Qian Shen, Yanhui Shen, Huijuan Ma, Siping Zhang, Shaodong Liu, Ruihua Liu, Changwei Ge, Chaoyou Pang
Transcriptome analysis revealed that GhNAC029 expression was rapidly upregulated within 1 h of cold treatment. Functional analyses showed that GhNAC029 knockout (KO) lines exhibited enhanced cold tolerance, higher survival and increased reactive oxygen species (ROS) scavenging capacity compared with overexpression (OE) and wild-type (WT) plants. GhNAC029, a NAC transcription factor, directly regulated 549 cold-responsive (COR) genes and bound to the G-box motif (5′-CACGTG-3′). A zinc-finger transcription factor (GhZAT10) and an ethylene-response factor (GhERF4) were identified as direct downstream targets, with their expression elevated in KO plants. The upstream regulator inducer of CBF expression 1 (GhICE1) binds to the GhNAC029 promoter and negatively regulates its expression. Silencing GhICE1 caused severe leaf wilting and plant death under cold stress, confirming its positive role in cold tolerance. These findings establish an ICE1–GhNAC029–COR regulatory network that elucidates the molecular basis of GhNAC029-mediated cold responses. GhNAC029 knockout (KO) lines exhibit enhanced cold tolerance, higher survival, and increased ROS scavenging capacity compared with overexpression (OE) and wild-type (WT) plants. GhNAC029 directly regulates 549 cold-responsive (COR) genes and binds to the G-box motif. GhICE1 negatively regulates GhNAC029 expression, and silencing GhICE1 reduces cold tolerance. GhNAC029 negatively regulates cold tolerance in cotton through an ICE1–NAC–COR regulatory module, providing insights for breeding cold-tolerant cotton varieties.
Transcription factors play key roles in plant responses to cold stress; however, the underlying regulatory mechanisms in cotton remain unclear. Transcriptome analysis revealed that GhNAC029 expression was rapidly upregulated within 1 h of cold treatment. Functional analyses showed that, compared with overexpression (OE) and wild-type (WT) plants, GhNAC029 knockout (KO) lines exhibited enhanced cold tolerance, higher survival and increased reactive oxygen species (ROS) scavenging capacity. GhNAC029, a member of the NAM, ATAF and CUC (NAC) transcription factor family, directly regulated 549 cold-responsive ( COR ) genes (52.84% of its targets), and bound to the G-box motif (5′-CACGTG-3′). A zinc-finger transcription factor (GhZAT10) and an ethylene-response factor (GhERF4) were identified as direct downstream targets. Their expression was elevated in KO plants, indicating that GhNAC029 functions as a transcriptional repressor of positive regulators of cold tolerance. The upstream regulator inducer of CBF expression 1 ( GhICE1 ) binds to the GhNAC029 promoter and negatively regulates its expression. Silencing GhICE1 caused severe leaf wilting and plant death under cold stress, confirming its positive role in cold tolerance. Collectively, these findings establish an ICE1–GhNAC029–COR regulatory network that elucidates the molecular basis of GhNAC029 -mediated cold responses and provides insights for breeding cold-tolerant cotton varieties.