The anatomy of the root caps in four root types of Avicennia marina were studied using conventional histological techniques by Ligth Microscopy (LM) in order to relate their development and structure of their function...The anatomy of the root caps in four root types of Avicennia marina were studied using conventional histological techniques by Ligth Microscopy (LM) in order to relate their development and structure of their function as environmental adaptation in mangrove’s root and to identify cellular polarities with respect to gravity. In columella cells, nuclei are located proximally. The result reveals that root caps consisted of two regions, i.e., central columella or statenchyma and peripheral regions. The columella cells (statocyte) are in the form of oval to rectangular. We also found that all root with marked gravitropism have statoliths that settle along different walls of that statocyte. Caps vary in form and size within root system of A. marina. The most striking feature of the root is the distinct and extensive root cap with quite long files of cells. From its shape, structure, and location, it seems clear that the root caps protects the cells under it from abrasion and assists the root in penetrating the soil.展开更多
Root cap not only protects root meristem,but also detects and transduces the signals of environmental changes to affect root development.The symplastic communication is an important way for plants to transduce signals...Root cap not only protects root meristem,but also detects and transduces the signals of environmental changes to affect root development.The symplastic communication is an important way for plants to transduce signals to coordinate the development and physiology in response to the changing enviroments.However,it is unclear how the symplastic communication between root cap cells affects root growth.Here we exploit an inducible system to specifically block the symplastic communication in the root cap.Transient blockage of plasmodesmata(PD)in differentiated collumella cells severely impairs the root development in Arabidopsis,in particular in the stem cell niche and the proximal meristem.The neighboring stem cell niche is the region that is most sensitive to the disrupted symplastic communication and responds rapidly via the alteration of auxin distribution.In the later stage,the cell division in proximal meristem is inhibited,presumably due to the reduced auxin level in the root cap.Our results reveal the essential role of the differentiated collumella cells in the root cap mediated signaling system that directs root development.展开更多
Rapid climate change has led to enhanced soil salinity,one of the major determinants of land degradation,resulting in low agricultural productivity.This has a strong negative impact on food security and environmental ...Rapid climate change has led to enhanced soil salinity,one of the major determinants of land degradation,resulting in low agricultural productivity.This has a strong negative impact on food security and environmental sustainability.Plants display various physiological,developmental,and cellular responses to deal with salt stress.Recent studies have highlighted the root cap as the primary stress sensor and revealed its crucial role in halotropism.The root cap covers the primary root meristem and is the first cell type to sense and respond to soil salinity,relaying the signal to neighboring cell types.However,it remains unclear how root-cap cells perceive salt stress and contribute to the salt-stress response.Here,we performed a root-cap cell-specific proteomics study to identify changes in the proteome caused by salt stress.The study revealed a very specific salt-stress response pattern in root-cap cells compared with non-rootcap cells and identified several novel proteins unique to the root cap.Root-cap-specific protein–protein interaction(PPI)networks derived by superimposing proteomics data onto known global PPI networks revealed that the endoplasmic reticulum(ER)stress pathway is specifically activated in root-cap cells upon salt stress.Importantly,we identified root-cap-specific jacalin-associated lectins(JALs)expressed in response to salt stress.A JAL10-GFP fusion protein was shown to be localized to the ER.Analysis of jal10 mutants indicated a role for JAL10 in regulating the ER stress pathway in response to salt.Taken together,our findings highlight the participation of specific root-cap proteins in salt-stress response pathways.Furthermore,root-cap-specific JAL proteins and their role in the salt-mediated ER stress pathway open a new avenue for exploring tolerance mechanisms and devising better strategies to increase plant salinity tolerance and enhance agricultural productivity.展开更多
GRIP domain proteins, locating to the trans-Golgi network, are thought to play an essential role in Golgi apparatus trafficking in yeast and animal cells. In the present study, AtGRIP cDNA was amplified by reverse tra...GRIP domain proteins, locating to the trans-Golgi network, are thought to play an essential role in Golgi apparatus trafficking in yeast and animal cells. In the present study, AtGRIP cDNA was amplified by reverse transcriptase PCR from RNA isolated from Arabidopsis seedling. The GST fusion protein of AtGRIP was affinity-purified and its rabbit polyclonal antibody was obtained. Immuno-blotting with the purified anti-AtGRIP polyclonal antibody demonstrated that the molecular mass of AtGRIP protein is about 92 kD, and its expression is not tissue-specific in Arabidopsis. Immunoflourescent labeling and confocal microscopy revealed that the AtGRIP protein was co-localized with Golgi stacks in Arabidopsis root cells. Immuno-gold labeling and electron microscopy observation showed that AtGRIP protein was mainly located to the membrane of the secretory vesicles of trans-Golgi network in Arabidopsis root cap cells. Taken together, these results indicate that the localization of GRIP domain proteins between plants and animal cells are conserved. These results also suggest that the AtGRIP may be involved in regulating the formation or sorting of Golgi-associated vesicles in plant cells.展开更多
Soybean is an important upland crop,but its productivity is often limited by anaerobic stress caused by waterlogging.The ability to adjust root growth under environmental constraints is an important physiological trai...Soybean is an important upland crop,but its productivity is often limited by anaerobic stress caused by waterlogging.The ability to adjust root growth under environmental constraints is an important physiological trait for adapting to an everchanging environment,and root pruning is an artificial technique for regenerating the root system.In the present study,we investigated whether root pruning in soybean can effectively alleviate the inhibitory effects of anaerobic stress.Soybean plants were affected by anaerobic stress at the germination,vegetative stage 1(V1),and reproductive stage 1(R1)stages,and then the plants were treated with root pruning just after the stress treatment.Soybean plants at the germination stage were treated with root cap and tip removals after hypoxia(N_(2)treatment).Root cap removal was more effective in suppressing the inhibitory effects of hypoxia than root tip removal(5 mm from the tip).The shoot dry weights of the soybean plants with and without root cap removal after hypoxia were 51.2 and 73.8%of the control,respectively,while the root dry weights of plants with and without root cap removal after hypoxia were 43.2 and 62.8%of the control,respectively.As root cap removal effectively enhanced soybean growth after anaerobic stress,the root cap may be the candidate tissue for the stress memory mechanism.When soybean plants at the V1 stage of growth were affected by anaerobic stress,the branch number,pod weight in the main stem,root length,and root surface area of the soybean plants treated with anaerobic stress at the R1 stage significantly decreased compared with those of the control.In contrast,root pruning(2 mm from the tip)immediately after the stress treatment enhanced root growth,branch number,and pod weight.The branch number,pod weight,root length,and root surface area of the plants treated with root pruning were 1.13,1.14,1.12,and 1.13 times higher than those of plants treated with anaerobic stress.Plasmolysis was observed in the root meristem,columella,and cortical cells in soybean roots subjected to anaerobic conditions.However,damage was not observed in the newly emerged roots after root pruning in plants treated with anaerobic stress.These results suggested that root pruning is effective in enhancing soybean growth after anaerobic stress.This effectiveness may be due to the regeneration and elongation of healthy lateral roots during the recovery period.When soybean plants were affected by anaerobic stress at the R1 stage,root pruning just after the stress treatment was ineffective.Thus,suppressing the growth reduction due to anaerobic stress at reproductive stages using only root pruning may be difficult.展开更多
文摘The anatomy of the root caps in four root types of Avicennia marina were studied using conventional histological techniques by Ligth Microscopy (LM) in order to relate their development and structure of their function as environmental adaptation in mangrove’s root and to identify cellular polarities with respect to gravity. In columella cells, nuclei are located proximally. The result reveals that root caps consisted of two regions, i.e., central columella or statenchyma and peripheral regions. The columella cells (statocyte) are in the form of oval to rectangular. We also found that all root with marked gravitropism have statoliths that settle along different walls of that statocyte. Caps vary in form and size within root system of A. marina. The most striking feature of the root is the distinct and extensive root cap with quite long files of cells. From its shape, structure, and location, it seems clear that the root caps protects the cells under it from abrasion and assists the root in penetrating the soil.
基金This work is supported by the National Key Research and Development Program of China(2018YFD1000800)the grant from the National Natural Science Foundation of China(31900169).
文摘Root cap not only protects root meristem,but also detects and transduces the signals of environmental changes to affect root development.The symplastic communication is an important way for plants to transduce signals to coordinate the development and physiology in response to the changing enviroments.However,it is unclear how the symplastic communication between root cap cells affects root growth.Here we exploit an inducible system to specifically block the symplastic communication in the root cap.Transient blockage of plasmodesmata(PD)in differentiated collumella cells severely impairs the root development in Arabidopsis,in particular in the stem cell niche and the proximal meristem.The neighboring stem cell niche is the region that is most sensitive to the disrupted symplastic communication and responds rapidly via the alteration of auxin distribution.In the later stage,the cell division in proximal meristem is inhibited,presumably due to the reduced auxin level in the root cap.Our results reveal the essential role of the differentiated collumella cells in the root cap mediated signaling system that directs root development.
基金supported by IISER Tirupati and by an Early Career Research award from the Science and Engineering Research Board,Department of Science and Technology,Govt.of India(ECR/2016/001071)to E.R.K.K.D.acknowledges the CSIR-JRF fellowship and Bi-nationally supervised doctoral degree scholarship from DAAD(91730390)for her PhD.A.M.and A.P.G.acknowledge funding from IISER Tirupati for graduate studies.S.C.acknowledges funding from IISER Tirupati and the Ramalingaswami Re-entry Fellowship(BT/RLF/Re-entry/05/2018)Department of Biotechnology,Government of India.
文摘Rapid climate change has led to enhanced soil salinity,one of the major determinants of land degradation,resulting in low agricultural productivity.This has a strong negative impact on food security and environmental sustainability.Plants display various physiological,developmental,and cellular responses to deal with salt stress.Recent studies have highlighted the root cap as the primary stress sensor and revealed its crucial role in halotropism.The root cap covers the primary root meristem and is the first cell type to sense and respond to soil salinity,relaying the signal to neighboring cell types.However,it remains unclear how root-cap cells perceive salt stress and contribute to the salt-stress response.Here,we performed a root-cap cell-specific proteomics study to identify changes in the proteome caused by salt stress.The study revealed a very specific salt-stress response pattern in root-cap cells compared with non-rootcap cells and identified several novel proteins unique to the root cap.Root-cap-specific protein–protein interaction(PPI)networks derived by superimposing proteomics data onto known global PPI networks revealed that the endoplasmic reticulum(ER)stress pathway is specifically activated in root-cap cells upon salt stress.Importantly,we identified root-cap-specific jacalin-associated lectins(JALs)expressed in response to salt stress.A JAL10-GFP fusion protein was shown to be localized to the ER.Analysis of jal10 mutants indicated a role for JAL10 in regulating the ER stress pathway in response to salt.Taken together,our findings highlight the participation of specific root-cap proteins in salt-stress response pathways.Furthermore,root-cap-specific JAL proteins and their role in the salt-mediated ER stress pathway open a new avenue for exploring tolerance mechanisms and devising better strategies to increase plant salinity tolerance and enhance agricultural productivity.
基金the National Natural Science Foundation of China (Grant Nos. 30570924 and 30721062)
文摘GRIP domain proteins, locating to the trans-Golgi network, are thought to play an essential role in Golgi apparatus trafficking in yeast and animal cells. In the present study, AtGRIP cDNA was amplified by reverse transcriptase PCR from RNA isolated from Arabidopsis seedling. The GST fusion protein of AtGRIP was affinity-purified and its rabbit polyclonal antibody was obtained. Immuno-blotting with the purified anti-AtGRIP polyclonal antibody demonstrated that the molecular mass of AtGRIP protein is about 92 kD, and its expression is not tissue-specific in Arabidopsis. Immunoflourescent labeling and confocal microscopy revealed that the AtGRIP protein was co-localized with Golgi stacks in Arabidopsis root cells. Immuno-gold labeling and electron microscopy observation showed that AtGRIP protein was mainly located to the membrane of the secretory vesicles of trans-Golgi network in Arabidopsis root cap cells. Taken together, these results indicate that the localization of GRIP domain proteins between plants and animal cells are conserved. These results also suggest that the AtGRIP may be involved in regulating the formation or sorting of Golgi-associated vesicles in plant cells.
基金supported by the Japan Society for the Promotion of Science(JSPS)KAKENHI(JP20K06003 to M.I.)。
文摘Soybean is an important upland crop,but its productivity is often limited by anaerobic stress caused by waterlogging.The ability to adjust root growth under environmental constraints is an important physiological trait for adapting to an everchanging environment,and root pruning is an artificial technique for regenerating the root system.In the present study,we investigated whether root pruning in soybean can effectively alleviate the inhibitory effects of anaerobic stress.Soybean plants were affected by anaerobic stress at the germination,vegetative stage 1(V1),and reproductive stage 1(R1)stages,and then the plants were treated with root pruning just after the stress treatment.Soybean plants at the germination stage were treated with root cap and tip removals after hypoxia(N_(2)treatment).Root cap removal was more effective in suppressing the inhibitory effects of hypoxia than root tip removal(5 mm from the tip).The shoot dry weights of the soybean plants with and without root cap removal after hypoxia were 51.2 and 73.8%of the control,respectively,while the root dry weights of plants with and without root cap removal after hypoxia were 43.2 and 62.8%of the control,respectively.As root cap removal effectively enhanced soybean growth after anaerobic stress,the root cap may be the candidate tissue for the stress memory mechanism.When soybean plants at the V1 stage of growth were affected by anaerobic stress,the branch number,pod weight in the main stem,root length,and root surface area of the soybean plants treated with anaerobic stress at the R1 stage significantly decreased compared with those of the control.In contrast,root pruning(2 mm from the tip)immediately after the stress treatment enhanced root growth,branch number,and pod weight.The branch number,pod weight,root length,and root surface area of the plants treated with root pruning were 1.13,1.14,1.12,and 1.13 times higher than those of plants treated with anaerobic stress.Plasmolysis was observed in the root meristem,columella,and cortical cells in soybean roots subjected to anaerobic conditions.However,damage was not observed in the newly emerged roots after root pruning in plants treated with anaerobic stress.These results suggested that root pruning is effective in enhancing soybean growth after anaerobic stress.This effectiveness may be due to the regeneration and elongation of healthy lateral roots during the recovery period.When soybean plants were affected by anaerobic stress at the R1 stage,root pruning just after the stress treatment was ineffective.Thus,suppressing the growth reduction due to anaerobic stress at reproductive stages using only root pruning may be difficult.
