Evolutionary origin of a new gene drives root growth in one desert poplar
Chengyu Gao, Xiaotao Bai, Qianqian Wei, Xuemin Shao, Pan Zhang, Qi Zhang, Junjie Wang, Dongshi Wan, Jianquan LiuSummary
Populus euphratica
develops an extensive root system that supports survival in arid environments. We identified
PeuPLDζ4
, a new gene arising from tandem duplication in
P. euphratica
, and evaluated its effects on root growth and drought‐related performance.
Phylogenetic and promoter‐reporter analyses, enzyme assays, and subcellular localization characterized
PeuPLDζ4
divergence. Its effects were evaluated in transgenic
Arabidopsis thaliana
,
P. alba
var.
pyramidalis
, wheat, and rice. Phosphatidic acid (PA) and hormone measurements, reporter imaging, transcriptomics, protein–lipid overlay, dual‐luciferase, and electrophoretic mobility shift assays investigated the mechanism.
Compared with its paralog
PeuPLDζ3
,
PeuPLDζ4
showed drought‐inducible root expression, higher enzymatic activity, and additional nuclear‐associated localization.
PeuPLDζ4
overexpression promoted root growth across species and was associated with increased PA accumulation in root‐tip tissues, elevated auxin (IAA) and cytokinin (CK) contents, enhanced IAA and CK reporter responses, and an increased IAA : CK ratio. NAC097 was identified as a PA‐associated candidate regulator that bound and activated the LONELY GUY 2 (
LOG2
) and IIOPENTENYLTRANSFERASE 4 (
IPT4
) promoters.
These findings indicate that functional divergence of a newly duplicated
PLDζ
gene contributed to root‐related adaptation in
P. euphratica
. The PA‐associated NAC097–
LOG2
/
IPT4
branch provides a candidate link between lipid signaling and CK regulation, while
PeuPLDζ4
may offer a resource for improving drought‐related traits in crops.