The microcosm behind soybean flowering and high yields

“ Compared with the main soybean producing countries, China's soybean yield is low, the key technology still needs to be broken. Increasing yield is the most important problem facing our soybean researchers at present. Kong Fanjiang, a researcher at Guangzhou University's Center for Molecular Genetics and Evolutionary Innovation, told China Science Daily.
lucky that the research team's long-term persistence and systematic in-depth research have made new breakthroughs in recent years.
Recently, Kong Fanjiang, in collaboration with his colleague Liu Baohui, and Tian Zhixi, a researcher at the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences, systematically reported for the first time on the evolution and selection of molecular mechanisms of the flowering gene during soybean domestication, and confirmed that light cycle flowering is the domestication characteristic of the core of the crop. This has laid a theoretical foundation for soybean molecular module mining and design breeding, and cultivating high-yield, high-quality soybean cultivar varieties. The findings were published in nature-genetics.about 5000 years ago, cultivated soybeans originated in China, and wild soybeans in the Huanghuaihai region at latitudes 30 to 45 degrees north were domesticated for today's cultivated soybeans. Soybean-processed food plays an important role in China's food culture, and soy products such as tofu and soy sauce are one of the important heritages of Chinese civilization.
past studies show that soybeans are sensitive to light cycles of high temperature short-light crops, maturation is one of the important factors affecting soybean yield and quality. In most plant growth and development process, must go through a certain period of time after the length of the sun before flowering, otherwise it will always be in a nutritional growth state. The phenomenon of light cycle, that is, the alternating effect of light period and dark period in day and night cycle, affects the flowering effect of plants.
" soybeans' response to light cycles usually affects the length of maturity and thus yield. This is reflected in the short lighting time, early flowering period, early maturation and low yield of the same species in low latitudes, while in high latitudes the lighting time is long, late flowering, late maturation and high yield. Kong Fanjiang, one of the authors of the paper' newsletter, said.
, however, the range of soybean cultivation has expanded considerably, both in russia at high latitudes and in countries such as Brazil near the equator.
soybeans reduce their sensitivity to light cycles and make themselves a wide range of ecological adaptability? Is this a naturally chosen variation or the result of artificial domestication?
, one of the authors of the paper, has been studying soybean importance genetics and functional genes for 20 years. He told China Science that the process of domestication of crops from wild to farm species has undergone a series of artificial improvements, such as reduced sleep, seed granulation, etc., which have also become "comprehensive characteristics of domestication". There has always been a debate about whether the light cycle is a comprehensive characteristic of domestication.
researchers used a combination of genomics analysis, bio-information and classical positive genetics to identify and clone two key bits, Tof11 and Tof12, that regulate the soy light cycle.
study found that the selection of bluntness in the light cycle of the Tof12-1 gene may be a key event in early domestication of soybeans, possibly accompanied by the selection of drop,1,000, seed hardness, and sleepability in the Shat1-5, GmHs1-1, and G genes. This result confirms that light cycle adaptive changes may be an important evolutionary step in early crop domestication and are the domestication of soybean crop cores.the current widespread soybean cultivation, due to its high sensitivity of the light cycle characteristics, a single soybean variety can adapt to a narrow latitude range. This is not conducive to the promotion of soybean varieties.
, for example, we hope that the varieties of the north will also be highly produced in the south. Kong Fanjiang said. However, the reality is that Harbin varieties get Guangzhou will flower early, plants small, only grow a few centions, very few particles;
, what genes regulate soybean light cycles and flowering? What is the regulatory mechanism? How to solve the contradiction between high soybean yield and precocious? This is a problem that researchers have been trying to solve.
past studies of model plant athropophymes have found that, as the core component of the biological clock, the PRRs family gene performs complex and orderly rhythmic expressions through the regulation of downstream genes to complete the flowering of light cycles. "In crops such as rice and wheat, we have also discovered the PRRs gene, which is the same source as athropomorth, and plays an important role in regulating the light cycle pathway. We want to know how the gene functions in soybeans. Liu Baohui said.
are genes inherited from different species by a common ancestor, and they may function in the same way or may produce functional differentiation.
, studies have shown that Tof11 and Tof12 are a pair of 1st-origin genes that encode the PRR class. Through the analysis of molecular mechanism, the results show that Tof11 and Tof12 inhibit the core E1 of the light cycle regulation of legumes by weakening the biological clock gene LHY, resulting in a decrease in the expression of the anthotin gene FT, which ultimately delays flowering. Based on this, the author establishes and reveals a complete network of light cycle regulatory molecules in soybeans.
evolutionary mechanisms, the study also found that Tof11 and Tof12 undergone progressive mutations and artificial selection. Among them, tof12-1 functional deficiency mutation is strongly selected and quickly fixed in the cultivar, so that the flowering and maturation of the cultivated varieties are generally ahead of time.
In addition, tof11-1 functional deficiency mutation occurs after tof12-1 and is selected again on the tof12-1 genetic background, thus further shortening the flowering and reproductive period of cultivated soybeans and improving the adaptability of cultivated soybeans.
50% of the genetic diversity of wild soybeans lost in cultivated soybeans during domestication. Therefore, by excavating and clearly controlling the key genes and their molecular mechanisms of important agronomic characters, we can try to 'pick up' the genes lost in wild soybean domestication to control fine characters and use them in molecular design breeding to see if they can increase yields. Kong Fanjiang said.is an important grain and oil crops, but also the main source of high-quality human protein and animal husbandry feed protein, which plays an important role in China's grain structure. However, China's soybean yield is still low, the degree of external dependence as high as 85%, is the world's largest soybean importer.
the past few decades, food crops such as rice and wheat have undergone a "green revolution" in yields due to the mining of key genes and the advantages of hybrids. Soybeans, by contrast, have been growing slowly.
" soybean gene research is more difficult. Kong Fanjiang admits that one reason is that soybeans are due to the evolution of the ancient quaterus of the double self-handed crop, the genome is huge, about 56,000 genes, and 75% of the genes in the form of congenital genes, the low degree of genetic variation, rich repeat sequence makes the soybean genome very complex, genetic transformation difficulties, which is holding back the progress of soybean gene function research.
fact, soybean scientists have not given up for decades, groping ahead.
note that in 2017, Kong Fanjiang, Liu Baohui and Tian Zhixi and their team of collaborators cloned and verified the function of J, a key gene in soybean's long-term childhood. Long-term child sex can prolong the growth of soybean nutrition and increase soybean yield under short sun conditions, so that soybeans can be grown and popularized in large areas of tropical equatorial areas.
study found that the J gene promotes the flowering of the light cycle, and that the gene variant can delay soybean flowering time at low latitudes under short sun conditions, increasing yields by 30% to 50% compared to wild ones. In addition, the J gene has at least 8 functionally-deficit allethm variations in the adaptation of low-latitude soybean varieties, which plays an important role in the promotion and production of soybeans in low-latitude areas.
" two studies complement each other, is a continuous process, not only to further improve the E1-based key nodes of soybean flowering molecular regulation network, but also systematically explained the J gene to promote soybean low-latitude adaptation, and Tof11 and Tof12 to promote soybean mid- and high-latitude adaptation of multi-gene evolution mechanism. Kong Fanjiang said. Despite some breakthroughs and advances, this is only the "tip of the iceberg" in terms of the huge genome, and there are still many questions to be answered behind the evolution and selection of soybeans.
In addition to the light cycle, at present, China has made great progress in the key genes of yield importance such as 100 grain weight, single plant number, leaf handle angle, etc., and has also created a number of soybean excellent seed materials, which has laid an important theoretical foundation for soybean molecular design and breeding.
the molecular design breeding technology, which was jointly developed by the university, is a new change in modern breeding. "Speed up the construction of the molecular design breeding innovation system, carry out research on the molecular basis and breeding technology of soybean super-high yield, create revolutionary varieties and realize the 'green revolution' of soybeans, so as to reverse the passive situation of soybeans in China." Tian Zhixi, one of the authors of the paper's newsletter, said.
Tian Zhixi said that yield, quality and other characters are mostly complex features of multi-gene control, and the coupling between different complexity is a key scientific problem in molecular design breeding. We also need to analyze the genetic regulatory networks that are coupled between complex shapes and identify the key regulatory units. "Based on these studies, we can also screen out marginal lands suitable for saline, beach, high cold, high drought, and soybean materials and quality growing north of Heilongjiang's main production areas, expanding planting area and increasing yields."
" At present, the basic research level of soybeans compared with rice and corn and other major crops is still very weak, but also need the country's more attention and input, scientific research personnel work together, cohesion to dig more important genes and breakthrough key technologies, the old ancestors left to our heritage to protect and carry forward. Kong Fanjiang said.