Large-scale transcriptional profiling of lignified tissues in Tectona grandis

BMC Plant Biology

Research Article

Maria Katherine Mejia-Guerra¹  Mabel Vidal¹  Helaine Carrer²  Esteban Galeano²  Tarcísio Sales Vasconcelos² 

[1] CAPS Computational Biology Laboratory (CCBL), Center for Applied Plant Sciences, Ohio State University, 206 Rightmire Hall, 1060 Carmack Road, 43210, Columbus, Ohio, United States;Laboratório de Biotecnologia Agrícola (CEBTEC), Departamento de Ciências Biológicas, Escola Superior de Agricultura “Luiz de Queiroz”, Universidade de São Paulo, Av. Pádua Dias, 11, 13418-900, Piracicaba, São Paulo, Brazil;

关键词: Lignin Biosynthesis;    Secondary Xylem;    Lignified Tissue;    Teak Tree;    Teak Wood;   

DOI  :  10.1186/s12870-015-0599-x

 received in 2014-12-12, accepted in 2015-09-02,  发布年份 2015

来源: Springer

【 摘 要 】

BackgroundCurrently, Tectona grandis is one of the most valuable trees in the world and no transcript dataset related to secondary xylem is available. Considering how important the secondary xylem and sapwood transition from young to mature trees is, little is known about the expression differences between those successional processes and which transcription factors could regulate lignin biosynthesis in this tropical tree. Although MYB transcription factors are one of the largest superfamilies in plants related to secondary metabolism, it has not yet been characterized in teak. These results will open new perspectives for studies of diversity, ecology, breeding and genomic programs aiming to understand deeply the biology of this species.ResultsWe present a widely expressed gene catalog for T. grandis using Illumina technology and the de novo assembly. A total of 462,260 transcripts were obtained, with 1,502 and 931 genes differentially expressed for stem and branch secondary xylem, respectively, during age transition. Analysis of stem and branch secondary xylem indicates substantial similarity in gene ontologies including carbohydrate enzymes, response to stress, protein binding, and allowed us to find transcription factors and heat-shock proteins differentially expressed. TgMYB1 displays a MYB domain and a predicted coiled-coil (CC) domain, while TgMYB2, TgMYB3 and TgMYB4 showed R2R3-MYB domain and grouped with MYBs from several gymnosperms and flowering plants. TgMYB1, TgMYB4 and TgCES presented higher expression in mature secondary xylem, in contrast with TgMYB2, TgHsp1, TgHsp2, TgHsp3, and TgBi whose expression is higher in young lignified tissues. TgMYB3 is expressed at lower level in secondary xylem.ConclusionsExpression patterns of MYB transcription factors and heat-shock proteins in lignified tissues are dissimilar when tree development was evaluated, obtaining more expression of TgMYB1 and TgMYB4 in lignified tissues of 60-year-old trees, and more expression in TgHsp1, TgHsp2, TgHsp3 and TgBi in stem secondary xylem of 12-year-old trees. We are opening a door for further functional characterization by reverse genetics and marker-assisted selection with those genes. Investigation of some of the key regulators of lignin biosynthesis in teak, however, could be a valuable step towards understanding how rigidity of teak wood and extractives content are different from most other woods. The obtained transcriptome data represents new sequences of T. grandis deposited in public databases, representing an unprecedented opportunity to discover several related-genes associated with secondary xylem such as transcription factors and stress-related genes in a tropical tree.

【 授权许可】

CC BY   
© Galeano et al. 2015