Epigenetic silencing of callose synthase by VIL1 promotes bud-growth transition in lily bulbs

In plants, restoring intercellular communication is required for cell activity in buds during the growth transition from slow to fast growth after dormancy release. However, the epigenetic regulation of this phenomenon is far from understood. Here we demonstrate that lily VERNALIZATION INSENSITIVE 3-LIKE 1 (LoVIL1) confers growth transition by mediating plasmodesmata opening via epigenetic repression of CALLOSE SYNTHASE 3 (LoCALS3). Moreover, we found that a novel transcription factor, NUCLEAR FACTOR Y, SUBUNIT A7 (LoNFYA7), is capable of recruiting the LoVIL1-Polycomb Repressive Complex 2 (PRC2) and enhancing H3K27me3 at the LoCALS3 locus by recognizing the CCAAT cis-element (Cce) of its promoter. The LoNFYA7-LoVIL1 module serves as a key player in orchestrating the phase transition from slow to fast growth in lily bulbs. These studies also indicate that LoVIL1 is a suitable marker for the bud-growth-transition trait following dormancy release in lily cultivars.

Automated summary

Restoring intercellular communication is crucial for cell activity in buds during the transition from slow to fast growth in plants after dormancy release. However, the epigenetic regulation of this process is not well understood. This study shows that the lily gene LoVIL1 mediates plasmodesmata opening by repressing CALLOSE SYNTHASE 3 (LoCALS3) through epigenetic mechanisms. Furthermore, a transcription factor called LoNFYA7 recruits the LoVIL1-Polycomb Repressive Complex 2 (PRC2) to enhance H3K27me3 at the LoCALS3 locus, facilitating the growth transition in lily bulbs.