Chinese Academy Of Sciences Experts Successfully Cloned Key Genes For Cotton Fiber Elongation

GhHOX3 plays an important role in the process of fiber elongation, and the expression of GhHOX3 in cotton can make cotton fibers expand freely.

"This is one of the most valuable genes that have been found so far to control the length of cotton fiber," Chen Xiaoya said.

With the introduction of new concepts such as bamboo charcoal, pure cotton clothing still occupies a place in most people's wardrobe with its advantages of comfort, breathability and skin care.

Chinese demand for cotton fiber has not been reduced, but there is a huge gap in quality cotton production in China.

Recently, the research group of academician Chen Xiaoya, academician of Shanghai Institute of biological physiology, Chinese Academy of Sciences, has recently identified a key gene to control cotton fiber elongation, which will help alleviate this contradiction.

Let cotton fiber "freely extend" gene

According to statistics, more than 80 countries in the world grow cotton.

China is the largest producer and consumer of raw cotton. The number of people directly engaged in cotton textile and related industries has reached about 20000000, and the number of indirect employees has reached 100 million.

Cotton spinning industry plays a decisive role in China's national economy, and China's annual cotton self-sufficiency rate is only about 70%. The self-sufficiency rate of high-grade and high-quality cotton is lower, and it needs to import about one million tons of high quality raw cotton annually.

Cotton fiber is the most popular textile material, and the length of cotton fiber is an important index of cotton quality.

The researchers told reporters that cotton fibers are derived from the epidermal cells of cotton seeds and are the single cells with the longest elongation and the largest number of synthetic cellulose in higher plants.

The development process can be divided into 4 overlapping stages: differentiation and protuberance, rapid elongation, secondary wall synthesis and dehydration. Fiber elongation and secondary wall synthesis are closely related to quality traits.

"So far, there are relatively few studies on cotton fiber development, especially fiber elongation regulation."

Chen Xiaoya said with regret.

Through association analysis and genetic localization, they found a pcription factor GhHOX3 containing homeobox and related to cotton fiber elongation.

The "capture" gene named "GhHOX3" is hidden in many cotton genes and is a cotton elongation gene with important breeding value.

The study group found that GhHOX3 encoded a pcription factor, which promoted the elongation of cotton fiber cells by binding to the negative regulatory factor DELLA protein of gibberellin pathway and promoting the elongation of cotton fiber cells. It laid a foundation for further analyzing the molecular mechanism of plant cell elongation and cloning new genes of cotton fiber development, and also provided a target gene for cotton fiber quality improvement.

"Increasing the expression of GhHOX3 in cotton can increase the length of cotton fiber, while inhibiting the expression of the gene can significantly shorten the fiber length."

Chen Xiaoya then showed a close-up of cotton fiber to reporters. The two sides of the two sides were different cotton fibers grown in the laboratory after adjusting GhHOX3 expression.

It is clearly seen that the cotton fiber with low GhHOX3 expression is only about one centimeter long, while the cotton fiber with high GhHOX3 expression is several times longer than that of low expression cotton fiber.

It plays an important role in the process of fiber elongation. The expression of GhHOX3 in cotton can make cotton fibers "stretch freely".

Chen Xiaoya said: "this is one of the most valuable genes that have been found to control cotton fiber length."

After finding the key genes controlling the length of cotton fiber, the mechanism of gibberellin promoting the elongation of cotton fibers is also readily solved.

In the middle of the last century, the semi dwarf new varieties of wheat and rice have been widely applied in the whole world, which has solved the contradiction of "high yield lodging" of crops and made the total output of the world grain increase in a short time. Therefore, the severe crisis brought about by the rapid growth of population has been solved worldwide. It is the huge biological effect of phytohormone gibberellin that has brought the "green revolution" that benefits all mankind.

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The promotion of plant cell elongation, but the mechanism of gibberellin promoting cotton fiber elongation is not clear in the past.

Chen Xiaoya told reporters.

In order to reveal the regulatory mechanism of gibberellin in fiber development, the research group screened GhHOX3 as a "bait" in the experiment. It found that it could be combined with another pcription factor of the same class to form a heterologous two dimer related to cotton fiber elongation. The negative regulator of gibberellin pathway, DELLA protein, competed with the pcription factor, preempting the "preemption" of binding with GhHOX3, and hindered the formation of two dimers.

When gibberellin concentration increased, the DELLA protein was rapidly degraded, and the "bound" GhHOX3 was released to form a highly active two dimer, which activated the downstream gene expression and promoted the elongation of cotton fiber.

More hidden downstream genes "born"

GhHOX3 has been cloned and identified so that scientists can "lock" the target and pform GhHOX3 through experimental means, so that it can act as a cotton fiber to make cotton fibers longer.

"From the present experimental results, this elongation is not very obvious."

Chen Xiaoya said.

In addition to "making articles" on GhHOX3, scientists can use it to do "fish erbie" and "catch" to a series of downstream genes related to elongation of cotton fibers.

"In our previous studies, two cotton cell wall relaxin genes have been found to promote cotton fiber development.

In this experiment, we further demonstrate that GhHOX3 can directly integrate cis elements on the promoters of these two genes and activate their expression, and cell wall extension is a necessary condition for the elongation of cotton fibers.

Chen Xiaoya said.

These two cotton cell wall relaxation genes are two of the many downstream genes of GhHOX3.

Fiber elongation is a complex regulatory process. In order to further explore other downstream genes of GhHOX3, the research group screened 90 differentially expressed functional genes through high-throughput sequencing technology, and provided a number of important candidate genes for cotton fiber quality improvement.