) nature that in one experiment apparently facilitated the plants’ enhanced uptake of water. The lab mounted the small-scale study with the knowledge that the industrial production of nanotubes will inevitably lead to their wider dispersal in the environment. The study cited rapid growth in the market for nanoparticles in drugs, cosmetic, fabrics, water filters and military weapons, with thousands of tons produced annually.