Submitted to: Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/28/2024
Publication Date: 10/30/2024
Citation: Freed, C., Craige, B., Donahue, J., Cridland, C., Williams, S.P., Pereira, C., Kim, J., Blice, H.C., Owen Jr, J.S., Gillaspy, G. 2024. Using native plant and synthetic genes to disrupt inositol pyrophosphates and phosphate accumulation in plants. Plant Physiology. Article #kiae582. https://doi.org/10.1093/plphys/kiae582.
DOI: https://doi.org/10.1093/plphys/kiae582

Interpretive Summary: The phosphorous crisis is a complicated issue that will require a variety of innovative strategies to circumvent both phosphorous deficiency (potential shortages and deficient soils) and surplus (watershed pollution and saturated lands). As the global population increases, there is a need for farmers to increase fertilizer inputs as crop production also increases. Between global food demand and higher fertilizer usage in urban areas, there is a subsequent increase in fertilizer runoff into the watersheds. One strategy that can be used is phosphorous phytoremediation by leveraging plants to absorb excess phosphorous from polluted water and soil. Genetic over expression of a protein (DDP1) in both a model species and cover crop provide unique germplasm to study how decreased signaling molecules (PP-InsPs ) impact plant growth, physiology, and phosphorous accumulation. This is the first study, to our knowledge, that synthetically modulates signaling molecules (PP-InsPs) to increase phosphorous accumulation. in the right context, could be useful for Pi reclamation. Tansgenic plants results in alterations in plant growth and sensitivity to exogenously applied phosphate. Pennycress plants expressing DDP1 protein displayed increases in phosphate accumulation, suggesting that these plants could potentially serve to reclaim phosphate from phosphate-polluted soils. The strategy we report here represents a first step in altering signaling molecules for continual accumulation of phosphorous from soil, a key step for future development of unique plants to remediate phosphorous -polluted environments.

Technical Abstract: Inositol pyrophosphates are eukaryotic signaling molecules that have been recently identified as key regulators of plant phosphate sensing and homeostasis. Given the importance of phosphate to current and future agronomic practices, we sought to design plants which could be used to sequester phosphate, as a first step in a phytoremediation strategy. To achieve this, we expressed DDP1, a Saccharomyces cerevisiae enzyme demonstrated to hydrolyze inositol pyrophosphates, in Arabidopsis thaliana and Thlaspi arvense (pennycress), a spring annual cover crop with emerging importance as a biofuel crop. DDP1 expression in Arabidopsis decreased inositol pyrophosphates, activated Phosphate Starvation Response marker genes, and increased phosphate accumulation. These changes correlated with alterations in plant growth and sensitivity to exogenously applied phosphate. Pennycress plants expressing DDP1 displayed increases in phosphate accumulation, suggesting that these plants could potentially serve to reclaim phosphate from phosphate-polluted soils. We also identified a native Arabidopsis gene, NUDIX13, which we show encodes an enzyme homologous to DDP1 with similar substrate specificity. Arabidopsis transgenics overexpressing NUDIX13 had lower inositol pyrophosphate levels and displayed phenotypes similar to DDP1 overexpressing transgenics, while nudix 13-1 mutants had increased levels of inositol pyrophosphates. Taken together, our data demonstrates that DDP1 and NUDIX13 can be used in strategies to regulate plant inositol pyrophosphates and could serve as potential targets for engineering plants to reclaim phosphate from polluted environments.