Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Ji'nan, Shandong, P.R. China.
Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Sciences, Beijing Normal University, 19 Xinjiekouwai Avenue, Beijing, 100875, China.
Plant J. 2024 Jan;117(2):498-515. doi: 10.1111/tpj.16505. Epub 2023 Oct 19.
Salt glands are the unique epidermal structures present in recretohalophytes, plants that actively excrete excess Na by salt secretory structures to avoid salt damage. Here, we describe a transmembrane protein that localizes to the plasma membrane of the recretohalophyte Limonium bicolor. As virus-induced gene silencing of the corresponding gene LbRSG in L. bicolor decreased the number of salt glands, we named the gene Reduced Salt Gland. We detected LbRSG transcripts in salt glands by in situ hybridization and transient transformation. Overexpression and silencing of LbRSG in L. bicolor pointed to a positive role in salt gland development and salt secretion by interacting with Lb3G16832. Heterologous LbRSG expression in Arabidopsis enhanced salt tolerance during germination and the seedling stage by alleviating NaCl-induced ion stress and osmotic stress after replacing or deleting the (highly) negatively charged region of extramembranous loop. After screened by immunoprecipitation-mass spectrometry and verified using yeast two-hybrid, PGK1 and BGLU18 were proposed to interact with LbRSG to strengthen salt tolerance. Therefore, we identified (highly) negatively charged regions in the extramembrane loop that may play an essential role in salt tolerance, offering hints about LbRSG function and its potential to confer salt resistance.
盐腺是泌盐植物特有的表皮结构，这些植物通过盐分泌结构主动排出多余的 Na，以避免盐害。在这里，我们描述了一种定位于泌盐植物二色补血草（Limonium bicolor）质膜的跨膜蛋白。由于病毒诱导的 LbRSG 基因沉默降低了盐腺的数量，我们将该基因命名为 Reduced Salt Gland。通过原位杂交和瞬时转化，我们在盐腺中检测到 LbRSG 转录本。LbRSG 在二色补血草中的过表达和沉默表明，它通过与 Lb3G16832 相互作用，在盐腺发育和盐分泌中发挥积极作用。在拟南芥中异源表达 LbRSG 通过取代或删除跨膜环中带负电荷的区域减轻 NaCl 诱导的离子胁迫和渗透胁迫，从而增强了萌发和幼苗期的耐盐性。通过免疫沉淀-质谱筛选和酵母双杂交验证，提出 PGK1 和 BGLU18 与 LbRSG 相互作用以增强耐盐性。因此，我们确定了跨膜环中带负电荷的区域可能在耐盐性中发挥重要作用，这为 LbRSG 功能及其赋予耐盐性的潜力提供了线索。
