Lu, QiangShao, FenjuanMacmillan, ColleenWilson, Iain W.Van der Merwe, KarenHussey, Steven GrantMyburg, Alexander AndrewDong, XiaomeiQiu, Deyou2018-04-112018-04-112018-01Lu, Q., Shao, F.J., Macmillan, C. et al. 2018, 'Genomewide analysis of the lateral organ boundaries domain gene family in Eucalyptus grandis reveals members that differentially impact secondary growth', Plant Biotechnology Journal, vol. 16, pp. 124-136.1467-7644 (print)1467-7652 (online)10.1111/pbi.12754http://hdl.handle.net/2263/64506Figure S1 Conserved domains of EgLBD protein family.Figure S2 The chromosomal localization of the LBD gene family in Eucalyptus grandis.Figure S3 Subcellular localization of EgLBD22, EgLBD29 and EgLBD37 proteins.Figure S4 Gel electrophoresis analysis for the presence of the transgene in EgLBD22-oe, EgLBD29-oe and EgLBD37-oe plants.Figure S5 Validation for the expression of the transgene in EgLBD22-oe, EgLBD29-oe and EgLBD37-oe plants by qRT-PCR.Table S1 All the primers used in this study.Table S2 The coding sequences of LBD genes in Eucalyptus grandis.Table S3 The information of LBD gene family in Eucalyptus grandis.Table S4 Conserved motifs predicted by MEME program in EgLBD proteins.Table S5 Protein-protein interaction prediction for possible functional protein association networks of EgLBD22.Table S6 Protein-protein interaction prediction for possible functional protein association networks of EgLBD29.Table S7 Protein-protein interaction prediction for possible functional protein association networks of EgLBD37.Table S8 The differentially expressed genes between EgLBD22-oe and WT-84k plants.Table S9 The differentially expressed genes between EgLBD29-oe and WT-84k plants.Table S10 The differentially expressed genes between EgLBD37-oe and WT-84k plants.Table S11 The information of eight key differentially expressed genes in EgLBD22-oe, EgLBD29-oe and EgLBD37-oe plants.Lateral Organ Boundaries Domain (LBD) proteins are plant-specific transcription factors playing crucial roles in growth and development. However, the function of LBD proteins in Eucalyptus grandis remains largely unexplored. In this study, LBD genes in E. grandis were identified and characterized using bioinformatics approaches. Gene expression patterns in various tissues and the transcriptional responses of EgLBDs to exogenous hormones were determined by qRT-PCR. Functions of the selected EgLBDs were studied by ectopically overexpressing in a hybrid poplar (Populus alba 9 Populus glandulosa). Expression levels of genes in the transgenic plants were investigated by RNA-seq. Our results showed that there were forty-six EgLBD members in the E. grandis genome and three EgLBDs displayed xylem- (EgLBD29) or phloem-preferential expression (EgLBD22 and EgLBD37). Confocal microscopy indicated that EgLBD22, EgLBD29 and EgLBD37 were localized to the nucleus. Furthermore, we found that EgLBD22, EgLBD29 and EgLBD37 were responsive to the treatments of indol- 3-acetic acid and gibberellic acid. More importantly, we demonstrated EgLBDs exerted different influences on secondary growth. Namely, 35S::EgLBD37 led to significantly increased secondary xylem, 35S::EgLBD29 led to greatly increased phloem fibre production, and 35S:: EgLBD22 showed no obvious effects. We revealed that key genes related to gibberellin, ethylene and auxin signalling pathway as well as cell expansion were significantly up- or down-regulated in transgenic plants. Our new findings suggest that LBD genes in E. grandis play important roles in secondary growth. This provides new mechanisms to increase wood or fibre production.en© 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.Eucalyptus grandisGene expressionSecondary growthXylem developmentFibre productionStemProteinsIdentificationEvolutionExpression analysisRoot formationArabidopsis thalianaRNA-seq dataLateral organ boundaries domain (LBD)Article