AgroPages-Chengdu New Sun: Making breakthroughs in industrialized application of plant growth regulation coronatine, first time in the world-Agricultural news

Editor：Mickey Shan

Feature : Showcase of China’s ″Specialized and Novel″ crop protection products/technologies/applications

▋ Special sponsor: Lansheng Biotechy

▋ A total of 11 enterprises are introduced in this series; The Feature was first published in the latest "2023 China Pesticide Industry Watch"

The overall industrial upgrading of Chinese manufacture industry happens to coincides with the unprecedented changes in the last 100 years.

In this new era full of opportunities and policy support, the Chinese pesticide enterprises have worked hard to achieve constant technical breakthroughs via innovation and upgrading, as based on the experiences gained in the past decades. Some enterprises have so far made preliminary achievements, having formed an advanced and sophisticated technology and product cluster.

In this Feature, we have selected 11 Chinese pesticide manufacturers that are characterized with professionalism, intensification, specialization and novelty, which is a presentation of Chinese pesticide enterprise’s research and development of new products, breakthroughs in technical innovation, upgrading of type of formulations and continued exploration of applications. The publication will exhibit the achievements in each individual sector, which is internationally advanced, revealing the new competitiveness of Chinese pesticide industry.

▉Series of special topics are released in succession → specially planned by AgroPages

【 Chengdu New Sun: Making breakthroughs in industrialized application of plant growth regulation coronatine, first time in the world】

In recent years, extreme weather has occurred more and more frequently, causing intensive abiotic stresses on global agriculture.

The abiotic stresses such as drought, high temperature, chilling injury, and salt injury are restraining the regular growth of crops, which reduce seedling tolerance, plant disease resistance, vegetative growth and reproductive growth, resulting in loss of crop yield and decline in quality.

Plant growth regulators are usually used to induce a crop’s capability of stress resistance. However, most plant growth regulators have minimal functions and have a concentration requirement. Therefore, the discovery of the jasmonic acid signal molecule regulator coronatine is of significance to improve food security and the healthy and sustainable development of global agriculture.

Bacterial toxins are usually the secondary metabolites of microorganisms. These active substances can interfere with the regular physiological function of plant cells or can directly kill cells. Plant pathogens use a series of bacterial toxins to inhibit the host defense to achieve the purpose of infection of hosts. In 1977, Ichihara and others isolated a compound from the culture solution of Pseudomonas syingaepv. acropurpurpurea, a non-host-specific bacterial toxin that can cause verticillium wilt in various plants named coronatine. Through years of study, researchers found that coronatine has functions similar to abscisic acid and jasmonic acid, which are of physiological functions such as regulation of growth, inhibition of aging, promotion of cell differentiation, increase in chlorophyll content and plant adverse resistance.

Coronatine is an analogue of the plant hormone methyl jasmonate (MeJA) (Figure 1). As an environment-friendly biological plant growth regulator, coronatine needs only a very low concentration to function. Its biological activity is 100-10,000 times that of methyl jasmonate. Coronatine signal molecules can regulate many physiological and biochemical processes, such as plant growth and development and adversity stress via jasmonic acid approaches. Hence, coronatine has a broad application prospect in defoliation, excessive growth control, weeding, promotion of coloring, sugar degree enhancement, low-temperature seed germination, stress resistance, disease resistance and insect resistance.

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Figure 1 Structural comparison of coronatine and methyl jasmonate

First coronatine fermentation line established

Since the discovery of coronatine, it has been a hot subject of research in plant hormones as to how pure coronatine can be obtained. Due to its complex synthesis process, high cost and difficulty in industrialization, the application of coronatine is quite restricted.

After nearly 20 years of scientific research, Chengdu New Sun, along with the Plant Growth Regulator Engineering Research Center of China Agricultural University, has had a series of achievements in the industrial production of coronatine: Application of transposon induced mutation and genetic recombination to construct a high-yield genetic engineering strain of coronatine, which is five to ten times higher than the yield level was reported at home and abroad. A fermentation process was established and optimized, which, after trial production under five tons and 20 tons of liquid fermentation, enabled a shortened fermentation period by seven to eight days, A large-scale concentration and purification process based on membrane filtration and activated carbon adsorption has been established, where the fermentation broth passes through an ultrafiltration membrane and a nanofiltration membrane to remove impurities such as bacterial body and macromolecular protein, thus obtaining the concentrated solution of coronatine for use in preparation. By adding activated carbon into the concentrated solution for the purpose of adsorption and desorption, above 50% coronatine crude and above 95% pure coronatine is further obtained.

Based on the above technical achievements, in 2021, Chengdu New Sun established the world’s first coronatine fermentation line in China, which solved the problem of potency and yield of fermentation of coronatine from the source. Accordingly, the industrialized production of coronatine is realized in terms of fermentation, extraction and reduction of cost of production to the needs of mass production and promotion for scale-up application.

Significant quality and yield increase for field crops

In May 2013, after being approved by China Standardization Technical Committee, Chengdu New Sun took the lead in validating the global Chinese common name of coronatine. In terms of the end use of coronatine, Chengdu New Sun’s researchers have developed coronatine 0.006% green soluble concentrate formulation, which has reported a stable performance, having solved the problem of poor stability of biological regulators. Coronatine’s new functions have been discovered through continuous development of application scenarios, such as the enhancement of crop’s salt resistance, drought resistance, high (low) temperature resistance, disease resistance and retarding of cotton growth, promotion of defoliation and ripening. Critical technologies for field crop application have been established, which led to the readiness for coronatine’s industrialized production and field application simultaneously.

On September 3, 2021, the Institute for the Control of Agrochemicals of the Ministry of Agriculture and Rural Affairs (ICAMA) approved the registration of the coronatine 98% TC and coronatine 0.006% SL filed by Chengdu New Sun New. This meant that coronatine, the epoch-making novel plant growth regulator, is officially granted registration for the first time. So far, Chengdu New Sun has successfully launched to market its coronatine 0.006% SL.

Presently, the application of coronatine to soybean, corn, cotton, wheat and rice crops has been significantly effective in quality and yield increase. In terms of seedlings, coronatine seed coating can promote soybean germination and sound seedling under low temperatures. The results of the indoor germination experiment show that the use of coronatine 0.006% COR with seed coating agent to treat soybean can promote the germination rate of soybean seed under 50C low-temperature condition and improve the root vigor of soybean seedlings. The combined use of coronatine with a central element water-soluble fertilizer and seed coating agent in soybeans can improve the soybean’s low-temperature resistance and emergence rate. It is effective in controlling soybean root rot, and also effective to a certain extent against soybean brown streak, target disease and soybean aphid.

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Figure 2 Effect of coronatine with seed coating on germination rate of soybean

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Figure 3 Effect of coronatine with seed coating on germination rate of soybean

Under high salt stress in a cotton field, the use of coronatine 0.10.1 μmol/L can reduce the hydrogen peroxide content in cotton leaves to reduce leaf damage. Cotton seed soaked in coronatine 0.01 0.1 μmol/L for 12 hours can improve the vitality of seeds under salt stress to promote germination and seedling growth, enhancing the salt tolerance of cotton seedlings. The field trial for cotton yield increase via the use of coronatine formulation shows that the plant stem diameter, the number of cotton bolls and the weight of cotton bolls in the coronatine-treated area have all increased.

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Figure 4 Effect of coronatine on cotton saline tolerance

Coronatine can be applied to seed dressing before sowing and be sprayed at the rupturing stage and the full heading stage. The results of the rice field demonstrative trial show that the emergence in the coronatine-treated area is higher, where seedlings are thick and robust, with increased ear length at the mature stage, increased number of grains per ear and 18% yield increase. The head rice rate, amylose and protein content of rice are also improved.

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Figure 5 Effect of coronatine on rice ear length

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Figure 6 Analysis results of experiment of improving quality and increasing yield of rice by coronatine

Besides the field crops, Chengdu New Sun’s application of coronatine has played a vital role in promoting coloring, and sugar degree enhancement in favor of citrus, grape, tomato and apple, which can effectively promote the uniform coloring of fruits and increase the sugar content by 2 ° in average, whilst fruits ripen 7-10 days ahead of time. The company is currently conducting continuous in-depth research and transformative field applications concerning defoliation and weeding.

In the years ahead, the innovative applications of coronatine are bound to play an active and extensive role in improving global food security, agricultural product output and quality. They will set off a new round of scientific and technological innovation to drive the advancement of agricultural production and technical development worldwide. Chengdu New Sun is determined to play its sustained and fundamental role in solving the problems of the food crisis, food production and food security.

This article was initially published in AgroPages' 2023 China Pesticide Industry Watch magazine.