The fnr-like mutants confer isoxaben tolerance by initiating mitochondrial retrograde signalling

Ronan C. Broad, Michael Ogden, Arka Dutta, Peter M. Dracatos, James Whelan, Staffan Persson, Ghazanfar Abbas Khan*

*Corresponding author af dette arbejde

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Abstract

Isoxaben is a pre-emergent herbicide used to control broadleaf weeds. While the phytotoxic mechanism is not completely understood, isoxaben interferes with cellulose synthesis. Certain mutations in cellulose synthase complex proteins can confer isoxaben tolerance; however, these mutations can cause compromised cellulose synthesis and perturbed plant growth, rendering them unsuitable as herbicide tolerance traits. We conducted a genetic screen to identify new genes associated with isoxaben tolerance by screening a selection of Arabidopsis thaliana T-DNA mutants. We found that mutations in a FERREDOXIN-NADP(+) OXIDOREDUCTASE-LIKE (FNRL) gene enhanced tolerance to isoxaben, exhibited as a reduction in primary root stunting, reactive oxygen species accumulation and ectopic lignification. The fnrl mutant did not exhibit a reduction in cellulose levels following exposure to isoxaben, indicating that FNRL operates upstream of isoxaben-induced cellulose inhibition. In line with these results, transcriptomic analysis revealed a highly reduced response to isoxaben treatment in fnrl mutant roots. The fnrl mutants displayed constitutively induced mitochondrial retrograde signalling, and the observed isoxaben tolerance is partially dependent on the transcription factor ANAC017, a key regulator of mitochondrial retrograde signalling. Moreover, FNRL is highly conserved across all plant lineages, implying conservation of its function. Notably, fnrl mutants did not show a growth penalty in shoots, making FNRL a promising target for biotechnological applications in breeding isoxaben tolerance in crops.
OriginalsprogEngelsk
TidsskriftPlant Biotechnology Journal
Vol/bind22
Udgave nummer11
Sider (fra-til)3000-3011
ISSN1467-7644
DOI
StatusUdgivet - 2024

Bibliografisk note

Funding Information:
G.A.K. is funded by a DECRA Fellowship from the Australian Research Council (DE210101200). S.P. was funded by a Villum Foundation grant, two Novo Nordisk grants, and a Danish National Research Foundation grant (25915, 19OC0056076, 20OC0060564 and DNRF155 respectively).

Publisher Copyright:
© 2024 The Author(s). Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

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