Species	Reference gene ID	Possible function	Papers / DOI
Arabidopsis	At2g26660	May inhibit PHR1 DNA-binding activity in a Pi-dependent manner.	SPX1 is a phosphate-dependent inhibitor of Phosphate Starvation Response 1 in Arabidopsis.; 2014; DOI: 10.1073/pnas.1404654111; PMID: 25271326; https://pubmed.ncbi.nlm.nih.gov/25271326/
Arabidopsis	At5g20150	Plays a positive role in plant adaptation to phosphate starvation.	Characterization of a sub-family of Arabidopsis genes with the SPX domain reveals their diverse functions in plant tolerance to phosphorus starvation.; 2008; DOI: 10.1111/j.1365-313x.2008.03460.x; PMID: 18315545; https://pubmed.ncbi.nlm.nih.gov/18315545/ | SPX1 is a phosphate-dependent inhibitor of Phosphate Starvation Response 1 in Arabidopsis.; 2014; DOI: 10.1073/pnas.1404654111; PMID: 25271326; https://pubmed.ncbi.nlm.nih.gov/25271326/
Rice	UniProt: B8B4D0	Involved in plant adaptation to phosphate (Pi) starvation (By similarity).	No verified direct reference in this release
Rice	Os06g0603600	Involved in plant adaptation to phosphate (Pi) starvation.	Involvement of OsSPX1 in phosphate homeostasis in rice.; 2009; DOI: 10.1111/j.1365-313x.2008.03734.x; PMID: 19000161; https://pubmed.ncbi.nlm.nih.gov/19000161/ | Regulation of OsSPX1 and OsSPX3 on expression of OsSPX domain genes and Pi-starvation signaling in rice.; 2009; DOI: 10.1111/j.1744-7909.2009.00834.x; PMID: 19566645; https://pubmed.ncbi.nlm.nih.gov/19566645/ | OsSPX1 suppresses the function of OsPHR2 in the regulation of expression of OsPT2 and phosphate homeostasis in shoots of rice.; 2010; DOI: 10.1111/j.1365-313x.2010.04170.x; PMID: 20149131; https://pubmed.ncbi.nlm.nih.gov/20149131/ | Rice SPX1 and SPX2 inhibit phosphate starvation responses through interacting with PHR2 in a phosphate-dependent manner.; 2014; DOI: 10.1073/pnas.1404680111; PMID: 25271318; https://pubmed.ncbi.nlm.nih.gov/25271318/ | An SPX-RLI1 Module Regulates Leaf Inclination in Response to Phosphate Availability in Rice.; 2018; DOI: 10.1105/tpc.17.00738; PMID: 29610209; https://pubmed.ncbi.nlm.nih.gov/29610209/
Rice	UniProt: A2X254	Inhibits PHR2 DNA-binding activity via a phosphate (Pi)-dependent protein interaction (By similarity).	No verified direct reference in this release