Interaction between OsLEC1 and OsHDA710 positively regulates callus formation in rice

Transgenic and gene editing technologies often begin with callus induction through embryo in vitro culture in rice. Mutations in both OsLEC1 (the rice homolog of Leafy Cotyledon 1) and OsHDA710 (encoding a deacetylase) can severely impair callus induction in embryo culture. However, whether these genes are part of a common regulatory module remains unclear. This study demonstrates defective scutellum-derived callus induction in novel OsLEC1 knockout (Oslec1) lines, indicating its crucial role in this process. Immunoprecipitation-mass spectrometry assays revealed that OsHDA710 interacts with OsLEC1 in embryo-derived callus. Yeast two-hybrid and bimolecular fluorescence complementation assays confirmed that OsLEC1 interacts with OsHDA710 via its C-terminal domain. Comparative transcriptome analyses revealed a set of shared genes that were upregulated in scutellum-derived callus of both Oslec1 and Oshda710 mutants. The upregulated genes included the nuclear factor Y family transcription factors, as well as genes involved in hormone biosynthesis and signaling, starch and lipid synthesis and metabolism, and abiotic stress responses. Our study indicates that OsLEC1 and OsHDA710 collaborate to regulate callus induction in rice through a common pathway.