Open AccessGene regulatory networks for lignin biosynthesis in switchgrass (Panicum virgatum )
Author(s) -
Rao Xiaolan,
Chen Xin,
Shen Hui,
Ma Qin,
Li Guifen,
Tang Yuhong,
Pena Maria,
York William,
Frazier Taylor P.,
Lenaghan Scott,
Xiao Xirong,
Chen Fang,
Dixon Richard A.
Publication year - 2019
Publication title -
plant biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.525
H-Index - 115
eISSN - 1467-7652
pISSN - 1467-7644
DOI - 10.1111/pbi.13000
Subject(s) - panicum virgatum , lignin , biology , secondary cell wall , transcription factor , gene regulatory network , cell wall , gene , microbiology and biotechnology , botany , gene expression , biofuel , biochemistry , bioenergy
Summary Cell wall recalcitrance is the major challenge to improving saccharification efficiency in converting lignocellulose into biofuels. However, information regarding the transcriptional regulation of secondary cell wall biogenesis remains poor in switchgrass ( Panicum virgatum ), which has been selected as a biofuel crop in the United States. In this study, we present a combination of computational and experimental approaches to develop gene regulatory networks for lignin formation in switchgrass. To screen transcription factors ( TF s) involved in lignin biosynthesis, we developed a modified method to perform co‐expression network analysis using 14 lignin biosynthesis genes as bait (target) genes. The switchgrass lignin co‐expression network was further extended by adding 14 TF s identified in this study, and seven TF s identified in previous studies, as bait genes. Six TF s (Pv MYB 58/63, Pv MYB 42/85, Pv MYB 4, Pv WRKY 12, Pv SND 2 and Pv SWN 2) were targeted to generate overexpressing and/or down‐regulated transgenic switchgrass lines. The alteration of lignin content, cell wall composition and/or plant growth in the transgenic plants supported the role of the TF s in controlling secondary wall formation. RNA ‐seq analysis of four of the transgenic switchgrass lines revealed downstream target genes of the secondary wall‐related TF s and crosstalk with other biological pathways. In vitro transactivation assays further confirmed the regulation of specific lignin pathway genes by four of the TF s. Our meta‐analysis provides a hierarchical network of TF s and their potential target genes for future manipulation of secondary cell wall formation for lignin modification in switchgrass.