Genome‑wide identification of NAC transcription factor family members and functional characterization of FaNAC7‑Fve6 in low‑temperature tolerance via the ROS scavenging pathway in Fragaria × ananassa.

NAC transcription factors are key regulators of plant growth and stress responses, but their role in low-temperature tolerance of octoploid strawberry (Fragaria × ananassa) remains largely unexplored. In particular, little is known about the evolutionary characteristics of the NAC gene family in this species or the molecular mechanisms by which these genes mediate low-temperature stress responses. Here, we identified 371 FaNAC genes unevenly distributed across 28 chromosomes, with the Fve subgenome being the most abundant. Members of the same subgroup share highly conserved gene structures and motifs. Promoter analysis revealed cis-elements responsive to plant hormones (MeJA, ABA) and abiotic stresses including low-temperature, drought, and anaerobic. Most FaNAC‑Fve genes responded transcriptionally to low-temperature. One representative, FaNAC7-Fve6, localized to the nucleus and exhibited transcriptional self-activation activity. RT‑qPCR revealed that FaNAC7‑Fve6 was markedly induced by low-temperature, salt, heat, drought and ABA treatments. Overexpression of FaNAC7-Fve6 in 'Asia' strawberry enhanced the expression of antioxidant enzyme genes and reduced reactive oxygen species (ROS) accumulation. These findings reveal the evolutionary expansion of the FaNAC gene family in octoploid strawberry and establish a molecular mechanism whereby FaNAC7-Fve6 enhances low-temperature tolerance via the ROS scavenging pathway, providing valuable genetic targets for improving strawberry low-temperature stress resistance.