Functional and transcriptomic characterization of the receptor‐like protein kinase gene GmHSL1b involved in salt stress tolerance in soybean roots

Abstract The survival and adaptation of plants to adverse environmental conditions is crucial and is facilitated by receptor‐like kinases, which act as cell surface receptors for a variety of signals. In this study, we identified a gene, GmHSL1b , encoding a receptor‐like protein kinase that is responsive to abscisic acid (ABA) hormonal signals and is involved in the plant's response to drought and salt stresses. Subcellular localization assays have demonstrated that the GmHSL1b protein is located in the plasma membrane. Overexpression of the GmHSL1b gene in soybean enhanced root growth and development, as well as the plant's tolerance to salt stress, while the gmhsl1b mutant revealed increased sensitivity to salt stress. Comparative transcriptome analysis showed that some genes associated with various biological processes, such as mitogen‐activated protein kinase (MAPK) cascade signaling, plant hormone signaling, cell wall remodeling, calcium signaling, and defense response mechanisms are differentially expressed in GmHSL1b overexpressing roots. Our research indicated that GmHSL1b can regulate the expression level of the candidate aquaporin GmPIP2‐1 , thereby affecting cell water content and the accumulation of reactive oxygen species (ROS) under salt stress. These findings indicate that the GmHSL1b participates in regulating root development and enhancing the tolerance to salt stress, thus offering insights for boosting crop adaptability to environmental stresses.