GDP-D-mannose pyrophosphorylase （GMPase） catalyses the synthesis of GDP-D-mannose and represents the first committed step in the synthesis of ascorbate. In the present study, the GMPase gene of tomato was introduced...GDP-D-mannose pyrophosphorylase （GMPase） catalyses the synthesis of GDP-D-mannose and represents the first committed step in the synthesis of ascorbate. In the present study, the GMPase gene of tomato was introduced into potato by Agrobacterium-mediated transformation. Two transgenic lines with higher GMPase expression were selected using qPCR and protein blot analyses. The results showed that the content of L-ascorbic acid （AsA） and the ratio of AsA/ DHA （dehydroascorbate） significantly increased in both leaves and tubers of transgenic potato plants. Both pigment content and photosynthetic rate were much higher in transgenic plants than in wild-type plants. Transgenic plants showed a distinguishable change in phenotype from the wild-type plants. Furthermore, transgenic plants showed delayed senescence.展开更多
L-Ascorbic acid （AsA） plays an important role in plants and animals. In plants, GDP-D-mannose pyrophosphorylase （GMP） is essential in the AsA biosynthetic pathway. However, little is known about the genes encoding...L-Ascorbic acid （AsA） plays an important role in plants and animals. In plants, GDP-D-mannose pyrophosphorylase （GMP） is essential in the AsA biosynthetic pathway. However, little is known about the genes encoding GMP in soybean and here we report genetic and functional analysis of the GmGMP1 （Glycine max GDP-D-mannose pyrophosphorylase 1） gene in this species. GmGMP1 encoded a GDP-mannose pyrophosphorylase and exhibited higher transcript levels in the leaf than in the root, stem, flower, and seed. Transcript of this gene was ubiquitous in the vegetative and reproductive organs, and was induced by abiotic stress and light. Increasing expression of GmGMP1 in Arabidopsis and soybean through an overexpressing approach caused pronounced enhancement of AsA content, and was implicated in lowering the superoxide anion radical content and lipid peroxidation levels in Arabidopsis, and conferring tolerance to osmotic and high salt stresses during seed germination. The present study represents the first systematic determination of soybean genes encoding GDP-mannose pyrophosphorylase and provides useful evidence for the functional involvement of GmGMP1 in control of AsA content and conferring tolerance to osmotic and salt stress.展开更多
Ammonium （NH4^＋） is an important form of nitrogen nutrient for most plants, yet is also a stressor for many of them. However, the primary events of NH4^＋ toxicity at the cellular level are still unclear. Here, we ...Ammonium （NH4^＋） is an important form of nitrogen nutrient for most plants, yet is also a stressor for many of them. However, the primary events of NH4^＋ toxicity at the cellular level are still unclear. Here, we showed that NH4^＋ toxicity can induce the root cell death in a temporal pattern which primarily occurs in the cells of root maturation and elongation zones, and then spreads to the ceils in the meristem and root cap. The results from the NH4^＋-hypersensitive mutant hsn1 further confirmed our findings. Taken together,NH4^＋ toxicity inhibits primary root growth by inhibiting cell elongation and division and inducing root cell death.展开更多
基金supported by the National Basic Re-search Program of China (2009CB119000)the National Natural Science Foundation of China (30771473)funded by Key Laboratory of Horticultural Crops Ge-netic Improvement, Ministry of Agriculture of China
文摘GDP-D-mannose pyrophosphorylase （GMPase） catalyses the synthesis of GDP-D-mannose and represents the first committed step in the synthesis of ascorbate. In the present study, the GMPase gene of tomato was introduced into potato by Agrobacterium-mediated transformation. Two transgenic lines with higher GMPase expression were selected using qPCR and protein blot analyses. The results showed that the content of L-ascorbic acid （AsA） and the ratio of AsA/ DHA （dehydroascorbate） significantly increased in both leaves and tubers of transgenic potato plants. Both pigment content and photosynthetic rate were much higher in transgenic plants than in wild-type plants. Transgenic plants showed a distinguishable change in phenotype from the wild-type plants. Furthermore, transgenic plants showed delayed senescence.
基金supported by the Genetically Modified Organisms Breeding Major Projects, China (2016ZX08004)the earmarked fund for China Agriculture Research System (CARS-004-PS10)the Program for Changjiang Scholars and Innovative Research Team in University, China (PCSIRT13073)
文摘L-Ascorbic acid （AsA） plays an important role in plants and animals. In plants, GDP-D-mannose pyrophosphorylase （GMP） is essential in the AsA biosynthetic pathway. However, little is known about the genes encoding GMP in soybean and here we report genetic and functional analysis of the GmGMP1 （Glycine max GDP-D-mannose pyrophosphorylase 1） gene in this species. GmGMP1 encoded a GDP-mannose pyrophosphorylase and exhibited higher transcript levels in the leaf than in the root, stem, flower, and seed. Transcript of this gene was ubiquitous in the vegetative and reproductive organs, and was induced by abiotic stress and light. Increasing expression of GmGMP1 in Arabidopsis and soybean through an overexpressing approach caused pronounced enhancement of AsA content, and was implicated in lowering the superoxide anion radical content and lipid peroxidation levels in Arabidopsis, and conferring tolerance to osmotic and high salt stresses during seed germination. The present study represents the first systematic determination of soybean genes encoding GDP-mannose pyrophosphorylase and provides useful evidence for the functional involvement of GmGMP1 in control of AsA content and conferring tolerance to osmotic and salt stress.
基金Project supported by the National Basic Research Program (973) of China (No.2005CB120901)the China Postdoctoral Science Foundation (No.20090451463),the China Postdoctoral Special Foundation (No.201003729)
文摘Ammonium （NH4^＋） is an important form of nitrogen nutrient for most plants, yet is also a stressor for many of them. However, the primary events of NH4^＋ toxicity at the cellular level are still unclear. Here, we showed that NH4^＋ toxicity can induce the root cell death in a temporal pattern which primarily occurs in the cells of root maturation and elongation zones, and then spreads to the ceils in the meristem and root cap. The results from the NH4^＋-hypersensitive mutant hsn1 further confirmed our findings. Taken together,NH4^＋ toxicity inhibits primary root growth by inhibiting cell elongation and division and inducing root cell death.
