Abstract

Cold shock domain proteins (CSPs), initially identified in Escherichia coli, have been demonstrated to play a positive role in cold resistance. Previous studies in wheat, rice, and Arabidopsis have indicated the functional conservation of CSPs in cold resistance between bacteria and higher plants. However, the biological functions of PbrCSPs in pear pollen tubes, which represent the fragile reproductive organs highly sensitive to low temperature, remain largely unknown. In this study, a total of 22 CSPs were identified in the seven Rosaceae species, with a focus on characterizing four PbrCSPs in pear (Pyrus bretschneideri Rehder). All four PbrCSPs were structurally conserved and responsive to the abiotic stresses, such as cold, high osmotic, and abscisic acid (ABA) treatments. PbrCSP1, which is specifically expressed in pear pollen tubes, was selected for further research. PbrCSP1 was localized in both the cytoplasm and nucleus. Suppressing the expression of PbrCSP1 significantly inhibited the pollen tube growth in vitro. Conversely, overexpression of PbrCSP1 promoted the growth of pear pollen tubes under the normal condition and, notably, under the cold environment at 4 °C. These findings highlight an essential role of PbrCSP1 in facilitating the normal growth and enhancing cold resistance in pear pollen tubes.

中文翻译：

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PbrCSP1是一种花粉管特异性冷休克结构域蛋白，对于梨花粉管的生长和耐寒性至关重要

摘要

冷休克结构域蛋白（CSP）最初在大肠杆菌中发现，已被证明在耐寒性中发挥积极作用。先前对小麦、水稻和拟南芥的研究表明，CSP 在细菌和高等植物的耐寒性中具有功能保守性。然而，梨花粉管代表了对低温高度敏感的脆弱生殖器官，PbrCSPs 在梨花粉管中的生物学功能仍然很大程度上未知。在本研究中，在 7 个蔷薇科物种中总共鉴定了 22 个 CSP，重点是梨 ( Pyrus bretschneideri Rehder) 中的 4 个 PbrCSP 的特征。所有四种 PbrCSP 在结构上都是保守的，并且对非生物胁迫有响应，例如冷、高渗透和脱落酸 (ABA) 处理。选择在梨花粉管中特异性表达的PbrCSP1进行进一步研究。PbrCSP1 定位于细胞质和细胞核。抑制PbrCSP1的表达可显着抑制体外花粉管的生长。相反，在正常条件下，特别是在4℃的寒冷环境下， PbrCSP1的过表达促进了梨花粉管的生长。这些发现强调了 PbrCSP1 在促进梨花粉管正常生长和增强耐寒性方面的重要作用。