Ngwenya Samkelisiwe P, Moloi Sellwane J, Shargie Nemera G, Brown Adrian P, Chivasa Stephen, Ngara Rudo
Department of Plant Sciences, University of the Free State, Qwaqwa Campus, P. Bag X13, Phuthaditjhaba 9866, South Africa.
Agricultural Research Council-Grain Crops Institute, P. Bag X1251, Potchefstroom 2520, South Africa.
Plants (Basel). 2024 Jul 6;13(13):1874. doi: 10.3390/plants13131874.
Plants reprogramme their proteome to alter cellular metabolism for effective stress adaptation. Intracellular proteomic responses have been extensively studied, and the extracellular matrix stands as a key hub where peptide signals are generated/processed to trigger critical adaptive signal transduction cascades inaugurated at the cell surface. Therefore, it is important to study the plant extracellular proteome to understand its role in plant development and stress response. This study examined changes in the soluble extracellular sub-proteome of sorghum cell cultures exposed to a combination of sorbitol-induced osmotic stress and heat at 40 °C. The combined stress significantly reduced metabolic activity and altered protein secretion. While cells treated with osmotic stress alone had elevated proline content, the osmoprotectant in the combined treatment remained unchanged, confirming that sorghum cells exposed to combined stress utilise adaptive processes distinct from those invoked by the single stresses applied separately. Reactive oxygen species (ROS)-metabolising proteins and proteases dominated differentially expressed proteins identified in cells subjected to combined stress. ROS-generating peroxidases were suppressed, while ROS-degrading proteins were upregulated for protection from oxidative damage. Overall, our study provides protein candidates that could be used to develop crops better suited for an increasingly hot and dry climate.
植物会重新编程其蛋白质组，以改变细胞代谢，从而有效地适应胁迫。细胞内蛋白质组反应已得到广泛研究，而细胞外基质是一个关键枢纽，肽信号在其中产生/加工，以触发在细胞表面启动的关键适应性信号转导级联反应。因此，研究植物细胞外蛋白质组对于了解其在植物发育和胁迫反应中的作用非常重要。本研究检测了暴露于山梨醇诱导的渗透胁迫和40℃高温联合胁迫下的高粱细胞培养物中可溶性细胞外亚蛋白质组的变化。联合胁迫显著降低了代谢活性并改变了蛋白质分泌。虽然单独用渗透胁迫处理的细胞脯氨酸含量升高，但联合处理中的渗透保护剂保持不变，这证实了暴露于联合胁迫下的高粱细胞利用的适应性过程不同于单独施加单一胁迫所引发的过程。活性氧（ROS）代谢蛋白和蛋白酶在遭受联合胁迫的细胞中鉴定出的差异表达蛋白中占主导地位。产生ROS的过氧化物酶受到抑制，而降解ROS的蛋白被上调以保护细胞免受氧化损伤。总体而言，我们的研究提供了可用于培育更适合日益炎热干燥气候的作物的蛋白质候选物。
