The study engineers Type‑B response regulators to alter their transcriptional activity and cytokinin sensitivity, enabling precise modulation of cytokinin‑dependent traits. Using tissue‑specific promoters, the synthetic transcription factors were deployed in Arabidopsis thaliana to reliably increase or decrease lateral root numbers, demonstrating a modular platform for controlling developmental phenotypes.

The study characterizes the tomato class B heat shock factor SlHSFB3a, revealing its age‑dependent expression in roots and its role in enhancing lateral root density by modulating auxin homeostasis. Overexpression of SlHSFB3a increases lateral root emergence, while CRISPR‑mediated knockouts produce the opposite phenotype, indicating that SlHSFB3a regulates auxin signaling through repression of auxin repressors and activation of the ARF7/LOB20 pathway.

The study introduces a minimal precursor platform for synthetic trans-acting siRNAs (syn-tasiRNAs) in tomato, leveraging the endogenous SlmiR482b microRNA to produce functional silencing agents in both transgenic and virus-induced gene silencing (VIGS) systems. Minimal precursors successfully silenced endogenous genes and conferred resistance to tomato spotted wilt virus, and a transgene‑free delivery via crude extracts was demonstrated, highlighting a versatile tool for precision RNAi in Solanum lycopersicum.