miR169f regulation by lncRNA LASSO fine‐tunes JA ‐dependent root immunity in rice

Root immunity is vital for defending plants against soilborne pathogens, yet the regulatory mechanisms underlying this process remain incompletely understood. Here, we characterize a novel regulatory module comprising the long non-coding RNA LASSO, microRNA miR169f, and the transcription factor NF-YA1 that regulates rice root immunity. miR169f overexpression lines were generated and investigated using pathogen susceptibility assays, transcriptome analysis (mRNA-seq), and hormone measurements. Target genes were validated using 5' RLM-RACE (RNA Ligase-Mediated Rapid Amplification of cDNA Ends), degradome sequencing, transient co-expression in Nicotiana benthamiana, and RT-qPCR was used to validate and extend the transcriptome dataset. miR169f-overexpression plants exhibit reduced susceptibility to nematodes and the oomycete Pythium arrhenomanes. On the contrary, lines with reduced miR169f expression (STTM169f) as well as LASSO- and NF-YA1-overexpression lines show enhanced susceptibility. LASSO is rapidly induced in roots in response to nematode secretions, and most likely acts as a target mimic that sequesters miR169f, thereby relieving repression of NF-YA1. The miR169f fine-tunes defence responses by influencing the jasmonic acid (JA) pathway under basal conditions while enabling strong JA-responsive gene activation during nematode infection. This dynamic regulation links post-transcriptional control with hormone signalling to shape root immunity. Together, our results reveal a previously uncharacterized non-coding RNA network that orchestrates root defence responses.