A New Start: Investigating The Role Of The Transcription Factor PDF2 In Arabidopsis

The study investigates the role of the transcription factor PDF2 in Arabidopsis, focusing on its lipid-sensing capabilities via the START domain. PDF2, along with its paralog ATML1, is crucial for epidermal specification and is activated by gibberellic acid. The research identified that PDF2 binds specifically to lyso-PC, a lipid species, suggesting that PDF2 functions as a lyso-PC sensor. This binding was confirmed through various assays, including mass spectrometry and microscale thermophoresis. PDF2 was shown to regulate genes involved in phospholipid remodeling and phosphate starvation response, acting as a transcriptional repressor for GDPD1 and SPX1. The study also found that PDF2 influences root growth, with mutants showing reduced root length and overexpressors showing enlarged roots. This suggests that PDF2 adjusts membrane lipid synthesis in response to phosphate availability, linking metabolic states to cell growth and differentiation. The findings open questions about the broader role of PDF2 and other HD-Zip IV transcription factors in stress responses and lipid sensing.