Our results imply that ICR1 is part of an auxin regulated positive feedback loop realized by a unique integration of auxin-dependent transcriptional regulation into ROP-mediated modulation of cell polarity. Thus, ICR1 forms an auxin-modulated link between cell polarity, exocytosis, and auxin transport-dependent tissue patterning.

—Hazak et al.

Auxin is considered the most important plant hormone for plant growth and root growth. Prof. Yalovsky explains that knowing how to manipulate it can lead to much bigger yields of non-food crops, such as those needed for biofuel. Efficiency is now a limiting factor in biofuel production, and scientists are looking for anything that can produce biofuel in the same amounts as the production of traditional fossil-based fuels.

When the ICR1 protein is genetically engineered into valuable biofuel crops such as corn, sugarcane or experimentals like switchgrass, farmers can expect to get a far larger yield than what they harvest today, Prof. Yalovsky has found.

We’ve found a mechanism that helps the shoot and root talk to each other. Somehow both parts of the plant need to speak to each other to say: “Hey down there, I’m up here and there’s lots of sun,” or “I’m down here in the roots and it’s too dry.” The plant’s shoots need to respond to its environment. We’ve discovered the mechanism that helps auxin do its job.

—Prof. Yalovsky

The ICR1 protein that Prof. Yalovsky has isolated works together with a group of proteins called ROPs, which his lab also isolated in previous research. Together, this system of proteins work in harmony to manipulate the composition and vascular tissues of plant cell walls. The researchers found specifically that ICR1 can be manipulated and, as a consequence, influence auxin distribution in plants. Plant scientists now have a tool that allows breeders to grow certain plant organs of choice, with the possibility of manipulating plant cell wall composition—the kinds of tissues needed in making biofuel.

In the PLoS Biology report published recently, the researchers detail the links between the mechanisms that regulate cell structure and the development of the whole plant. The new system found in proteins and developed at Tel Aviv University has the potential to increase crop yield and make fuel production more cost-effective. His approach could mean less lignin, more cellulose and ultimately more biofuel, says Prof. Yalovsky.

Resources

• Hazak O, Bloch D, Poraty L, Sternberg H, Zhang J, et al. (2010) A Rho Scaffold Integrates the Secretory System with Feedback Mechanisms in Regulation of Auxin Distribution. PLoS Biol 8(1): e1000282. doi: 10.1371/journal.pbio.1000282