How Did Cotton Evolve? Why Do Cotton Develop Fibers?

How did it evolve? Why did cotton develop fibers and synthesize gossypol?

Recently, the genome map of diploid cotton Raymond S cotton was completed by the Cotton Research Institute of Chinese Academy of Agricultural Sciences, Shenzhen Huada Gene Research Institute and Peking University.

The evolution of cotton genes, the initiation of fibers, the synthesis of important substances such as gossypol and so on have finally provided the basis for initial answers and explanations.

Why choose Raymond S cotton?

Why choose Raymond S cotton for research and genome mapping?

Researchers from the cotton genomics research team have told reporters that studies have shown that Raymond S cotton is one of the two donor species of the upland cotton ancestor, with 13 chromosomes.

At present, all kinds of cotton grown in the world are mainly tetraploid upland cotton and island cotton.

Among them, more than 95% of the cotton planted belongs to upland cotton.

Therefore, the complete genome map of Raymond cotton is very important for the sequencing of upland cotton genome. As the first cotton genome to be analyzed, it lays a good foundation for the study of the structural characteristics of the genome of upland cotton.

The cotton genomics research team used the whole genome shotgun method combined with the new generation of high-throughput DNA sequencing technology. Researchers used Raymond S cotton pure line as material to complete genome sequencing of Raymond's cotton, and obtained the complete genome sequence of 87.7%. By comparing genome and phylogenetic analysis, we found that Raymond's cotton and cocoa tree belong to the same branch, and the two probably differentiated about 33000000 years ago.

Liu Xu, vice president of the Chinese Academy of engineering and Chinese Academy of Agricultural Sciences, said the completion of the Raymond S cotton genome map marks the leading position in China's cotton genomics research.

It has provided an unprecedented opportunity for the excavation and utilization of important functional genes of cotton in China and even the whole genome design and breeding.

How did cotton evolve?

What is the evolution process of cotton development today?

By analyzing the collateral genes of Raymond S cotton and cocoa tree, researchers found that Raymond S cotton underwent a whole genome replication in 1300 to 20 million years ago.

This replica may not be the first gene duplication of Raymond cotton. Raymond's cotton may have undergone a genome duplication about 100 million years ago.

These findings are conducive to understanding the replication mechanism of ancient dicotyledonous plants.

After Raymond S cotton genome self comparison, researchers identified 2355 common regions, and found that about 40% of the homologous genes appeared in more than one common area, indicating that Raymond S cotton genome may have undergone a large number of dyed chromophore rearrangements during evolution.

Cotton is one of the most important cash crops in the world.

Its fibers, commonly known as lint, are

The main natural raw materials for industry.

The world's cotton planting area is about 500 million mu, and its annual planting area is nearly 80 million mu.

Cotton is also an excellent model system for studying polyploidy, cell elongation and cell wall biosynthesis.

Why do cotton develop such excellent fibers?

Cotton fiber is the most natural resource in the known fiber. Why does cotton grow such excellent fiber?

The results showed that the expression of sucrose synthase, 1- amino cyclopropane -1- carboxylate oxidase and 3- ketoyl -CoA synthetase in Raymond cotton was significantly lower than that in Upland Cotton on the 3 day after flowering, suggesting that these genes play an important role in the initiation and elongation of cotton fiber.

At the same time, because cotton fiber cells are single cells differentiated from ovule outer integument epidermal cells, their development can be divided into four overlapping and overlapping periods, including initiation, elongation, secondary wall deposition, dehydration and maturation. Because their development is highly consistent and homogeneous, and mature fibroblasts have extremely elongated morphology (the ratio of fiber cell length to its diameter can be 1000 to 3000 times), making cotton fiber cells become a good experimental system for studying the elongation and expansion of plant cells.

The study also found that there were 2706 pcription factors in the annotation of Raymond S cotton genome. A large number of MYB and bHLH pcription factors appeared in ovules of cotton on the 0 and 3 days after flowering, suggesting that these genes may be necessary for early fiber development.

Wired expert

Yu Shuxun, academician of Chinese Academy of engineering and director of Cotton Research Institute of Chinese Academy of Agricultural Sciences

Cotton breeding is expected to achieve molecular design at genomic level.

Since 2008, the whole genome sequencing of cotton has become a hot topic in the field of cotton basic research.

The next step is to develop rapid molecular breeding tools on the basis of the results, and to realize the breeding of cotton molecular design at the genome level, and cultivate new cotton varieties with high yield, high quality, disease resistance and drought resistance.

The combination of molecular assisted design and conventional breeding is an inevitable trend in future crop breeding research. Molecular assisted design breeding based on genomics research has greatly improved the accuracy of breeding selection, shortened breeding cycle and improved selection efficiency because of the large number of molecular markers, and not influenced by gene expression time, implicit relationship and environmental elements.

Starting from the most important food crops * rice genome project, a series of important agricultural species genome projects are being carried out and completed, including silkworm, domestic chicken, pig, soybean, corn, wheat, cotton, cabbage, potato, tomato and millet.

Under the background of dramatic changes in global climate, declining cultivated land resources and increasing greenhouse effect, vigorously cultivating and popularizing new crop varieties with high yield, good quality and environmental friendliness will help improve land use efficiency and increase crop yields.

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Extended reading

Researchers found that cottonseed, a key gene in gossypol synthesis, will become food resource.

Cotton is not only an important fiber and oil plant, but also an important source of plant protein.

In edible oil, linoleic acid content of cottonseed oil is the highest, reaching 55.6%.

In addition, cotton seeds also contain very rich protein and fat substances. Cottonseed oil has a high protein content of 45% - 50%, which is much better than that of rice and wheat, and even exceeds the protein content of peanut and soybean.

However, because the seeds and plants of common cotton cultivars have pigment glands, gossypol and its derivatives in pigment glands are toxic to human and mono gastric animals. Gossypol is a special compound of Gossypium, which directly restricts the development and utilization of cottonseed as food resources.

Thus, researchers compared with grapes, soybeans, cocoa, Arabidopsis papaya, castor, poplar, rice and other plants found that there is a special class of Du Songxi synthetase gene family in the cotton and cocoa genome, which is a key enzyme in gossypol synthesis pathway and a key step in the biosynthesis of gossypol.

This finding analyzes the origin and evolution of gossypol synthesis, enabling scientists to use genetic engineering technology to improve or reduce gossypol content in cottonseed. Therefore, cottonseed application in food resources is expected to become a reality.

Related news

Cotton is expected to cut production by 300 thousand tons this year.

The national development and Reform Commission revealed that the actual output of cotton in 2012 was about 6 million 900 thousand tons, a decrease of 300 thousand tons over the previous year and a decrease of 4.2%.

The national development and Reform Commission (NDRC) expects that China's cotton demand is more stable in 2012. Under the strong support of the temporary storage policy, the balance of the total supply and demand of cotton in China and the smooth operation of the market can be maintained through the effective use of international market resources and reserve regulation.

On the same day, Zhang Xiaoqiang, deputy director of the national development and Reform Commission, revealed that the actual output of cotton in 2012 was about 6 million 900 thousand tons, a decrease of 300 thousand tons over the previous year and a decrease of 4.2%.

The reasons for the reduction of cotton yield include "the decline of comparative income of seed cotton, the increase of production cost and other factors".

According to the website of the national development and Reform Commission, the import quota of grain and cotton imports in 2013 has been determined: 9 million 636 thousand tons of wheat, 90% of state trade, 7 million 200 thousand tons of corn, 60% of state trade, 5 million 320 thousand tons of rice, 50% of state Trade, 894 thousand tons of cotton and 33% of state-owned trade.

The quotas were unchanged from last year.

The first cotton spot trading platform in Central China will be trial run

China's first cotton spot trading platform, China (Tianmen) cotton trading center, will be put into trial operation by the end of this year.

By then, the cotton industry and cotton farmers in Hubei will benefit from the reduction of logistics and paction costs brought by this trading platform.

According to reports, China (Tianmen) cotton trading center, relying on the abundant cotton resources in Hubei, invested 6 billion yuan by Zhuo Er holdings, Tianmen and China Cotton store three party cooperation.

The trading center has 400 thousand square meters and the largest cotton storage center in the country. The annual storage capacity of cotton is 800 thousand tons, equivalent to 12% of the national annual output.

It is expected that

The center will be put into operation before the end of the year, and the scale of the paction will reach 20 billion yuan, which will strongly promote the development of cotton industry in Hubei province.