The TCP transcription factor (TF) family is a vital set of plant-specific regulators involved in plant growth, development, and responses to environmental stresses. Despite the extensive research on TCP transcription factors in numerous plant species, the functions they fulfill in Betula platyphylla are still not well understood. In this study, 21 BpTCP genes were identified via genome-wide analysis. Bioinformatics analysis was used to examine the physicochemical properties of these transcription factors, including molecular weight, isoelectric point, chromosomal distribution, and predicted subcellular localization. We expected that most BpTCP transcription factors would be located in the nucleus. Collinearity analysis revealed that gene fragment duplication events played a major role in the evolutionary expansion and diversification of the BpTCP gene family. Promoter analysis identified diverse cis-acting elements in BpTCP, suggesting that they play a role in stress responses, hormonal regulation, and plant growth and development. qRT-PCR analysis showed that BpTCP genes displayed tissue-specific expression patterns in the roots, stems, and leaves, displaying remarkable differences in expression levels when subjected to abiotic stresses, including drought and high- and low-temperature conditions. Notably, BpTCP17 and BpTCP18 showed markedly higher expression levels under multiple stress conditions. Subcellular localization experiments confirmed that both BpTCP17 and BpTCP18 localize in the nucleus, consistent with bioinformatic predictions. These findings emphasize the potential roles of BpTCP17 and BpTCP18 in mediating abiotic stress responses, highlighting their potential as candidate genes for improving stress tolerance in B. platyphylla.

Heat stress transcription factors (HSFs) play a critical role in orchestrating cellular responses to elevated temperatures and various stress conditions. While extensively studied in model plants, the HSF gene family in Betula platyphylla remains unexplored, despite the availability of its sequenced genome. In this study, we employed bioinformatics approaches to identify 21 BpHSF genes within the Betula platyphylla genome, revealing their uneven distribution across chromosomes. These genes were categorized into three subfamilies: A, B, and C. Each was characterized by conserved protein motifs and gene structures, with notable divergence observed between subfamilies. Collinearity analysis suggested that segmental duplication events have driven the evolutionary expansion of the BpHSF gene family. Promoter region analysis identified an array of cis-acting elements linked to growth, development, hormonal regulation, and stress responses. Subcellular localization experiments confirmed the nuclear localization of BpHSFA2a, BpHSFB1a, and BpHSFC1a, consistent with in silico predictions. RNA-seq and RT-qPCR analyses revealed tissue-specific expression patterns of BpHSF genes and their dynamic responses to heat stress, with qPCR validation highlighting a significant upregulation of BpHSFA2a under high-temperature conditions. In summary, this study provided a comprehensive characterization of the HSF gene family in Betula platyphylla, laying a solid foundation for future functional studies. Particularly, BpHSFA2a emerges as a promising candidate gene for enhancing heat tolerance in Betula platyphylla, warranting further detailed investigation.

Heat stress transcription factors (HSFs) play a critical role in orchestrating cellular responses to elevated temperatures and various stress conditions. While extensively studied in model plants, the HSF gene family in Betula platyphylla remains unexplored, despite the availability of its sequenced genome. In this study, we employed bioinformatics approaches to identify 21 BpHSF genes within the B. platyphylla genome, revealing their uneven distribution across chromosomes. These genes were categorized into three subfamilies: A, B, and C. Each characterized by conserved protein motifs and gene structures, with notable divergence observed between subfamilies. Collinearity analysis suggested that segmental duplication events have driven the evolutionary expansion of the BpHSF gene family. Promoter region analysis identified an array of cis-acting elements linked to growth, development, hormonal regulation, and stress responses. Subcellular localization experiments confirmed the nuclear localization of BpHSFA2a, BpHSFB1a, and BpHSFC1a, consistent with in silico predictions. RNA-seq and RT-qPCR analyses revealed tissue-specific expression patterns of BpHSF genes and their dynamic responses to heat stress, with qPCR validation highlighting a significant upregulation of BpHSFA2a under high-temperature conditions. In summary, this study provided a comprehensive characterization of the HSF gene family in B. platyphylla, laying a solid foundation for future functional studies. Particularly, BpHSFA2a emerges as a promising candidate gene for enhancing heat tolerance in B. platyphylla, warranting further detailed investigation.