The“Green Revolution”spread worldwide due to the propagation of the causative gene of a semi-dwarf variety of wheat Norin 10 mutant,which was bred by Dr.Gonjiro Inazuka in 1935.This dwarf variety was later used to h...The“Green Revolution”spread worldwide due to the propagation of the causative gene of a semi-dwarf variety of wheat Norin 10 mutant,which was bred by Dr.Gonjiro Inazuka in 1935.This dwarf variety was later used to help produce high-yielding,semi-dwarf winter wheat varieties by Prof.Orille Vogel,which were then crossed with Mexican wheat varieties to produce a dwarf variety by Dr.Norman Borlaug in 1953.Dwarf wheat is more productive because it is less prone to lodging and allows higher nitrogen fertilizer application.The introduction of dwarf wheat to agriculture later contributed significantly to improve food security in developing countries by increasing world wheat productivity five-fold.The leader of the project,Dr.Borlaug,was awarded the Nobel Peace Prize for his work and is known as the father of the Green Revolution.Studies on wheat semi-dwarfism derived from Norin 10 by Prof.Mike Gale led to the molecular characterization of the Rht1 gene(Gale and Marshall,1976).In 1999,Prof.Harberd and his group identified the DELLA protein,a gibberellin(GA)signaling factor previously reported in Arabidopsis,as the causal gene corresponding to the phenotype Rht1 and demonstrated that variant forms of the GA–DELLA mechanism are crucial to yield(Peng et al.,1999).In rice,a GA biosynthesis mutant that exhibits a semi-dwarf phenotype due to stabilization of the rice DELLA protein SLR1 also played an important role in increasing yield(Sasaki et al.,2002).The induction of dwarfism through the use of GA biosynthesis inhibitors is also an important mechanism for increasing food production in wheat and rice(Rademacher,2000).However,this increase has recently reached a plateau.In addition,varieties used in the Green Revolution have low soil mineral nutrient(nitrogen)use efficiency(NUE)and rely on environmentally unsustainable fertilizer applications to achieve high yields.In this context,new approaches for increasing yields are essential for future food security by a way to coordinate high yield and NUE characteristics in cereal production.In 2018,Li et al.reported that the balanced opposing activities and physical interactions of the rice GROWTH-REGULATING FACTOR 4(GRF4)transcription factor and the growth inhibitor DELLA confer homeostatic co-regulation of growth and the metabolism of carbon and nitrogen(Li et al.,2018).The role of GRF4 is to enhance and combine the process of nitrogen assimilation,carbon fixation,and growth,while DELLA works in opposition to these functions.The accumulation of DELLA in Green Revolution varieties not only causes dwarfism and increases yield but also decreases the efficiency of nitrogen usage.Modulating the expression of GRF4 and rebalancing GRF4–DELLA toward GRF4 represent viable strategies to enhance nitrogen utilization efficiency and grain yield in Green Revolution cultivars.Therefore,GRF4 has the potential to contribute to further improving the productivity and sustainability of agriculture,which are key goals of the Green Revolution.However,a deeper understanding of the co-regulatory mechanisms of GRF4 that integrate growth,nitrogen assimilation,and carbon fixations is still necessary.展开更多
文摘The“Green Revolution”spread worldwide due to the propagation of the causative gene of a semi-dwarf variety of wheat Norin 10 mutant,which was bred by Dr.Gonjiro Inazuka in 1935.This dwarf variety was later used to help produce high-yielding,semi-dwarf winter wheat varieties by Prof.Orille Vogel,which were then crossed with Mexican wheat varieties to produce a dwarf variety by Dr.Norman Borlaug in 1953.Dwarf wheat is more productive because it is less prone to lodging and allows higher nitrogen fertilizer application.The introduction of dwarf wheat to agriculture later contributed significantly to improve food security in developing countries by increasing world wheat productivity five-fold.The leader of the project,Dr.Borlaug,was awarded the Nobel Peace Prize for his work and is known as the father of the Green Revolution.Studies on wheat semi-dwarfism derived from Norin 10 by Prof.Mike Gale led to the molecular characterization of the Rht1 gene(Gale and Marshall,1976).In 1999,Prof.Harberd and his group identified the DELLA protein,a gibberellin(GA)signaling factor previously reported in Arabidopsis,as the causal gene corresponding to the phenotype Rht1 and demonstrated that variant forms of the GA–DELLA mechanism are crucial to yield(Peng et al.,1999).In rice,a GA biosynthesis mutant that exhibits a semi-dwarf phenotype due to stabilization of the rice DELLA protein SLR1 also played an important role in increasing yield(Sasaki et al.,2002).The induction of dwarfism through the use of GA biosynthesis inhibitors is also an important mechanism for increasing food production in wheat and rice(Rademacher,2000).However,this increase has recently reached a plateau.In addition,varieties used in the Green Revolution have low soil mineral nutrient(nitrogen)use efficiency(NUE)and rely on environmentally unsustainable fertilizer applications to achieve high yields.In this context,new approaches for increasing yields are essential for future food security by a way to coordinate high yield and NUE characteristics in cereal production.In 2018,Li et al.reported that the balanced opposing activities and physical interactions of the rice GROWTH-REGULATING FACTOR 4(GRF4)transcription factor and the growth inhibitor DELLA confer homeostatic co-regulation of growth and the metabolism of carbon and nitrogen(Li et al.,2018).The role of GRF4 is to enhance and combine the process of nitrogen assimilation,carbon fixation,and growth,while DELLA works in opposition to these functions.The accumulation of DELLA in Green Revolution varieties not only causes dwarfism and increases yield but also decreases the efficiency of nitrogen usage.Modulating the expression of GRF4 and rebalancing GRF4–DELLA toward GRF4 represent viable strategies to enhance nitrogen utilization efficiency and grain yield in Green Revolution cultivars.Therefore,GRF4 has the potential to contribute to further improving the productivity and sustainability of agriculture,which are key goals of the Green Revolution.However,a deeper understanding of the co-regulatory mechanisms of GRF4 that integrate growth,nitrogen assimilation,and carbon fixations is still necessary.
