Novel Molecular Plant Growth Regulator: Coronatine (COR)

Coronatine (COR) is a new plant growth regulator that is a structural analogue of Jasmonic Acid (JA), as well as the first industrial Jasmonic Acid molecular signal regulator in the world. Coronatine signaling molecules are involved in many physiological processes of plant growth and development. It has broad application potential during low temperature seed germination, improving crop stress resistance and disease resistance, as well as increasing yield, promoting coloring, and increasing sugar content, defoliation and biological weeding.

Discovery of Coronatine (COR)

1) In 1971, Ichihara discovered the fact that weeds often turn yellow and wither.

2) In 1976, Ichihara found that the yellowing and wilting of weeds were caused by a type of microorganism and extracted a substance from this microorganism, named, "Coronatine," which is the main substance that causes the yellowing of weeds.

3) In September 1976, Ichihara and others determined the structural formula of Coronatine through UV, IR and NMR.

Development of Coronatine in China

Chengdu Newsun Crop Science Co., Ltd. fully cooperated with the Engineering Research Center of Plant Growth Regulator at China Agricultural University to jointly develop Coronatine. Supported by the National "863 Plan" (National High-Tech Research and Development Plan) and a key R&D plan, a high-yield genetically-engineered strain of Coronatine was developed through transposon induced mutation and gene recombination. The production capacity of Coronatine reported both at home and abroad has increased by more than 5 to 10 times, and the world's first Coronatine fermentation production line was established at Chengdu Newsun. A large-scale membrane filtration concentration and refining process was also developed, producing Coronatine concentrate that can be used for preparation. Through the re-concentration process, over 98% pure Coronatine can be further prepared.

In December 2020, the registration application of 98% Coronatine Technical and 0.006% Coronatine AS submitted by Chengdu Newsun was approved and accepted by the Ministry of Agriculture and Rural Affairs, meaning that Coronatine will soon be registered.

Features of Coronatine

1. Stress resistance (cold resistance, drought resistance, salt-alkaline resistance, high temperature resistance), disease resistance, insect resistance and yield increase.

Jasmonates play an important role in a plant’s response to biotic and abiotic stresses, as well as in regulating the overall plant defense process.

Results showed that the signal molecules of Coronatine assist in the regulation of plant growth and development, especially as environmental signal molecules can effectively induce plant defense responses to pathogens, herbivores and abiotic stress, as well as encourage the expression of a series of defense genes and the synthesis of defensive chemicals, and regulate plant immune and stress reactions

2. Improves the quality of agricultural products (coloring and increasing sugar content)

Anthocyanidin is a type of anthocyanin, which, in turn, is a water-soluble natural pigment widely existing in plants. It is the main coloring substance in the leaves, pericarps and other organs of some plants. Coronatine can induce plant gene expression, activate anthocyanin and anthocyanin biosynthesis pathways, and improve the accumulation of high-level anthocyanins in the peel and pulp.

Coronatine can also improve the quality and yield of crops by increasing the photosynthetic rate and the accumulation of protein, amino acid and sugar in plants. It can be widely used to change color, increase sugar and flavor, and improve the quality of agricultural products.

Coronatine can improve the content and abundance of protein in plants

3. Defoliation and biological herbicide

Previous studies have shown that Coronatine can be used as a defoliant at high concentrations, especially for cotton and pepper, and has broad market application prospects for promoting agricultural mechanization harvests. At higher concentrations, Coronatine also has broad-spectrum herbicidal activity.

Application of Coronatine (COR) in crops

1. Soybean

The sensitivity of soybean to light and temperature, especially to low temperatures at the emergence stage, not only restricts the production of soybean in high latitude areas, but also affects the planting of southern spring soybeans, therefore, limiting the expansion of soybean planting areas and the improvement of yields in China. Soybean production is also closely related to food safety in the country. Current research shows that a certain concentration of Coronatine coating or seed dressing can improve the emergence rate of soybean under low temperature conditions, while spraying Coronatine at the seedling stage can improve yields, which can have a far-reaching impact on China's soybean agriculture and international soybean trade, and can be utilized as one of China's food safety strategic reserve technology to cope with the impact of global trade.

Using Coronatine for seed dressing increased soybean low temperature germination rate, while leaf spraying increased soybean yield.

2. Wheat, Rice

Wheat and rice are the China’s main grain crops, and their yield and quality are directly related to the country’s food security. Bad weather, such as dry hot air, causes more serious grain production reduction, from 10% to 20% in severe cases.

The results showed that under high temperature and drought stress, Coronatine was beneficial to maintaining high relative water content in wheat leaves, promoting the synthesis of soluble protein, improving the osmotic adjustment ability of cells, alleviating the damage of high temperature to plants to a certain extent, and enhancing their high temperature resistance. Thousand-seed weight and yield of wheat also increased.

3. Corn

According to the research results from the Crop Chemical Control Research Center of China Agricultural University, the soluble sugar and proline contents in the leaves of corn treated with Coronatine significantly increased. The stomatal opening degree of corn seedlings treated with Coronatine was also larger, increasing carbon dioxide input and making full use of the carbon dioxide absorbed by the stomata, to maintain higher photosynthesis, synthesize more dry matter, and increase the stem base and root length of corn seedlings.

 The results showed that Coronatine treatment significantly reduced plant height, increased the maximum diameter of internodes under the ear, and enhanced the anti-breaking ability of internodes, therefore, increasing the lodging resistance of corn stalks. Coronatine also significantly shortened internodes under the ear, reduced ear height, increased internode length above the ear, widened leaf spacing above the ear, reduced the lodging resistance of individual plant leaf area, shortened the transportation distance of nutrients and water to the ground, increased the cross-sectional area of transportation, achieved increased yields, and ensured a sufficient population, which created favorable conditions for reasonably close planting and lodging prevention. An appropriate concentration of Coronatine can also increase ear number, grain number per ear and 1,000-grain weight and reduce bald tip length.

4. Cotton

The results showed that Coronatine can increase cotton yields, enhance resistance to diseases, promote growth, strengthen stems, and ensure early maturity.

A low concentration of Coronatine can increase the salt tolerance of cotton, while high concentrations can promote the abscission of leaves, which is conducive to the mechanization of cotton harvest. Its effects and low cost will also offer broad market application value to cotton production.

5. Grape/Apple/ Citrus/Tomato

The results showed that the use of Coronatine during the germination/flower/young fruit stage can increase the accumulation of proline and other substances in new buds, significantly improving the resistance of fruits to low temperatures during the germination period and reducing losses caused by low temperatures. The use of Coronatine during the fruit coloring stage can improve the photosynthetic rate, increase the accumulation of protein, amino acids, sugar, pigments and other substances in plants, and, subsequently, improve the quality and yield of crops.

The grapes in the left photo were treated twice with Coronatine, while those on the right were treated twice with ethephon.

The grapes, which have fast coloring, high sugar content, good fruit powder and early marketing, were treated with Coronatine twice

Results: The tomatoes treated with Coronatine had better coloring, early marketing and good taste.

Technological innovation drives sustainable and green agriculture

Coronatine (COR) is a major agricultural science and technology innovation achievement with independent intellectual property rights in China. Through researching its physiological function, it has broad application potential for seed germination at low temperatures, as well as crop stress resistance, disease resistance, insect resistance and yield increase, promoting coloring and increasing sugar content, defoliation and biological weeding, with broad industrial and agricultural application prospects. Coronatine, as a biological fermentation product, also leaves no residue after use, is safer for the environment and agricultural products, and is widely used in organic and green agricultural production, which has far-reaching significance for ensuring agricultural green production and realizing the goal of China’s " Double Reduction of Chemical Pesticides and Chemical Fertilizers." The development of Coronatine products is a new chapter in the study of plant physiological regulation.

References

Chinese Journal of Pesticide Science, 2019, 21(1): 43-51

Plant Doctor, 2017, (5): 54-56

Journal of Anhui Agricultural Sciences, 2014, 42(9): 2537-2540

Agricultural Science & Technology (English edition), 2012 (3)