Functional Conservation of the DDP1-type Inositol Pyrophosphate Phosphohydrolases in Land Plant.

Inositol pyrophosphates (PP-InsPs) are eukaryote-specific second messengers that regulate diverse cellular processes, including immunity, nutrient sensing, and hormone signaling pathways in plants. These energy-rich messengers exhibit high sensitivity to the cellular phosphate status, suggesting that the synthesis and degradation of PP-InsPs are tightly controlled within the cells. Notably, the molecular basis of PP-InsP hydrolysis in plants remains largely unexplored. In this study, we report the functional characterization of MpDDP1, a diadenosine and diphosphoinositol polyphosphate phosphohydrolase encoded by the genome of the liverwort, . We show that MpDDP1 functions as a PP-InsP phosphohydrolase in different heterologous organisms. Consistent with this finding, plants defective in MpDDP1 exhibit elevated levels of 1/3-InsP and 1/3,5-InsP, highlighting the contribution of MpDDP1 in regulating PP-InsP homeostasis . Furthermore, our study reveals that MpDDP1 controls thallus development and vegetative reproduction in . Collectively, this study provides insights into the regulation of specific PP-InsP messengers by DDP1-type phosphohydrolases in land plants.