title: Genome-wide analysis of the TPX2 family proteins in Eucalyptus grandis.
abstract: The Xklp2 (TPX2) proteins belong to the microtubule-associated (MAP) family of proteins. All members of the family contain the conserved TPX2 motif, which can interact with microtubules, regulate microtubule dynamics or assist with different microtubule functions, for example, maintenance of cell morphology or regulation of cell growth and development. However, the role of members of the TPX family have not been studied in the model tree species Eucalyptus to date. Here, we report the identification of the members of the TPX2 family in Eucalyptus grandis (Eg) and analyse the expression patterns and functions of these genes.
  
  
  
  In present study, a comprehensive analysis of the plant TPX2 family proteins was performed. Phylogenetic analyses indicated that the genes can be classified into 6 distinct subfamilies. A genome-wide survey identified 12 members of the TPX2 family in the sequenced genome of Eucalyptus grandis. The basic genetic properties of the TPX2 family in Eucalyptus were analysed. Our results suggest that the TPX2 family proteins within different sub-groups are relatively conserved but there are important differences between groups. Quantitative real-time PCR (qRT-PCR) was performed to confirm the expression levels of the genes in different tissues. The results showed that in the whole plant, the levels of EgWDL5 transcript are the highest, followed by those of EgWDL4. Compared with other tissues, the level of the EgMAP20 transcript is the highest in the root. Over-expression of EgMAP20 in Arabidopsis resulted in organ twisting. The cotyledon petioles showed left-handed twisting while the hypocotyl epidermal cells produced right-handed helical twisting. Finally, EgMAP20, EgWDL3 and EgWDL3L were all able to decorate microtubules.
  
  
  
  Plant TPX2 family proteins were systematically analysed using bioinformatics methods. There are 12 TPX2 family proteins in Eucalyptus. We have performed an initial characterization of the functions of several members of the TPX2 family. We found that the gene products are localized to the microtubule cytoskeleton. Our results lay the foundation for future efforts to reveal the biological significance of TPX2 family proteins in Eucalyptus.
authors.affiliation: State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642, China.|Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, 510642, China.|College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China.|Provincial Key Laboratory of Agrobiology, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China.
authors.forename: Pingzhou
authors.initials: P
authors.lastname: Du
authors.affiliation: Faculty of Life Science, University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK.
authors.forename: Manoj
authors.initials: M
authors.lastname: Kumar
authors.affiliation: State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642, China.|Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, 510642, China.|College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Yao
authors.affiliation: State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642, China.|Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, 510642, China.
authors.forename: Qiaoli
authors.initials: Q
authors.lastname: Xie
authors.affiliation: Provincial Key Laboratory of Agrobiology, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China.
authors.forename: Jinyan
authors.initials: J
authors.lastname: Wang
authors.affiliation: Provincial Key Laboratory of Agrobiology, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China.
authors.forename: Baolong
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Research Institute of tropical forestry, Chinese Academy of Forestry, Guangzhou, 510520, China. siming_gan@126.com.
authors.forename: Siming
authors.initials: S
authors.lastname: Gan
authors.affiliation: College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China. wyq@scau.edu.cn.|Boyce Thompson Institute for Plant Research, Ithaca, 14853, USA. wyq@scau.edu.cn.
authors.forename: Yuqi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642, China. wuaimin@scau.edu.cn.|Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, 510642, China. wuaimin@scau.edu.cn.
authors.forename: Ai-Min
authors.initials: AM
authors.lastname: Wu
mesh_terms: D020816:Amino Acid Motifs; D019295:Computational Biology / Q000379:methods; D005052:Eucalyptus / Q000235:genetics* / Q000378:metabolism; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D018745:Genome, Plant; D055106:Genome-Wide Association Study; D008869:Microtubule-Associated Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005810:Multigene Family; D010641:Phenotype; D010802:Phylogeny; D030821:Plants, Genetically Modified; D054730:Protein Interaction Domains and Motifs; D021381:Protein Transport; D017422:Sequence Analysis, DNA
chemical_list: D008869:Microtubule-Associated Proteins
keywords: Eucalyptus; Expression profiling; Organ twisting; Phylogenetic analysis; Subcellular localization; TPX2 family proteins