Systematic identification and response patterns of BRX orthologs from Camellia sinensis under stress and gibberellin regulation

Abstract

[Objective] Identification and characterization of the BRX family genes in tea plants, along with analysis of their expression patterns in various tissues and under stress conditions. The research lays the groundwork for investigation into the functions of the tea plant BRX genes. [Methods] Using the tea plant genome database and bioinformatics softwares such as TBtools, we identified and analyzed the BRX genes with the tea plant variety ‘Shuchazao’. Different treatments, including salt, drought, high temperature, and low temperature stress, as well as exogenous GA3 application, were applied for various durations. The relative transcript abundance of the BRX gene family in different tissues and under stress conditions was quantified using RT-qPCR. [Results] A total of 5 CsBRX genes was identified, encoding proteins composed of 313-370 amino acids. The structure of genes was similar and highly conserved. The promoter regions contained hormone and stress response elements. Based on evolutionary relationships, BRX proteins were divided into 4 subfamilies. CsBRX1, CsBRX3, and CsBRX5 were all expressed in young leaves, while CsBRX4 was exclusively expressed in old leaves. Under salt stress for 12 h, the transcriptional levels of CsBRX1, CsBRX2, and CsBRX4 were elevated to the greatest extend. CsBRX2 exhibited a swift response to low temperature stress, with its relative expression peaked at 1 h. CsBRX2 demonstrated a positive response to exogenous GA signaling, and its expression reached a peak at 24 h interval. [Conclusion] The CsBRX genes demonstrate tissue-specific expression patterns, responding variably to multiple stresses and GA signal, which offers insights into stress tolerance mechanisms of tea plants.

Keywords

• camellia sinensis
• brx gene family
• bioinformatics
• tissue-specific
• abiotic stress
• expression analysis