National Institute of Plant Genome Research, Jawaharlal Nehru University Campus, Aruna Asaf Ali Marg, New Delhi-110067, India.
Sci Rep. 2016 Dec 9;6:38121. doi: 10.1038/srep38121.
Tubby and Tubby-like proteins (TLPs), in mammals, play critical roles in neural development, while its function in plants is largely unknown. We previously demonstrated that the chickpea TLP, CaTLP1, participates in osmotic stress response and might be associated with ABA-dependent network. However, how CaTLP1 is connected to ABA signaling remains unclear. The CaTLP1 was found to be engaged in ABA-mediated gene expression and stomatal closure. Complementation of the yeast yap1 mutant with CaTLP1 revealed its role in ROS scavenging. Furthermore, complementation of Arabidopsis attlp2 mutant displayed enhanced stress tolerance, indicating the functional conservation of TLPs across the species. The presence of ABA-responsive element along with other motifs in the proximal promoter regions of TLPs firmly established their involvement in stress signalling pathways. The CaTLP1 promoter driven GUS expression was restricted to the vegetative organs, especially stem and rosette leaves. Global protein expression profiling of wild-type, attlp2 and complemented Arabidopsis plants revealed 95 differentially expressed proteins, presumably involved in maintaining physiological and biological processes under dehydration. Immunoprecipitation assay revealed that protein kinases are most likely to interact with CaTLP1. This study provides the first demonstration that the TLPs act as module for ABA-mediated stomatal closure possibly via interaction with protein kinase.
豌豆科块茎蛋白（Tubby and Tubby-like proteins，TLPs）在哺乳动物中发挥着重要作用，参与神经发育，但其在植物中的功能尚不清楚。我们之前的研究表明，鹰嘴豆 TLP（CaTLP1）参与渗透胁迫响应，可能与 ABA 依赖的信号网络有关。然而，CaTLP1 如何与 ABA 信号相关联仍不清楚。我们发现 CaTLP1 参与 ABA 介导的基因表达和气孔关闭。用 CaTLP1 补充酵母 yap1 突变体显示其在 ROS 清除中的作用。此外，对拟南芥 attlp2 突变体的互补显示出增强的胁迫耐受性，表明 TLPs 在物种间具有功能保守性。TLPs 近端启动子区域存在 ABA 反应元件以及其他基序，这就确定了它们参与胁迫信号通路。CaTLP1 启动子驱动的 GUS 表达局限于营养器官，特别是茎和莲座叶。野生型、atttlp2 和互补型拟南芥植物的全局蛋白质表达谱分析显示，有 95 种差异表达蛋白，可能参与在脱水条件下维持生理和生物过程。免疫沉淀实验表明，蛋白激酶可能与 CaTLP1 相互作用。本研究首次证明 TLPs 作为 ABA 介导的气孔关闭的模块，可能通过与蛋白激酶的相互作用来实现。
