Unveiling the Regulatory
Role of miRNAs in Internode
Elongation: Integrated Analysis of MicroRNA and mRNA Expression Profiles
across Diverse Dwarfing Treatments in Maize (Zea mays L.)
MicroRNAs are crucial regulators of gene expression in
maize. However,
the mechanisms through which miRNAs control internode elongation remain
poorly understood. This study engineered varying levels of internode
elongation inhibition, revealing that dwarfing treatments diminished
gibberellin levels, curtailed cell longitudinal growth, and slowed
the rate of internode elongation. Comprehensive transcriptome and
miRNA profiling of the internode elongation zone showed gene expression
changes that paralleled the extent of the internode length reduction.
We identified 543 genes and 29 miRNAs with significant correlations
to internode length, predominantly within families, including miR164
and miR396. By incorporating target gene expression levels, we pinpointed
nine miRNA-mRNA pairs that are significantly associated with the regulation
of the internode elongation. The inhibitory effects of these miRNAs
on their target genes were confirmed through dual-luciferase reporter
assays. Overexpression of miR164h in maize resulted in increased internode
and cell length, suggesting a novel genetic avenue for manipulating
plant stature. These miRNAs may also serve as precise spatiotemporal
regulators for in vitro plant development.