Membrane trafficking is essential for plant growth and responses to external signals.The plant unique FYVE domain-containing protein FREE1 is a component of the ESCRT complex（endosomal sorting complex required for tr...Membrane trafficking is essential for plant growth and responses to external signals.The plant unique FYVE domain-containing protein FREE1 is a component of the ESCRT complex（endosomal sorting complex required for transport）.FREE1 plays multiple roles in regulating protein trafficking and organelle biogenesis including the formation of intraluminal vesicles of multivesicular body（MVB）,vacuolar protein transport and vacuole biogenesis,and autophagic degradation.FREE1 knockout plants show defective MVB formation,abnormal vacuolar transport,fragmented vacuoles,accumulated autophagosomes,and seedling lethality.To further uncover the underlying mechanisms of FREE1 function in plants,we performed a forward genetic screen for mutants that suppressed the seedling lethal phenotype of FREE1-RNAi transgenic plants.The obtained mutants are termed as suppressors of free1（sof）.To date,229 putative sof mutants have been identified.Barely detecting of FREE1 protein with M3 plants further identified 84 FREE1-related suppressors.Also145 mutants showing no reduction of FREE1 protein were termed as RNAi-related mutants.Through next-generation sequencing（NGS）of bulked DNA from F2 mapping population of two RNAi-related sof mutants,FREE1-RNAi T-DNA inserted on chromosome 1 was identified and the causal mutation of putative sof mutant is being identified similarly.These FREE1-and RNAi-related sof mutants will be useful tools and resources for illustrating the underlying mechanisms of FREE1 function in intracellular trafficking and organelle biogenesis,as well as for uncovering the new components involved in the regulation of silencing pathways in plants.展开更多
A field under rice-wheat rotation was selected near Chengdu, China, to study thepopulation of Rhizoctonia solani anastomosis group 1 (AG-1), pathogen causing ricesheath blight disease, in natural soil ecosystem. Inocu...A field under rice-wheat rotation was selected near Chengdu, China, to study thepopulation of Rhizoctonia solani anastomosis group 1 (AG-1), pathogen causing ricesheath blight disease, in natural soil ecosystem. Inocula of the fungus recovered fromthe field were divided into three types, i.e., sclerotia, free mycelium retained in thesoil passed through a 0.355mm sieve, and colonized plant debris which was subdividedinto small colonized debris retained between 2.00 and 0.355mm sieves and large colonizeddebris retained on 2.00mm sieve after wet screening. Quantitative estimation of thethree types of inocula in one year indicated that small colonized debris was the dominantinoculum type for most of the time. The population peaked in March and September at 1210and 480 colonized debris 100g-1 air-dry soil respectively, and fell down in December andAugust to 0 and 177 colonized debris 100g-1 air-dry soil respectively. Free mycelium wasonly detectable in March, September and October with 1209, 7.9 and 14.5g fresh wtmyceliumg-1 air-dry soil respectively, which corresponded to the two peaks and the secondhighest level of small debris density in the year. Viable sclerotia and large colonizeddebris were rare with populations ranging from 0 to 3 for sclerotia and 0 to 14 for largecolonized debris 100g-1 air-dry soil, but were the main structures to survive overwinter. It was expected that soil temperature was the main factor determining populationdynamics of R.solani AG-1 in natural soil. Optimum temperature for population increasingis predicted to be around 15℃, with a range from 10 to 25℃. Viability tests indicatedthat 60.9% sclerotia could survive after 265d being buried in natural sandy loam in fieldconditions in Beijing, while colonized rice straw debris (0.5-1.0cm long) could notyield the fungus on medium plates after 88d of being buried under the same conditions.展开更多
Calcium homeostasis in synaptosomes is altered during aging. The intrasynaptomal free calcium concentration ([Ca2+]i) was determined in 3- and 24-month-old rats treated with or without Rbl and Rgl. As expected, the [C...Calcium homeostasis in synaptosomes is altered during aging. The intrasynaptomal free calcium concentration ([Ca2+]i) was determined in 3- and 24-month-old rats treated with or without Rbl and Rgl. As expected, the [Ca2-]i level increased with age. Treatment with Rbl and Rgl elicited an obvious decrease of [Ca2+]i content, especially in aged rates. In addition, Rbl and Rgl significantly stimulated the activity of Na+, K+-ATPase while Rbl inhibited the activity of Ca2+, Mg2--ATPase arid calmodulin. In view of the close relationship of [Ca2-]i level with aging, the changes of [Ca2+]i induced by Rbl and Rgl, as shown by our results, might provide an explanation of the mechanisms of their antiaging function.展开更多
基金supported by grants from the NIH GM114660 to Y.Zhaothe Research Grants Council of Hong Kong (CUHK466011,465112,466613,CUHK2/CRF/11G,C401114R and Ao E/M-05/12)+2 种基金NSFC/RGC (N_CUHK406/12)NSFC (31270226 and 31470294)Shenzhen Peacock Project (KQTD201101) to L.Jiang
文摘Membrane trafficking is essential for plant growth and responses to external signals.The plant unique FYVE domain-containing protein FREE1 is a component of the ESCRT complex（endosomal sorting complex required for transport）.FREE1 plays multiple roles in regulating protein trafficking and organelle biogenesis including the formation of intraluminal vesicles of multivesicular body（MVB）,vacuolar protein transport and vacuole biogenesis,and autophagic degradation.FREE1 knockout plants show defective MVB formation,abnormal vacuolar transport,fragmented vacuoles,accumulated autophagosomes,and seedling lethality.To further uncover the underlying mechanisms of FREE1 function in plants,we performed a forward genetic screen for mutants that suppressed the seedling lethal phenotype of FREE1-RNAi transgenic plants.The obtained mutants are termed as suppressors of free1（sof）.To date,229 putative sof mutants have been identified.Barely detecting of FREE1 protein with M3 plants further identified 84 FREE1-related suppressors.Also145 mutants showing no reduction of FREE1 protein were termed as RNAi-related mutants.Through next-generation sequencing（NGS）of bulked DNA from F2 mapping population of two RNAi-related sof mutants,FREE1-RNAi T-DNA inserted on chromosome 1 was identified and the causal mutation of putative sof mutant is being identified similarly.These FREE1-and RNAi-related sof mutants will be useful tools and resources for illustrating the underlying mechanisms of FREE1 function in intracellular trafficking and organelle biogenesis,as well as for uncovering the new components involved in the regulation of silencing pathways in plants.
文摘A field under rice-wheat rotation was selected near Chengdu, China, to study thepopulation of Rhizoctonia solani anastomosis group 1 (AG-1), pathogen causing ricesheath blight disease, in natural soil ecosystem. Inocula of the fungus recovered fromthe field were divided into three types, i.e., sclerotia, free mycelium retained in thesoil passed through a 0.355mm sieve, and colonized plant debris which was subdividedinto small colonized debris retained between 2.00 and 0.355mm sieves and large colonizeddebris retained on 2.00mm sieve after wet screening. Quantitative estimation of thethree types of inocula in one year indicated that small colonized debris was the dominantinoculum type for most of the time. The population peaked in March and September at 1210and 480 colonized debris 100g-1 air-dry soil respectively, and fell down in December andAugust to 0 and 177 colonized debris 100g-1 air-dry soil respectively. Free mycelium wasonly detectable in March, September and October with 1209, 7.9 and 14.5g fresh wtmyceliumg-1 air-dry soil respectively, which corresponded to the two peaks and the secondhighest level of small debris density in the year. Viable sclerotia and large colonizeddebris were rare with populations ranging from 0 to 3 for sclerotia and 0 to 14 for largecolonized debris 100g-1 air-dry soil, but were the main structures to survive overwinter. It was expected that soil temperature was the main factor determining populationdynamics of R.solani AG-1 in natural soil. Optimum temperature for population increasingis predicted to be around 15℃, with a range from 10 to 25℃. Viability tests indicatedthat 60.9% sclerotia could survive after 265d being buried in natural sandy loam in fieldconditions in Beijing, while colonized rice straw debris (0.5-1.0cm long) could notyield the fungus on medium plates after 88d of being buried under the same conditions.
文摘Calcium homeostasis in synaptosomes is altered during aging. The intrasynaptomal free calcium concentration ([Ca2+]i) was determined in 3- and 24-month-old rats treated with or without Rbl and Rgl. As expected, the [Ca2-]i level increased with age. Treatment with Rbl and Rgl elicited an obvious decrease of [Ca2+]i content, especially in aged rates. In addition, Rbl and Rgl significantly stimulated the activity of Na+, K+-ATPase while Rbl inhibited the activity of Ca2+, Mg2--ATPase arid calmodulin. In view of the close relationship of [Ca2-]i level with aging, the changes of [Ca2+]i induced by Rbl and Rgl, as shown by our results, might provide an explanation of the mechanisms of their antiaging function.
