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Title: A transcriptional repressor HVA regulates vascular bundle formation through auxin transport in Arabidopsis stem
Summary Vascular bundles transport water and photosynthate to all organs, and increased bundle number contributes to crop lodging resistance. However, the regulation of vascular bundle formation is poorly understood in the Arabidopsis stem.We report a novel semi‐dominant mutant with high vascular activity,hva‐d, showing increased vascular bundle number and enhanced cambium proliferation in the stem. The activation of a C2H2 zinc finger transcription factor,AT5G27880/HVA, is responsible for thehva‐dphenotype. Genetic, biochemical, and fluorescent microscopic analyses were used to dissect the functions of HVA.HVA functions as a repressor and interacts with TOPLESS via the conserved Ethylene‐responsive element binding factor‐associated Amphiphilic Repression motif. In contrast to the HVA activation line, knockout ofHVAfunction with a CRISPR‐Cas9 approach or expression of HVA fused with an activation domain VP16 (HVA‐VP16) resulted in fewer vascular bundles. Further, HVA directly regulates the expression of the auxin transport efflux facilitatorPIN1, as a result affecting auxin accumulation. Genetics analysis demonstrated that PIN1 is epistatic to HVA in controlling bundle number.This research identifies HVA as a positive regulator of vascular initiation through negatively modulating auxin transport and sheds new light on the mechanism of bundle formation in the stem.  more » « less
Award ID(s):
2049926
PAR ID:
10555940
Author(s) / Creator(s):
; ; ; ; ;
Publisher / Repository:
Wiley-Blackwell
Date Published:
Journal Name:
New Phytologist
Volume:
243
Issue:
5
ISSN:
0028-646X
Page Range / eLocation ID:
1681 to 1697
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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