Over-expression of poplar NAC15 gene enhances wood formation in transgenic tobacco

Wenjing Yao,Tingbo Jiang,Dawei Zhang,Boru Zhou,Jianping Wang,Renhua Li

doi:10.1186/s12870-019-2191-2

Wenjing Yao, Tingbo Jiang + Show 4 more

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https://doi.org/10.1186/s12870-019-2191-2

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Abstract

BackgroundNAC (NAM/ATAF/CUC) is one of the largest plant-specific transcription factor (TF) families known to play significant roles in wood formation. Acting as master gene regulators, a few NAC genes can activate secondary wall biosynthesis during wood formation in woody plants.ResultsIn the present study, firstly, we screened 110 differentially expressed NAC genes in the leaves, stems, and roots of di-haploid Populus simonii×P. nigra by RNA-Seq. Then we identified a nucleus-targeted gene, NAC15 gene, which was one of the highly expressed genes in the stem among 110 NAC family members. Thirdly, we conducted expression pattern analysis of NAC15 gene, and observed NAC15 gene was most highly expressed in the xylem by RT-qPCR. Moreover, we transferred NAC15 gene into tobacco and obtained 12 transgenic lines overexpressing NAC15 gene (TLs). And the relative higher content of hemicellulose, cellulose and lignin was observed in the TLs compared to the control lines containing empty vector (CLs). It also showed darker staining in the culms of the TLs with phloroglucinol staining, compared to the CLs. Furthermore, the relative expression level of a few lignin- and cellulose-related genes was significantly higher in the TLs than that in the CLs.ConclusionsThe overall results indicated that NAC15 gene is highly expressed in the xylem of poplar and may be a potential candidate gene playing an important role in wood formation in transgenic tobacco.

Highlights

NAC (NAM/ATAF/CUC) is one of the largest plant-specific transcription factor (TF) families known to play significant roles in wood formation
A unique tissuespecific transcript analysis revealed that lignin and cellulose biosynthetic-related genes, transcription factors (TFs) and other potential regulators of xylogenesis were under strict developmental stage-specific transcriptional regulation in
We screened differentially expressed NAC genes in the leaves, stems, and roots of di-haploid Populus simonii×P. nigra by RNA-Seq

Summary

Introduction

NAC (NAM/ATAF/CUC) is one of the largest plant-specific transcription factor (TF) families known to play significant roles in wood formation. Acting as master gene regulators, a few NAC genes can activate secondary wall biosynthesis during wood formation in woody plants. There are mainly two kinds of cells with secondary cell walls in the process of wood formation, fibres and tracheary elements. The formation of the two types of cells goes through cell expansion, deposition of secondary walls, As a model tree, Populus is usually used to understand the unique processes that occur in woody plants, including wood formation [4, 5]. The molecular and genetic mechanisms regulating wood formation in Populus have been studied by developmental genetic, genomic and biochemical approaches [6]. The identification of expressed sequence tags (ESTs), hormones and genes regulating wood formation is getting popularity in Populus [7,8,9]. A unique tissuespecific transcript analysis revealed that lignin and cellulose biosynthetic-related genes, transcription factors (TFs) and other potential regulators of xylogenesis were under strict developmental stage-specific transcriptional regulation in

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