State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China.
J Exp Bot. 2012 Oct;63(16):6003-16. doi: 10.1093/jxb/ers245. Epub 2012 Sep 20.
The heat shock response (HSR) induces the production of heat shock proteins (HSPs) through the activation of heat shock factors (HSF). HSF binding protein (HSBP) is reported to modulate the function of HSF by binding to their trimer and hence to regulate HSR. This report describes the role of OsHSBP1 and OsHSBP2 in the regulation of the HSR and seed development of rice. Both genes expressed ubiquitously in all tissues under normal growth conditions while their expression levels were significantly increased during recovery after heat shock treatment. Subcellular localization revealed the cytosol-nuclear localization of both OsHSBP1 and OsHSBP2 in onion epidermal cells. The yeast two-hybrid assay depicted the self-binding ability of both genes. Both genes were also important for seed development, as their knock-down lines were associated with significant seed abortion. The thermotolerance assay revealed that OsHSBP1 and OsHSBP2 are negative regulators of HSR and involved in acquired thermotolerance but not in basal thermotolerance since their over-expression transgenic lines pre-heated at sublethal temperature, showed significantly decreased seedling survival after heat shock treatment. Furthermore, antioxidant activity and gene expression of catalase and peroxidase was significantly increased in knock-down transgenic seedlings of OsHSBP1 and OsHSBP2 after heat stress compared with the wild type. The expression of heat specific HSPs was also increased significantly in knockdown line of both genes but in a specific manner, suggesting the involvement of HSBP genes in different pathways. Overall, the present study reveals the role of OsHSBP1 and OsHSBP2 in the regulation of the HSR and seed development of rice.
热休克反应 (HSR) 通过激活热休克因子 (HSF) 诱导热休克蛋白 (HSP) 的产生。据报道，热休克因子结合蛋白 (HSBP) 通过与三聚体结合来调节 HSF 的功能，从而调节 HSR。本报告描述了 OsHSBP1 和 OsHSBP2 在水稻 HSR 和种子发育中的作用。在正常生长条件下，这两个基因在所有组织中均广泛表达，而在热休克处理后恢复期间，其表达水平显著增加。亚细胞定位显示 OsHSBP1 和 OsHSBP2 在洋葱表皮细胞中的细胞质-核定位。酵母双杂交试验描述了这两个基因的自我结合能力。这两个基因对于种子发育也很重要，因为它们的敲低系与明显的种子败育有关。耐热性试验表明，OsHSBP1 和 OsHSBP2 是 HSR 的负调节剂，参与获得性耐热性，但不参与基础耐热性，因为它们的过表达转基因系在亚致死温度下预热后，在热休克处理后幼苗存活率显著降低。此外，与野生型相比，OsHSBP1 和 OsHSBP2 的敲低转基因幼苗在热应激后过氧化氢酶和过氧化物酶的抗氧化活性和基因表达显著增加。敲低这两个基因的表达特异性 HSPs 的表达也显著增加，但方式不同，表明 HSBP 基因参与了不同的途径。总的来说，本研究揭示了 OsHSBP1 和 OsHSBP2 在调节水稻 HSR 和种子发育中的作用。
