Ionic polymer-metal composite （IPMC） is a type of electroactive polymer （EAP）. In this paper, based on Nemat-Nasser model, an improved model is developed to explain the initial nonlinear response of electric actua...Ionic polymer-metal composite （IPMC） is a type of electroactive polymer （EAP）. In this paper, based on Nemat-Nasser model, an improved model is developed to explain the initial nonlinear response of electric actuation on the fixed end deformation. Three IPMC strip samples with different surface resistance are chosen for analysis. Further, from simulation and experiment results, it is found that the root deformation made the tip movement of the IPMC strip with little surface resistance, but this effect was less and less when the surface resistance reduced. The calculation results of this model for the fixed end show a more accurate simulation for the actual deformation of IPMC strips.展开更多
The formation of nitrogen-fixing no dules on legume roots requires the coordination of infection by rhizobia at the root epidermis with the initiation of cell divisions in the root cortex.During infection,rhizobia att...The formation of nitrogen-fixing no dules on legume roots requires the coordination of infection by rhizobia at the root epidermis with the initiation of cell divisions in the root cortex.During infection,rhizobia attach to the tip of elongating root hairs which then curl to entrap the rhizobia.However,the mechanism of root hair deformation and curling in response to symbiotic signals is still elusive.Here,we found that small GTPases(MtRac1/MtROP9 and its homologs)are required for root hair development and rhizobial infection in Medicago truncatula.Our results show that the Nod factor receptor LYK3 phosphorylates the guanine nucleotide exchange factor MtRopGEF2 at S73 which is critical for the polar growth of root hairs.In turn,phosphorylated MtRopGEF2 can activate MtRac1.Activated MtRac1 was found to localize at the tips of root hairs and to strongly interact with LYK3 and NFP.Taken together,our results support the hypothesis that MtRac1,LYK3,and NFP form a polarly localized receptor complex that regulates root hair deformation during rhizobial infection.展开更多
基金Funded by the National Natural Science Foundation of China(Nos.50735002,50875123,and 90816003)the 111 Project(No.B12021)
文摘Ionic polymer-metal composite （IPMC） is a type of electroactive polymer （EAP）. In this paper, based on Nemat-Nasser model, an improved model is developed to explain the initial nonlinear response of electric actuation on the fixed end deformation. Three IPMC strip samples with different surface resistance are chosen for analysis. Further, from simulation and experiment results, it is found that the root deformation made the tip movement of the IPMC strip with little surface resistance, but this effect was less and less when the surface resistance reduced. The calculation results of this model for the fixed end show a more accurate simulation for the actual deformation of IPMC strips.
基金This work was supported by the National Key Research and Development Program of China(2016YFA0500502)the National Science Foundation(31825003,31730103,31870218)+1 种基金the Strategic Priority Research Program"Molecular Mechanism of Plant Growth and Development"of the Chinese Academy of Sciences(XDB27040207)CAS Project for Young Scientists in Basic Research(YSBR-011).
文摘The formation of nitrogen-fixing no dules on legume roots requires the coordination of infection by rhizobia at the root epidermis with the initiation of cell divisions in the root cortex.During infection,rhizobia attach to the tip of elongating root hairs which then curl to entrap the rhizobia.However,the mechanism of root hair deformation and curling in response to symbiotic signals is still elusive.Here,we found that small GTPases(MtRac1/MtROP9 and its homologs)are required for root hair development and rhizobial infection in Medicago truncatula.Our results show that the Nod factor receptor LYK3 phosphorylates the guanine nucleotide exchange factor MtRopGEF2 at S73 which is critical for the polar growth of root hairs.In turn,phosphorylated MtRopGEF2 can activate MtRac1.Activated MtRac1 was found to localize at the tips of root hairs and to strongly interact with LYK3 and NFP.Taken together,our results support the hypothesis that MtRac1,LYK3,and NFP form a polarly localized receptor complex that regulates root hair deformation during rhizobial infection.
