植物RETINOBLASTOMA-RELATED (RBR)蛋白网络调控根尖干细胞损伤修复的分子机制

植物通过调节其生长发育和抗性响应，以应对外界环境中的生物与非生物胁迫。根的生长依赖于根尖干细胞的持续分裂活性。根干细胞如何响应环境信号并对损伤进行修复以调控根的适应性生长？我们运用激光切除根尖干细胞和部分切除根尖分生组织的方法诱导干细胞进行损伤修复，发现了损伤诱导的茉莉酸途径调控根尖干细胞损伤修复的分子调控网络。植物RBR(RETINOBLASTOMA-RELATED)蛋白是视网膜神经胶质瘤易感蛋白RB的同源蛋白，其位于该分子调控网络的下游。然而我们对RBR调控根尖干细胞损伤修复的分子机制仍然不清楚。本项目前期发现RBR保守位点突变造成损伤修复缺陷，我们拟通过筛选RBR保守位点的互作蛋白，结合细胞，遗传，生化等手段探索互作生物学意义，进一步解析RBR蛋白网络调控根尖干细胞损伤修复的分子机理，从而更好的了解植物是如何平衡生长发育和抗性响应之间的关系，也将为作物根系的改良和育种提供理论基础。

Plants are sessile and have to respond to environmental challenges by reallocating resources between growth, response to biotic/abiotic stress, and defense. Root growth and development relies on the continuous division activity of stem cells in the root apical meristem. It remains an open question how root stem cells respond to environmental signals, and repair wounding/damage tissues to regulate the adaptive growth of roots. In previous studies, we performed laser ablation of root stem cell niche and partial resection of root apical meristem to induce wound healing and wounding induced regeneration, and we reveal a jasmonate signaling network which activates the root stem cells and promotes wound healing and regeneration. In addition, we reveal that the conserved RBR (RETINOBLASTOMA-RELATED) protein, plant homolog of the human tumor suppressor Retinoblastoma (RB) protein, is downstream of this molecular network. Nevertheless, the molecular mechanism of RBR in root stem cell wound healing remains elusive. Our recent studies reveal that point mutation of RBR (RBRn849f, Asn to Phe, conserved between plants and animals) leads to severe wound healing defect in root stem cells. In this project, we plan to combine cell biology, genetics, molecular biology and biochemistry, to screen for RBR interacting proteins through the RBRn849 conserved site, and reveal the biological function and molecular mechanisms of root stem cell wound healing by RBR and its interaction proteins. With this aim, we can better understand how plants balance growth and development with stress responses. It will also provide resources and theoretical basis for crop root improvement and breeding.