Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping

SwissProt keyword-derived (SPKW) annotations present in the Sept 2025 goa_uniprot_gcrp snapshot but removed from the current GOA release after GOA retired the keyword2GO pipeline for cellular organisms.
For NSP1, the keyword "Nodulation" mapped to the genuinely correct, core process term GO:0009877 nodulation; its removal left the gene with no nodulation/symbiosis process annotation, so the removal is collateral damage rather than a corrected over-annotation.

Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt

Maps the UniProt subcellular location "Nucleus" to GO:0005634; consistent with NSP1's role as a nuclear GRAS transcription factor.

GO_REF:0000117

Electronic Gene Ontology annotations created by ARBA machine learning models

ARBA machine-learning model assigned "response to symbiotic fungus" (GO:0009610); a reasonable generalization for an NSP-family GRAS regulator but indirect for Medicago NSP1, whose core symbiotic role is rhizobial nodulation.

file:MEDTR/NSP1/NSP1-deep-research-falcon.md

Deep-research report (falcon / Edison Scientific Literature) - functional annotation of Medicago truncatula NSP1 (Q4VYC8).

NSP1 is a plant-specific GRAS-family transcriptional regulator that functions in the nucleus as part of a transcriptional module activated downstream of the common symbiosis signaling pathway; it acts downstream of Nod factor perception, calcium spiking and CCaMK/DMI3 in the core transcriptional response that activates early nodulation genes.
NSP1 is a DNA-binding transcription factor that directly binds the ENOD11 promoter in vitro (EMSA), recognises an AATTT Nodulation Responsive Element (NRE), and forms a complex with NSP2 that associates with the promoters of NF-responsive genes ENOD11, ERN1 and NIN; loss-of-function nsp backgrounds abolish or strongly impair NF-induced transcription of these genes and nodulation.
NSP1 also has a conserved role outside nodulation in strigolactone biosynthesis - nsp1 mutants do not produce strigolactones and show markedly reduced expression of the SL-biosynthetic gene DWARF27 (~90% reduced in nsp mutant backgrounds); NSP1 is expressed mainly in roots and nodules.
The report synthesises the foundational primary studies Hirsch et al. 2009 (The Plant Cell, DOI 10.1105/tpc.108.064501), Liu et al. 2011 (The Plant Cell, DOI 10.1105/tpc.111.089771) and Smit et al. 2005 (Science 308:1789-1791); these are the primary sources for NSP1 DNA-binding, NSP1-NSP2 complex formation and strigolactone regulation.