Background:Soil salinity seriously affects cotton growth,leading to the reduction of yield and fiber quality.Recently,genetic engineering has become an efficient tool to increase abiotic stress tolerance in crops.Resu...Background:Soil salinity seriously affects cotton growth,leading to the reduction of yield and fiber quality.Recently,genetic engineering has become an efficient tool to increase abiotic stress tolerance in crops.Results:In this study,isopentyl transferase(IPT),a key enzyme involved in cytokinin(CTK) biosynthesis from Agrobacterium tumefaciens,was selected to generate transgenic cotton via Agrobacterium-mediated transformation.A senescence-inducible SAG12 promoter from Arabidopsis was fused with the IPT gene.Ectopic-expression of SAG12::IPT significantly promoted seed germination or seedling tolerance to salt stress.Two IPTtransgenic lines,OE3 as a tolerant line during seed germination,and OE8 as a tolerant line at seedling stage,were selected for further physiological analysis.The data showed that ectopic-expression of SAG12::IPT induced the accumulation of CTKs not only in leaves and roots,but also in germinating seeds.Moreover,ectopic-expressing IPT increased the activity of antioxidant enzymes,which was associated with the less reactive oxygen species(ROS) accumulation compared with control plants.Also,ectopic-expression of IPT produced higher K^+/Na^+ratio in cotton shoot and root Conclusion:The senescence-induced CTK accumulation in cotton seeds and seedlings positively regulates salt stress partially by elevating ROS scavenging capability.展开更多
Cytokinins are members of a group of phytohormones involved in various growth and developmental processes in plants.Isopentenyl transferase(IPT)is the rate-limiting enzyme in catalyzing the biosynthesis of cytokinins....Cytokinins are members of a group of phytohormones involved in various growth and developmental processes in plants.Isopentenyl transferase(IPT)is the rate-limiting enzyme in catalyzing the biosynthesis of cytokinins.In this study,to understand the role of IPT family in cold resistance,78 IPT candidates were identified and characterized in nine Rosaceae genomes.The expansion of IPT families in the Rosaceae primarily occurred through segmental duplication rather than tandem duplication.In general,purifying selection controlled the evolution of IPT families in the Rosaceae,with IPT3 and IPT5 homologs as the primary drivers of evolution.Cis-elements,which are involved in the responses to many environmental stresses or phytohormone signals,were identified in the promoters of MdIPT members.This was consistent with the trends of expression of the MdIPT genes in apple(Malus domestica)calli.MdIPT5b was also found to exhibit multiple responses to phytohormones and stress signals.The ectopic expression of MdIPT5b resulted in an increase in cold resistance in transformed apple calli and tomato(Solanum lycopersicum)plantlets.The redox balance was partially stabilized through the accumulation of proline under cold stress.However,the ascorbate–glutathione cycle cannot be stabilized in the cold.All physiological and biochemical assays are preformed in spectrophotometer.These results showed that regulating the expression of IPT genes for moderate cytokinin improvement could enhance the accumulation of proline to stabilize the osmotic and redox balances to improve resistance to cold stress.展开更多
基金supported by The Genetically Modified Organisms Breeding Major Projects of China Grant(2016ZX08005-004)
文摘Background:Soil salinity seriously affects cotton growth,leading to the reduction of yield and fiber quality.Recently,genetic engineering has become an efficient tool to increase abiotic stress tolerance in crops.Results:In this study,isopentyl transferase(IPT),a key enzyme involved in cytokinin(CTK) biosynthesis from Agrobacterium tumefaciens,was selected to generate transgenic cotton via Agrobacterium-mediated transformation.A senescence-inducible SAG12 promoter from Arabidopsis was fused with the IPT gene.Ectopic-expression of SAG12::IPT significantly promoted seed germination or seedling tolerance to salt stress.Two IPTtransgenic lines,OE3 as a tolerant line during seed germination,and OE8 as a tolerant line at seedling stage,were selected for further physiological analysis.The data showed that ectopic-expression of SAG12::IPT induced the accumulation of CTKs not only in leaves and roots,but also in germinating seeds.Moreover,ectopic-expressing IPT increased the activity of antioxidant enzymes,which was associated with the less reactive oxygen species(ROS) accumulation compared with control plants.Also,ectopic-expression of IPT produced higher K^+/Na^+ratio in cotton shoot and root Conclusion:The senescence-induced CTK accumulation in cotton seeds and seedlings positively regulates salt stress partially by elevating ROS scavenging capability.
基金supported by the National Natural Science Foundation of China (Grant Nos. 32172522 and 31901974)the China Postdoctoral Science Foundation (Grant No. 2018M640205)+2 种基金the Earmarked Fund for China Agriculture Research System (Grant No. CARS-27)the 2115 Talent Development Program of China Agricultural Universitythe Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Nutrition and Physiology) in the Ministry of Agriculture and Rural Affairs, China
文摘Cytokinins are members of a group of phytohormones involved in various growth and developmental processes in plants.Isopentenyl transferase(IPT)is the rate-limiting enzyme in catalyzing the biosynthesis of cytokinins.In this study,to understand the role of IPT family in cold resistance,78 IPT candidates were identified and characterized in nine Rosaceae genomes.The expansion of IPT families in the Rosaceae primarily occurred through segmental duplication rather than tandem duplication.In general,purifying selection controlled the evolution of IPT families in the Rosaceae,with IPT3 and IPT5 homologs as the primary drivers of evolution.Cis-elements,which are involved in the responses to many environmental stresses or phytohormone signals,were identified in the promoters of MdIPT members.This was consistent with the trends of expression of the MdIPT genes in apple(Malus domestica)calli.MdIPT5b was also found to exhibit multiple responses to phytohormones and stress signals.The ectopic expression of MdIPT5b resulted in an increase in cold resistance in transformed apple calli and tomato(Solanum lycopersicum)plantlets.The redox balance was partially stabilized through the accumulation of proline under cold stress.However,the ascorbate–glutathione cycle cannot be stabilized in the cold.All physiological and biochemical assays are preformed in spectrophotometer.These results showed that regulating the expression of IPT genes for moderate cytokinin improvement could enhance the accumulation of proline to stabilize the osmotic and redox balances to improve resistance to cold stress.
