The somatic hybrid KT1 was previously obtained from protoplast fusion between sweetpotato （Ipomoea batatas （L.） Lam.） cv. Kokei No. 14 and its wild relative I. triloba L. However, its genetic and epigenetic variat...The somatic hybrid KT1 was previously obtained from protoplast fusion between sweetpotato （Ipomoea batatas （L.） Lam.） cv. Kokei No. 14 and its wild relative I. triloba L. However, its genetic and epigenetic variations have not been investigated. This study showed that KT1 exhibited significantly higher drought tolerance compared to the cultivated parent Kokei No. 14. The content of proline and activities of superoxide dismutase （SOD） and photosynthesis were significantly increased, while malonaldehyde （MDA） content was significantly decreased compared to Kokei No. 14 under drought stress. KT1 also showed higher expression level of well-known drought stress-responsive genes compared to Kokei No. 14 under drought stress. Amplified fragment length polymorphism （AFLP） and methylation-sensitive amplified polymorphism （MSAP） analyses indicated that KT1 had AFLP and MSAP band patterns consisting of both parent specific bands and changed bands. Fur- ther analysis demonstrated that in KT1. the proportions of Kokei No. 14 specific genome components and methylation sites were much greater than those of I. triloba. KT1 had the same chloroplast and mitochondrial genomes as Kokei No. 14. These results will aid in developing the useful genes ofI. triloba and understanding the evolution and phylogeny of the cultivated sweetpotato.展开更多
As metabolic centers, plant organelles participate in maintenance, defense, and signaling. MSH1 is a plant- specific protein involved in organeUar genome stability in mitochondria and plastids. Plastid depletion of MS...As metabolic centers, plant organelles participate in maintenance, defense, and signaling. MSH1 is a plant- specific protein involved in organeUar genome stability in mitochondria and plastids. Plastid depletion of MSH1 causes heritable, non-genetic changes in development and DNA methylation. We investigated the rash I phenotype using hemi-complementation mutants and transgene-null segregants from RNAi suppres- sion lines to sub-compartmentalize MSH1 effects. We show that MSH1 expression is spatially regulated, specifically localizing to plastids within the epidermis and vascular parenchyma. The protein binds DNA and localizes to plastid and mitochondrial nucleoids, but fractionation and protein-protein interactions data indicate that MSH1 also associates with the thylakoid membrane. Plastid MSH1 depletion results in variegation, abiotic stress tolerance, variable growth rate, and delayed maturity. Depletion from mitochon- dria results in 7%-10% of plants altered in leaf morphology, heat tolerance, and mitochondrlal genome sta- bility. MSH1 does not localize within the nucleus directly, but plastid depletion produces non-genetic changes in flowering time, maturation, and growth rate that are heritable independent of MSH 1. MSH1 deple- tion alters non-photoactive redox behavior in plastids and a sub-set of mitochondrially altered lines. Ectopic expression produces deleterious effects, underlining its strict expression control. Unraveling the complexity of the MSH1 effect offers insight into triggers of plant-specific, transgenerational adaptation behaviors.展开更多
Small RNAs are found in eukaryotes and are responsible for regulation of chromatin structure, RNA processing and stability, translation and transcription. 24-nt small interfering RNA (siRNA) are known to mediate gene ...Small RNAs are found in eukaryotes and are responsible for regulation of chromatin structure, RNA processing and stability, translation and transcription. 24-nt small interfering RNA (siRNA) are known to mediate gene inactivation via the RNA-directed DNA methylation pathway (RdDM) and are important for natural heritable changes in plant species. DNA cytosine methylation can be maintained between generations and this may be important for accelerated adaption to stress conditions. Research is currently focused toward the epigenetic response to disease, the stability of DNA methylation over generations, the elucidation of newly discovered pathways for de novo DNA methylation, and the application of epigenetic variation to breeding programs. This review aims to give a brief but comprehensive examination on small RNAs and transgenerational epigenetic variation.展开更多
基金supported by the China Agriculture Research System(CARS-11,Sweetpotato)the National Natural Science Foundation of China(31461143017)
文摘The somatic hybrid KT1 was previously obtained from protoplast fusion between sweetpotato （Ipomoea batatas （L.） Lam.） cv. Kokei No. 14 and its wild relative I. triloba L. However, its genetic and epigenetic variations have not been investigated. This study showed that KT1 exhibited significantly higher drought tolerance compared to the cultivated parent Kokei No. 14. The content of proline and activities of superoxide dismutase （SOD） and photosynthesis were significantly increased, while malonaldehyde （MDA） content was significantly decreased compared to Kokei No. 14 under drought stress. KT1 also showed higher expression level of well-known drought stress-responsive genes compared to Kokei No. 14 under drought stress. Amplified fragment length polymorphism （AFLP） and methylation-sensitive amplified polymorphism （MSAP） analyses indicated that KT1 had AFLP and MSAP band patterns consisting of both parent specific bands and changed bands. Fur- ther analysis demonstrated that in KT1. the proportions of Kokei No. 14 specific genome components and methylation sites were much greater than those of I. triloba. KT1 had the same chloroplast and mitochondrial genomes as Kokei No. 14. These results will aid in developing the useful genes ofI. triloba and understanding the evolution and phylogeny of the cultivated sweetpotato.
文摘As metabolic centers, plant organelles participate in maintenance, defense, and signaling. MSH1 is a plant- specific protein involved in organeUar genome stability in mitochondria and plastids. Plastid depletion of MSH1 causes heritable, non-genetic changes in development and DNA methylation. We investigated the rash I phenotype using hemi-complementation mutants and transgene-null segregants from RNAi suppres- sion lines to sub-compartmentalize MSH1 effects. We show that MSH1 expression is spatially regulated, specifically localizing to plastids within the epidermis and vascular parenchyma. The protein binds DNA and localizes to plastid and mitochondrial nucleoids, but fractionation and protein-protein interactions data indicate that MSH1 also associates with the thylakoid membrane. Plastid MSH1 depletion results in variegation, abiotic stress tolerance, variable growth rate, and delayed maturity. Depletion from mitochon- dria results in 7%-10% of plants altered in leaf morphology, heat tolerance, and mitochondrlal genome sta- bility. MSH1 does not localize within the nucleus directly, but plastid depletion produces non-genetic changes in flowering time, maturation, and growth rate that are heritable independent of MSH 1. MSH1 deple- tion alters non-photoactive redox behavior in plastids and a sub-set of mitochondrially altered lines. Ectopic expression produces deleterious effects, underlining its strict expression control. Unraveling the complexity of the MSH1 effect offers insight into triggers of plant-specific, transgenerational adaptation behaviors.
文摘Small RNAs are found in eukaryotes and are responsible for regulation of chromatin structure, RNA processing and stability, translation and transcription. 24-nt small interfering RNA (siRNA) are known to mediate gene inactivation via the RNA-directed DNA methylation pathway (RdDM) and are important for natural heritable changes in plant species. DNA cytosine methylation can be maintained between generations and this may be important for accelerated adaption to stress conditions. Research is currently focused toward the epigenetic response to disease, the stability of DNA methylation over generations, the elucidation of newly discovered pathways for de novo DNA methylation, and the application of epigenetic variation to breeding programs. This review aims to give a brief but comprehensive examination on small RNAs and transgenerational epigenetic variation.
