Arbuscular mycorrhizal symbiosis (AMS), a complex and delicate process, is precisely regulated by a multitude of transcription factors. PHYTOCHROME-INTERACTING FACTORS (PIFs) are critical in plant growth and stress responses. However, the involvement of PIFs in AMS and the molecular mechanisms underlying their regulator functions have not been well elucidated.
Here, researchers show that SlPIF4 negatively regulates the arbuscular mycorrhizal fungi (AMF) colonization and AMS-induced phosphate uptake in tomatoes. Protein-protein interaction studies suggest that SlDELLA interacts with SlPIF4, reducing its protein stability and inhibiting its transcriptional activity towards downstream target genes. This interaction promotes the accumulation of strigolactones (SLs), facilitating AMS development and phosphate uptake. As a transcription factor, SlPIF4 directly transcriptionally regulates genes involved in SLs biosynthesis, including SlCCD7, SlCDD8, and SlMAX1, as well as the AMS-specific phosphate transporter genes PT4 and PT5.
Collectively, the findings uncover a molecular mechanism by which the SlDELLA-SlPIF4 module regulates AMS and phosphate uptake in tomatoes. Researchers clarify a molecular basis for how SlPIF4 interacts with SLs to regulate the AMS and propose a potential strategy to improve phosphate utilization efficiency by targeting the AMS-specific phosphate transporter genes PTs.
Lan Li, Shibei Ge, Liqun He, Ruicheng Liu, Yuhong Mei, Xiaojian Xia, Jingquan Yu, Yanhong Zhou, SlDELLA interacts with SlPIF4 to regulate arbuscular mycorrhizal symbiosis and phosphate uptake in tomato, Horticulture Research, Volume 11, Issue 9, September 2024, uhae195, https://doi.org/10.1093/hr/uhae195
Source: Oxford Academic