Hairpin Turn: Micro-RNA Plays Role in Wood Formation

For more than a decade, scientists have suspected that hairpin-shaped chains of micro-RNA regulate wood formation inside plant cells. Now, scientists at NC State University have found the first example and mapped out key relationships that control the process.

The research describes how one strand of micro-RNA reduced by more than 20 percent the formation of lignin, which gives wood its strength. Understanding how to reduce lignin at the cellular level could lead to advances in paper and biofuels production, where harsh chemicals and costly treatments are used to remove lignin from wood.

"This is the first time that we have proof that a micro-RNA controls lignin biosynthesis," said Dr. Vincent Chiang, who co-directs NC State's Forest Biotechnology Group. Through five years of "very detailed analysis," the team confirmed that micro-RNA acts as a master regulator in reducing formation of lignin in transgenic black cottonwood, Chiang said.

Researchers used mathematical analysis to map out a three-layered network of relationships among key transcription factors and the micro-RNA that controls expression of laccase genes as well as other peroxidase genes involved in wood formation.