Micro-RNA plays role in wood formation June 10, 2013 - 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, published online in Proceedings of the National Academy of Sciences the week of June 10, 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 with Dr. Ron Sederoff, a member of the National Academy of Sciences. 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. The network illustrates the hierarchy of gene control and narrows the transcription factors of interest from approximately 2,000 to 20. "That's still a career's worth of research," Chiang said. Lead authors are Dr. Shanfa Lu, former NC State postdoctoral scientist and now professor with the Chinese Academy of Medical Sciences and Peking Union Medical College, and Dr. Quanzi Li, senior research associate with NC State's Forest Biotechnology Group. Dr. Hairong Wei, professor of systems and computational biology at Michigan Technological University, created a unique algorithm for mapping the genetic regulatory network. The research was funded with a National Science Foundation Plant Genome Research Program Grant (DBI-0922391).