Genome-wide identification and functional characterization of ABA and salt stress responsive AITRs transcriptional repressors genes in sweet potato (Ipomoea batatas)

BACKGROUND: Abscisic acid (ABA) is a hormone that regulates plant responses to abiotic stress through complex signaling pathway. ABA-induced transcription repressors (AITRs), are a family of transcription factors involved in ABA signaling and abiotic stresses responses. Sweet potato (Ipomoea batatas) is an important crop for food, raw materials, and bioenergy, but its productivity is often affected by environmental stresses. RESULTS: In this study, 19 IbAITRs were identified in sweet potato genome and they were distributed across 16 chromosomes. IbAITRs gene structures were highly conserved, with no introns observed and phylogenetic analysis grouped them into two major clades with AITRs from other species. The promoter revealed multiple hormone and stress-responsive cis-elements, including ABRE motifs associated with ABA signaling. Quantitative RT-PCR analysis showed that IbAITRs are expressed in multiple tissues, particularly in shoots, young leaves, initiating tuberous roots, and mature tuberous root, and their expression is induced by ABA and salt treatments. Transfection assays demonstrated that IbAITR11, IbAITR12, and IbAITR13 are nuclear proteins that function as transcriptional repressors. CONCLUSION: Our results indicate that IbAITR genes are involved in ABA- and salt-responsive regulatory networks in sweet potato. This study provides a foundation for future functional studies and highlights IbAITRs as potential targets for improving abiotic stress tolerance through molecular breeding.