2022 journal article

p A PtrLBD39-mediated transcriptional network regulates tension wood formation in Populus trichocarpa


author keywords: tension wood; cellulose; lignin; transcriptional regulatory network; transcriptomics; chromatin immunoprecipitation sequencing
MeSH headings : Biomechanical Phenomena; Gene Expression Regulation, Plant / physiology; Gene Regulatory Networks / physiology; Genes, Plant / genetics; Genes, Plant / physiology; Laser Capture Microdissection; Populus / genetics; Populus / physiology; Wood / genetics; Wood / physiology; Xylem
TL;DR: This work suggests that P trLBD39 and PtrLBD22 specifically control TW formation by mediating a TW-specific TRN in Populus by directly regulating 26 novel TW-responsive transcription factor genes. (via Semantic Scholar)
Source: Web Of Science
Added: January 31, 2022

Tension wood (TW) is a specialized xylem tissue formed in angiosperm trees under gravitational stimulus or mechanical stresses (e.g., bending). The genetic regulation that underlies this important mechanism remains poorly understood. Here, we used laser capture microdissection of stem xylem cells coupled with full transcriptome RNA-sequencing to analyze TW formation in Populus trichocarpa. After tree bending, PtrLBD39 was the most significantly induced transcription factor gene; it has a phylogenetically paired homolog, PtrLBD22. CRISPR-based knockout of PtrLBD39/22 severely inhibited TW formation, reducing cellulose and increasing lignin content. Transcriptomic analyses of CRISPR-based PtrLBD39/22 double mutants showed that these two genes regulate a set of TW-related genes. Chromatin immunoprecipitation sequencing (ChIP-seq) was used to identify direct targets of PtrLBD39. We integrated transcriptomic analyses and ChIP-seq assays to construct a transcriptional regulatory network (TRN) mediated by PtrLBD39. In this TRN, PtrLBD39 directly regulates 26 novel TW-responsive transcription factor genes. Our work suggests that PtrLBD39 and PtrLBD22 specifically control TW formation by mediating a TW-specific TRN in Populus.