Mechanosensitive ion channels are essential for sensing and converting mechanical forces into electrical or chemical signals.These channels are widely distributed across bacteria,animals,and plants.In Arabidopsis thal...Mechanosensitive ion channels are essential for sensing and converting mechanical forces into electrical or chemical signals.These channels are widely distributed across bacteria,animals,and plants.In Arabidopsis thaliana,the OSCA family has been identified as mechanically activated ion channels that respond to osmotic stress by allowing calcium ions to enter the cell.This influx increases the cytoplasmic calcium concentration,triggering osmotic stress-induced signal transduction cascades in plants.In this study,we determined the structures of OSCA2.2 and OSCA3.1 via cryoelectron microscopy(cryo-EM).Both proteins form homodimers consisting of 11 transmembrane helices(TM1–11).The ion conduction pathway is formed by TM4–8.Despite belonging to the same family,OSCA2.2 and OSCA3.1 exhibit notable structural variations.Structural analysis revealed that both OSCA2.2 and OSCA3.1 exhibit a closed conformation.We also conducted functional studies on OSCA proteins via electrophysiological experiments and confirmed the role of key amino acids in the process of ion permeation.展开更多
Background:Cotton(Gossypium hirsutum) provides the largest natural fiber for the textile manufacturing industries,but its production is on the decline due to the effects of salinity.Soil salt-alkalization leads to dam...Background:Cotton(Gossypium hirsutum) provides the largest natural fiber for the textile manufacturing industries,but its production is on the decline due to the effects of salinity.Soil salt-alkalization leads to damage in cotton growth and a decrease in yields.Hyperosmolality-gated calcium-permeable channels(OSCA) have been found to be involved in the detection of extracellular changes which trigger an increase in cytosolic free calcium concentration.Hyperosmolality-induced calcium ion increases have been widely speculated to be playing a role in osmosensing in plants.However,the molecular nature of the corresponding calcium ion channels remains unclearly.In this research work,we describe the OSCA genes and their putative function in osmosensing in plants by carrying out genomewide identification,characterization and functional analysis of the significantly up-regulated OSCA gene,GhOSCA1.1 through reverse genetics.Result:A total of 35,21 and 22 OSCA genes were identified in G.hirsutum,G.arboreum,and G.raimondii genomes,respectively,and were classified into four different clades according to their gene structure and phylogenetic relationship.Gene and protein structure analysis indicated that 35 GhOSCA genes contained a conserved RSN17 TM(PF02714) domain.Moreover,the cis-regulatory element analysis indicated that the OSCA genes were involved in response to abiotic stress.Furthermore,the knockdown of one of the highly up-regulated genes,GhOSCA1.1 showed that the virus-induced gene silenced(VIGS) plants were highly sensitive to dehydration and salinity stresses compared with the none VIGS plants as evident with higher concentration levels of oxidant enzymes compared with the antioxidant enzymes on the leaves of the stressed plants.Conclusion:This study provides the first systematic analysis of the OSCA gene family and will be important for understanding the putative functions of the proteins encoded by the OSCA genes in cotton.These results provide a new insight of defense responses in general and lay the foundation for further investigation of the molecular role played by the OSCA genes,thereby providing suitable approaches to improve crop performance under salinity and drought stress conditions.展开更多
基金supported by the National Natural Science Foundation of China(32322041,W2412029,32321001,32471279)USTC Research Funds of the Double First-Class Initiative(YD9100002004,YD9100002020)+2 种基金Fundamental Research Funds for the Central Universities(WK9100000031)Research Funds of Center for Advanced Interdisciplinary Science and Biomedicine of IHM(QYPY20230034)the Natural Science Foundation of Anhui Province(2408085JX005).
文摘Mechanosensitive ion channels are essential for sensing and converting mechanical forces into electrical or chemical signals.These channels are widely distributed across bacteria,animals,and plants.In Arabidopsis thaliana,the OSCA family has been identified as mechanically activated ion channels that respond to osmotic stress by allowing calcium ions to enter the cell.This influx increases the cytoplasmic calcium concentration,triggering osmotic stress-induced signal transduction cascades in plants.In this study,we determined the structures of OSCA2.2 and OSCA3.1 via cryoelectron microscopy(cryo-EM).Both proteins form homodimers consisting of 11 transmembrane helices(TM1–11).The ion conduction pathway is formed by TM4–8.Despite belonging to the same family,OSCA2.2 and OSCA3.1 exhibit notable structural variations.Structural analysis revealed that both OSCA2.2 and OSCA3.1 exhibit a closed conformation.We also conducted functional studies on OSCA proteins via electrophysiological experiments and confirmed the role of key amino acids in the process of ion permeation.
基金funded by the National Natural Science Foundation of China(31530053/31621005)the National Key R&D Program(2016YFD0101401/2017YFD0101601)
文摘Background:Cotton(Gossypium hirsutum) provides the largest natural fiber for the textile manufacturing industries,but its production is on the decline due to the effects of salinity.Soil salt-alkalization leads to damage in cotton growth and a decrease in yields.Hyperosmolality-gated calcium-permeable channels(OSCA) have been found to be involved in the detection of extracellular changes which trigger an increase in cytosolic free calcium concentration.Hyperosmolality-induced calcium ion increases have been widely speculated to be playing a role in osmosensing in plants.However,the molecular nature of the corresponding calcium ion channels remains unclearly.In this research work,we describe the OSCA genes and their putative function in osmosensing in plants by carrying out genomewide identification,characterization and functional analysis of the significantly up-regulated OSCA gene,GhOSCA1.1 through reverse genetics.Result:A total of 35,21 and 22 OSCA genes were identified in G.hirsutum,G.arboreum,and G.raimondii genomes,respectively,and were classified into four different clades according to their gene structure and phylogenetic relationship.Gene and protein structure analysis indicated that 35 GhOSCA genes contained a conserved RSN17 TM(PF02714) domain.Moreover,the cis-regulatory element analysis indicated that the OSCA genes were involved in response to abiotic stress.Furthermore,the knockdown of one of the highly up-regulated genes,GhOSCA1.1 showed that the virus-induced gene silenced(VIGS) plants were highly sensitive to dehydration and salinity stresses compared with the none VIGS plants as evident with higher concentration levels of oxidant enzymes compared with the antioxidant enzymes on the leaves of the stressed plants.Conclusion:This study provides the first systematic analysis of the OSCA gene family and will be important for understanding the putative functions of the proteins encoded by the OSCA genes in cotton.These results provide a new insight of defense responses in general and lay the foundation for further investigation of the molecular role played by the OSCA genes,thereby providing suitable approaches to improve crop performance under salinity and drought stress conditions.
