Plants employ multifaceted mechanisms to fight with numerous pathogens in nature. Resistance （R） genes are the most effective weapons against pathogen invasion since they can specifically recognize the corresponding...Plants employ multifaceted mechanisms to fight with numerous pathogens in nature. Resistance （R） genes are the most effective weapons against pathogen invasion since they can specifically recognize the corresponding pathogen effectors or associated protein（s） to activate plant immune responses at the site of infection. Up to date, over 70 R genes have been isolated from various plant species. Most R proteins contain conserved motifs such as nucleotide-binding site （NBS）, leucine-rich repeat （LRR）, Toll-interleukin-1 receptor domain （TIR, homologous to cytoplasmic domains of the Drosophila Toll protein and the manamalian intefleukin-1 receptor）, coiled-coil （CC） or leucine zipper （LZ） structure and protein kinase domain （PK）. Recent results indicate that these domains play significant roles in R protein interactions with effector proteins from pathogens and in activating signal transduction pathways involved in innate immunity. This review highlights an overview of the recent progress in elucidating the structure, function and evolution of the isolated R genes in different plant-pathogen interaction systems.展开更多
We have developed a cell-free system that can trigger the nuclei purified from mouse liver and suspensioncultured carrot cells to undergo apoptosis as defined by the formation of apoptotic bodies and nucleosomal DNA f...We have developed a cell-free system that can trigger the nuclei purified from mouse liver and suspensioncultured carrot cells to undergo apoptosis as defined by the formation of apoptotic bodies and nucleosomal DNA fragments. The effects of different divalent cations and cycloheximide on DNA cleavage in this system were assessed.The fact that nuclei of plant cells can be induced to undergo apoptosis in a cell-free animal system suggests that animals and plants share a common signal transduction pathway triggering in the initiation stage of apoptosis.展开更多
Nitrogen is an essential macronutrient in plant growth and development. Ammonium is one of the major inorganic nitrogen forms for root uptake. The homeostasis of ammonium in the plant cell is under tight control to pr...Nitrogen is an essential macronutrient in plant growth and development. Ammonium is one of the major inorganic nitrogen forms for root uptake. The homeostasis of ammonium in the plant cell is under tight control to prevent ammonium toxicity when in excess. In the ammonium sig- naling pathway, internal and external ammonium can be de- tected by specific sensors, which in turn triggers a series of proper plant ammonium responses including transcription regulation and phosphorylation. Ammonium absorption is mainly mediated by the root-located ammonium transporters, which are key regulators in the nitrogen signaling pathway. Many researchers have attempted to unravel the mechanisms of ammonium uptake by the transporters. Fine-tuned modulation of ammonium homeostasis is necessary to main- tain an appropriate level of ammonium in the cytoplasm, which is a balance of ammonium efflux, assimilation and compartmentation. Recently, there has been important pro- gress in revealing the ammonium sensing and signaling mechanisms. In this review, we focus on the homeostatic regulation and signaling of cytosolic ammonium.展开更多
基金This work was supported by grants from the Natural Science Foundation of China (No. 30470990, No. 30571063)the"948"Project from the Minister of Agriculture in China, the"973"Project from the Minister of Science and Technology (No.2006CB101904)+1 种基金Hunan Natural Science Foundation (No.06JJ10006)Scientific Research Fund of Hunan Provincial Education department (No.04A024).
文摘Plants employ multifaceted mechanisms to fight with numerous pathogens in nature. Resistance （R） genes are the most effective weapons against pathogen invasion since they can specifically recognize the corresponding pathogen effectors or associated protein（s） to activate plant immune responses at the site of infection. Up to date, over 70 R genes have been isolated from various plant species. Most R proteins contain conserved motifs such as nucleotide-binding site （NBS）, leucine-rich repeat （LRR）, Toll-interleukin-1 receptor domain （TIR, homologous to cytoplasmic domains of the Drosophila Toll protein and the manamalian intefleukin-1 receptor）, coiled-coil （CC） or leucine zipper （LZ） structure and protein kinase domain （PK）. Recent results indicate that these domains play significant roles in R protein interactions with effector proteins from pathogens and in activating signal transduction pathways involved in innate immunity. This review highlights an overview of the recent progress in elucidating the structure, function and evolution of the isolated R genes in different plant-pathogen interaction systems.
文摘We have developed a cell-free system that can trigger the nuclei purified from mouse liver and suspensioncultured carrot cells to undergo apoptosis as defined by the formation of apoptotic bodies and nucleosomal DNA fragments. The effects of different divalent cations and cycloheximide on DNA cleavage in this system were assessed.The fact that nuclei of plant cells can be induced to undergo apoptosis in a cell-free animal system suggests that animals and plants share a common signal transduction pathway triggering in the initiation stage of apoptosis.
基金supported by the National Key Basic Special Foundation of China(2012CB1143001)
文摘Nitrogen is an essential macronutrient in plant growth and development. Ammonium is one of the major inorganic nitrogen forms for root uptake. The homeostasis of ammonium in the plant cell is under tight control to prevent ammonium toxicity when in excess. In the ammonium sig- naling pathway, internal and external ammonium can be de- tected by specific sensors, which in turn triggers a series of proper plant ammonium responses including transcription regulation and phosphorylation. Ammonium absorption is mainly mediated by the root-located ammonium transporters, which are key regulators in the nitrogen signaling pathway. Many researchers have attempted to unravel the mechanisms of ammonium uptake by the transporters. Fine-tuned modulation of ammonium homeostasis is necessary to main- tain an appropriate level of ammonium in the cytoplasm, which is a balance of ammonium efflux, assimilation and compartmentation. Recently, there has been important pro- gress in revealing the ammonium sensing and signaling mechanisms. In this review, we focus on the homeostatic regulation and signaling of cytosolic ammonium.
