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Xylem vessel‐specific SND5 and its homologs regulate secondary wall biosynthesis through activating secondary wall NAC binding elements
Author(s) -
Zhong Ruiqin,
Lee Chanhui,
Haghighat Marziyeh,
Ye ZhengHua
Publication year - 2021
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.17425
Subject(s) - secondary cell wall , xylem , secondary metabolism , cell wall , transcription factor , gene , microbiology and biotechnology , protein secondary structure , biosynthesis , secondary growth , arabidopsis , biology , arabidopsis thaliana , ectopic expression , chemistry , biochemistry , botany , mutant
Summary Secondary cell wall biosynthesis has been shown to be regulated by a suite of transcription factors. Here, we identified a new xylem vessel‐specific NAC domain transcription factor, secondary wall‐associated NAC domain protein5 (SND5), in Arabidopsis thaliana and studied its role in regulating secondary wall biosynthesis. We showed that the expression of SND5 and its close homolog, SND4/ANAC075 , was specifically associated with secondary wall‐containing cells and dominant repression of their functions severely reduced secondary wall thickening in these cells. Overexpression of SND4/5 as well as their homologs SND2/3 fused with the activation domain of the viral protein VP16 led to ectopic secondary wall deposition in cells that are normally parenchymatous. SND2/3/4/5 regulated the expression of the same downstream target genes as do the secondary wall NAC master switches (SWNs) by binding to and activating the secondary wall NAC binding elements (SNBEs). Furthermore, we demonstrated that the poplar ( Populus trichocarpa ) orthologs of SND2/3/4/5 also activated SNBEs and regulated secondary wall biosynthesis during wood formation. Together, these findings indicate that SND2/3/4/5 and their poplar orthologs regulate the expression of secondary wall‐associated genes through activating SNBEs and they are positioned at an upper level in the SWN‐mediated transcriptional network.