Format

Send to

Choose Destination
Mol Plant Pathol. 2018 Oct;19(10):2333-2348. doi: 10.1111/mpp.12702. Epub 2018 Aug 31.

Massive up-regulation of LBD transcription factors and EXPANSINs highlights the regulatory programs of rhizomania disease.

Author information

1
Department of Plant Biology, Uppsala BioCenter SLU, Swedish University of Agricultural Sciences, Linnean Center for Plant Biology, 75007, Uppsala, Sweden.
2
Institute of Sugar Beet Research, Department of Phytopathology, 37079, Göttingen, Germany.
3
MariboHilleshög Research AB, 26123, Landskrona, Sweden.
4
Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, 67084, Strasbourg, France.
5
Institute of Horticultural Production Systems, Department of Phytomedicine, Leibniz University Hannover, 30419, Hannover, Germany.

Abstract

Rhizomania of sugar beet, caused by Beet necrotic yellow vein virus (BNYVV), is characterized by excessive lateral root (LR) formation leading to dramatic reduction of taproot weight and massive yield losses. LR formation represents a developmental process tightly controlled by auxin signaling through AUX/IAA-ARF responsive module and LATERAL ORGAN BOUNDARIES DOMAIN (LBD) transcriptional network. Several LBD transcription factors play central roles in auxin-regulated LR development and act upstream of EXPANSINS (EXPs), cell wall (CW)-loosening proteins involved in plant development via disruption of the extracellular matrix for CW relaxation and expansion. Here, we present evidence that BNYVV hijacks these auxin-regulated pathways resulting in formation LR and root hairs (RH). We identified an AUX/IAA protein (BvAUX28) as interacting with P25, a viral virulence factor. Mutational analysis indicated that P25 interacts with domains I and II of BvAUX28. Subcellular localization of co-expressed P25 and BvAUX28 showed that P25 inhibits BvAUX28 nuclear localization. Moreover, root-specific LBDs and EXPs were greatly upregulated during rhizomania development. Based on these data, we present a model in which BNYVV P25 protein mimics action of auxin by removing BvAUX28 transcriptional repressor, leading to activation of LBDs and EXPs. Thus, the evidence highlights two pathways operating in parallel and leading to uncontrolled formation of LRs and RHs, the main manifestation of the rhizomania syndrome.

KEYWORDS:

P25 virulence factor; beet necrotic yellow vein virus; expansin; rhizomania

PMID:
30011123
DOI:
10.1111/mpp.12702

Supplemental Content

Full text links

Icon for Wiley
Loading ...
Support Center