Thousands of plants can produce fruits, seeds and other edible parts, but only a few hundred plants are cultivated by humans worldwide, and human survival and reproduction depend only on dozens of them. These major food crops have undergone drastic phenotypic changes in the process of human domestication, making them more and more in line with human production needs, which we call the "agricultural revolution". The agricultural revolution brought about an increase in food production and allowed crops to be grown on a large scale. In the face of the increasing population problem, if the agricultural revolution can be accelerated and those unexploited plants can be put on people's tables, it will undoubtedly bring more food sources to mankind.
On September 5, 2019, Science magazine published online a review article entitled "Revolutions in agriculture chart a course for targeted breeding of old and new crops" co-authored by Professor Yuval Eshed of the Weizmann Institute of Science (Weizmann Institute of Science) and Professor Zachary B.Lippman of Cold Spring Harbor Laboratory in the United States. They proposed to edit the two hormone systems of "flowering hormone" and "gibberellin" and apply them to new and old crops, which will meet the future dietary needs of human beings and promote the sustainable development of agriculture. The agricultural revolution was driven by two hormone systems, the "flower hormone" (Florigen) that controls flowering and the "gibberellin" (Gibberellin) that controls plant type. The modification of these two hormone systems has improved the shape of the plant, including more rapid maturity, concentrated flowering and fruit setting, and shorter plant height (lodging resistance).

Plants begin to flower when the level of "anorexin" is high enough to stimulate terminal buds to flower, and the newly formed vegetative buds are temporarily inhibited by locally produced "antianorexin" signals. The first discovered "antiflorin" signal came from a study of the tomato self pruning(sp) mutant, a rare natural variation found in U.S. farmland in the 1820 s. In a vegetable field full of tomatoes, this mutant plant is tall and short, with few branches, as if it had been pruned. It enabled large-scale tomato cultivation and transformed the agricultural landscape of California's Central Valley (Figure 2A). In short, the mutation of sp gene destroys the signal of "anti-flowering element" and relieves the inhibition of "anti-flowering element" on the activity of "flowering element" in lateral buds, which changes tomato from infinite cycle of vegetative growth and reproductive growth to continuous concentrated flowering, and produces tomato varieties that bloom and produce fruits on a large scale at the same time, which makes tomato applied in agricultural production. Similar benefits were brought in the mutant of the homologous gene in soybean (determinate stem,dt1) and the sp mutant of cotton (Figure 2B; Figure 2C).
The "gibberellin" hormone system regulates plant height. After synthesis through a multi-step complex pathway, active gibberellins are sensed by the intracellular receptor Gibberellin Insensitive Dwarf 1(GID1), which in turn directs the degradation of a growth inhibitory protein, DELLA. The introduction of a gain-of-function DELLA mutation in wheat more than 50 years ago and a mutation in a gibberellin biosynthetic gene in rice both produced a shorter plant height phenotype. Breeders use these "dwarf genes" to reduce plant height and avoid lodging and yield losses caused by the use of chemical fertilizers to allow plants to grow unrestrained. Wheat is a hexaploid plant, and mutations in the homologous gene of the Reduced height-1(Rht-1) gene encoding the DELLA protein inhibit gibberellin signaling to varying degrees. Among them, semi-dwarf Rht-B1b and Rht-D1b mutations are found in most of the current wheat lines (Figure 3). The discovery of these mutants led to a doubling of wheat and rice yields during the Green Revolution in the 1870 s, providing food for hundreds of millions of people.
Using CRISPR-Cas genome editing systems, breeders can more quickly and directionally change genes to obtain desired mutants. At the same time, genome editing has accelerated the domestication of crops that have not been widely exploited. For example, Lippman research group has improved the distant relative of tomato, "girl fruit", in terms of branch structure, flowering and fruit size through gene editing technology.
The authors propose that the directed generation of genetic variation in the core components of the two major hormone systems, "florin" and "gibberellin", will cause more extensive phenotypic variation. The introduction of this breeding model into traditional and underutilized crops can meet future human dietary needs and sustainable agricultural development.