Fructokinase(FRK)is a regulator of fructose signaling in plants and gateway proteins that catalyze the initial step in fructose metabolism through phosphorylation.Our previous study demonstrated that MdFRK2 protein ex...Fructokinase(FRK)is a regulator of fructose signaling in plants and gateway proteins that catalyze the initial step in fructose metabolism through phosphorylation.Our previous study demonstrated that MdFRK2 protein exhibit not only high affinity for fructose,but also high enzymatic activity due to sorbitol.However,genome-wide identification of the MdFRK gene family and their evolutionary dynamics in apple are yet to be reported.A systematic genome-wide analysis in this study identified a total of nine MdFRK gene members,which could phylogenetically be clustered into seven groups.Chromosomal location and synteny analysis of MdFRKs revealed that their expansion in the apple genome is primarily driven by tandem and segmental duplication events.Divergent expression patterns of MdFRKs were observed in four source-sink tissues and at five different apple fruit developmental stages,which suggested their potential crucial roles in the apple fruit development and sugar accumulation.Reverse transcription-quantitative PCR(RT-qPCR)identified candidate NaCl or drought stress responsive MdFRKs,and transgenic apple plants overexpressing MdFRK2 exhibited considerably enhanced salinity tolerance.Our results will be useful for understanding the functions of MdFRKs in the regulation of apple fruit development and salt stress response.展开更多
This study described that a low-producing mutagenic strain was transformed to a l-lysine high-producing recombinant strain by optimizing the l-lysine metabolic pathway of Corynebacterium glutamicum.The nucleotide sequ...This study described that a low-producing mutagenic strain was transformed to a l-lysine high-producing recombinant strain by optimizing the l-lysine metabolic pathway of Corynebacterium glutamicum.The nucleotide sequence results revealed that the lysC of mutant strain CgK37 mutated at 279th codon.Based on this site,site-directed saturation mutation was performed to screen for the mutant with better effect in relieving aspartate kinase feedback inhibition.Then,the supply of oxaloacetate and nicotinamide adenine dinucleotide phosphate was increased via knockout and overexpression of related genes.In order to solve the problem of low utilization efficiency of culture medium,fructokinase gene gmuE was heterologous expressed in CgK37,which could directly use intracellular fructose to improve the growth rate.In addition,the synthesis of partial by-products was weakened at the gene transcription level to avoid carbon excessively flowing into the branch metabolism.Finally,a large-scale fermentation experiment was conducted in 5 L jar fermenter.The l-lysine yield of CgK37-11 was 196.58±1.68 g/L,which was 83.24%original higher than CgK37,and the productivity reached 2.46 g/L/h.展开更多
The formation of mature and fertile pollen grains, taking place inside the anther, depends on supply of assimilates, in the form of sucrose, provided mainly by the leaves. Data is limited, however, with respect to the...The formation of mature and fertile pollen grains, taking place inside the anther, depends on supply of assimilates, in the form of sucrose, provided mainly by the leaves. Data is limited, however, with respect to the understanding of sucrose metabolism in microspores and the supporting tissues. The aims of the present work were to 1) follow the changes in total and relative concentrations of sucrose, glucose, fructose and starch in the stamen parts and microspores up until anthesis, 2) follow the activities of sucrose-metabolism-related enzymes, in the anther walls fraction and microspores of the crop plant tomato. Sucrose was found to be partially cleaved in the filament, decreasing by more than twofold in the anther wall layers and the locular fluid, and to accumulate in the mature pollen grains, constituting 80% of total soluble sugars. Thus, sucrose was both the starting sugar, supporting microspore development, and the main carbohydrate accumulated at the end of the pollen-development program. The major invertase found to be active in both the anther wall layers and in maturing microspores was cell-wall-bound invertase. High fructokinase 2 and sucrose phosphate synthase activities during pollen maturation coincided with sucrose accumulation. The potential importance of sucrose accumulation during pollen dehydration phase and germination is discussed.展开更多
基金supported by the Yunnan Provincial Science and Technology Department Agriculture Joint Project,China(202301BD070001-020)。
文摘Fructokinase(FRK)is a regulator of fructose signaling in plants and gateway proteins that catalyze the initial step in fructose metabolism through phosphorylation.Our previous study demonstrated that MdFRK2 protein exhibit not only high affinity for fructose,but also high enzymatic activity due to sorbitol.However,genome-wide identification of the MdFRK gene family and their evolutionary dynamics in apple are yet to be reported.A systematic genome-wide analysis in this study identified a total of nine MdFRK gene members,which could phylogenetically be clustered into seven groups.Chromosomal location and synteny analysis of MdFRKs revealed that their expansion in the apple genome is primarily driven by tandem and segmental duplication events.Divergent expression patterns of MdFRKs were observed in four source-sink tissues and at five different apple fruit developmental stages,which suggested their potential crucial roles in the apple fruit development and sugar accumulation.Reverse transcription-quantitative PCR(RT-qPCR)identified candidate NaCl or drought stress responsive MdFRKs,and transgenic apple plants overexpressing MdFRK2 exhibited considerably enhanced salinity tolerance.Our results will be useful for understanding the functions of MdFRKs in the regulation of apple fruit development and salt stress response.
基金funded by the“Important Amino Acid Industrial Strain System Transformation and Industrial Demonstration”project[Grant Numbers 2021YFC2100900].
文摘This study described that a low-producing mutagenic strain was transformed to a l-lysine high-producing recombinant strain by optimizing the l-lysine metabolic pathway of Corynebacterium glutamicum.The nucleotide sequence results revealed that the lysC of mutant strain CgK37 mutated at 279th codon.Based on this site,site-directed saturation mutation was performed to screen for the mutant with better effect in relieving aspartate kinase feedback inhibition.Then,the supply of oxaloacetate and nicotinamide adenine dinucleotide phosphate was increased via knockout and overexpression of related genes.In order to solve the problem of low utilization efficiency of culture medium,fructokinase gene gmuE was heterologous expressed in CgK37,which could directly use intracellular fructose to improve the growth rate.In addition,the synthesis of partial by-products was weakened at the gene transcription level to avoid carbon excessively flowing into the branch metabolism.Finally,a large-scale fermentation experiment was conducted in 5 L jar fermenter.The l-lysine yield of CgK37-11 was 196.58±1.68 g/L,which was 83.24%original higher than CgK37,and the productivity reached 2.46 g/L/h.
文摘The formation of mature and fertile pollen grains, taking place inside the anther, depends on supply of assimilates, in the form of sucrose, provided mainly by the leaves. Data is limited, however, with respect to the understanding of sucrose metabolism in microspores and the supporting tissues. The aims of the present work were to 1) follow the changes in total and relative concentrations of sucrose, glucose, fructose and starch in the stamen parts and microspores up until anthesis, 2) follow the activities of sucrose-metabolism-related enzymes, in the anther walls fraction and microspores of the crop plant tomato. Sucrose was found to be partially cleaved in the filament, decreasing by more than twofold in the anther wall layers and the locular fluid, and to accumulate in the mature pollen grains, constituting 80% of total soluble sugars. Thus, sucrose was both the starting sugar, supporting microspore development, and the main carbohydrate accumulated at the end of the pollen-development program. The major invertase found to be active in both the anther wall layers and in maturing microspores was cell-wall-bound invertase. High fructokinase 2 and sucrose phosphate synthase activities during pollen maturation coincided with sucrose accumulation. The potential importance of sucrose accumulation during pollen dehydration phase and germination is discussed.
