Adventitious root (AR) formation is important for the vegetative
propagation. The effects of strigolactones (SLs) on AR formation have
been rarely reported, especially in woody plants. In this study, we
first verified the inhibitory effects of SLs on AR formation in apple
materials. Transcriptome analysis identified 12,051 differentially
expressed genes over the course of AR formation, with functions related
to organogenesis, cell wall biogenesis or plant senescence. WGCNA
suggests SLs might inhibit AR formation through repressing the
expression of two core hub genes, MdLAC3 and MdORE1. We
further verified that enhanced cell wall formation and accelerated
senescence were involved in the AR inhibition caused by SLs. Combining
small RNA and degradome sequencing, as well as a dual-luciferase sensor
system, we identified and validated three negatively correlated
miRNA–mRNA pairs, including mdm-miR397–MdLAC3 involved in
secondary cell wall formation, and mdm-miR164a/b–MdORE1 involved
in senescence. Finally, we have experimentally demonstrated the role of
mdm-miR164b–MdORE1 in SLs-mediated inhibition of AR formation.
Overall, our findings not only propose a comprehensive regulatory
network for the function of SLs on AR formation, but also provide novel
candidate genes for the potential genetic improvement of AR formation in
woody plants using transgenic or CRISPR technology.
A specific role of iron in promoting meristematic cell division during adventitious root formation
