Genome-wide analysis of the TAF gene family reveals a role for GhTAF8 in cottonseed oil accumulation

TATA-box binding protein (TBP) associated factors (TAFs), together with TBP, com-pose transcription factor IID (TFIID), which is an essential complex for transcription initiation and regulation. TAFs are involved in regulating plant development. However, genome-wide identification and expression pattern analysis of TAFs in cotton remain unreported. In this study, a total of 124 TAF genes were identified in four Gossypium species. TAFs were divided into six subgroups based on the phylogenetic tree analysis. Analysis of collinearity and selection pressure indicated that TAF gene pairs have undergone strong purifying selection during evolution. Gene expression analysis of GhTAFs revealed that TAFs are expressed at all stages of cotton ovule development. Furthermore, a set of key GhTAF genes was identified, which are specifically or constitutively highly expressed across multiple stages of cotton ovule development. Weighted gene co-expression network analysis prioritized GhTAF8 ( Ghir_D11G035840 ) from the blue module associated with 20 days post anthesis, a critical stage of rapid oil accumulation. GhTAF8 exhibited the highest module membership among the nine GhTAFs in this module. Overexpression of GhTAF8 in Arabidopsis thaliana increased seed oil content, whereas virus-induced gene silencing in cotton reduced seed oil content. A GhTAF8 -centered co-expression network also identified genes potentially associated with seed development and lipid metabolism. These findings support a functional association between GhTAF8 and seed oil accumulation and provide a foundation for investigating its underlying regulatory mechanisms.