Unveiling the role of BrREM1.4: a key regulator in plant growth and abiotic stress adaptation in turnip (Brassica rapa)

Remorins (REMs) are plant-specific proteins known for their diverse biological functions. However, their roles in plant growth, development, and responses to abiotic stress remain largely unexplored. In this study, we investigated the function of BrREM1.4 (PQ810929), a protein isolated from the turnip (Brassica rapa) cv. Tsuda in growth, development, and resistance to saline–alkaline stress. Quantitative PCR analysis revealed that BrREM1.4 showed tissue-specific expression, with the highest levels detected in the petals. The transcription levels of BrREM1.4 in turnip seedlings (1–7 days old) were significantly higher under natural light conditions compared with dark conditions. Furthermore, the expression of BrREM1.4 was upregulated in response to extreme temperatures, saline–alkaline stress, and drought stress. Heterologous overexpression of BrREM1.4 in tobacco (Nicotiana tabacum) resulted in increased plant height, leaf number, root length, branching, and 100-grain weight although it significantly reduced the seed setting rate. Compared with wild-type tobacco, plants overexpressing BrREM1.4 exhibited enhanced tolerance to salt (NaCl) and alkali (NaHCO3) stresses. These findings suggest that BrREM1.4 plays a crucial role in plant growth and development, as well as in the adaptation to various abiotic stresses.