Ptr-miR397a is a negative regulator of laccase genes affecting lignin content in Populus trichocarpa

• DOI: 10.1073/pnas.1308936110
• Publication Date: 2013-06-11T04:02:47Z
• Authors: Shanfa Lu; Quanzi Li; Hairong Wei; Mao-Ju Chang; Sermsawat Tunlaya...; Hoon Kim; Jie Liu; Jingyuan Song; Ying-Hsuan Sun; Lichai Yuan; Ting-Feng Yeh; Ilona Peszlen; John Ralph; Ronald R. Sederoff; Vincent L. Chiang
• Keywords: Populus trichocarpa; Monolignol

Laccases, as early 1959, were proposed to catalyze the oxidative polymerization of monolignols. Genetic evidence in support this hypothesis has been elusive due functional redundancy laccase genes. An Arabidopsis double mutant demonstrated involvement laccases lignin biosynthesis. We previously identified a subset genes be targets microRNA (miRNA) ptr-miR397a Populus trichocarpa . To elucidate roles and its targets, we characterized gene family 49 models, which 29 predicted ptr-miR397a. overexpressed Ptr-MIR397a transgenic P. In each all nine lines tested, 17 PtrLAC s down-regulated analyzed by RNA-seq. Transgenic with severe reduction expression these resulted an ∼40% decrease total activity. Overexpression also reduced content, whereas levels monolignol biosynthetic transcripts remained unchanged. A hierarchical genetic regulatory network (GRN) built bottom-up graphic Gaussian model algorithm provides additional for role negative regulator Full transcriptome–based differential transgenics protein domain analyses implicate unidentified transcription factors their extended GRN including that coregulate biosynthesis wood formation. Ptr-miR397a, laccases, other components may provide strategies manipulation content.