Chitosan oligosaccharide (COS) is a low-molecular-weight biopolymer derived from the deacetylation and hydrolysis of chitin—abundantly found in the exoskeletons of crustaceans such as shrimp and crabs. Compared to regular chitosan, COS has higher water solubility, better bioavailability, and stronger biological activity, making it more suitable for agricultural applications.
In recent years, COS has gained increasing recognition as a natural plant biostimulant, plant immune inducer, and abiotic stress mitigator, contributing to sustainable and efficient crop production.
How Does Chitosan Oligosaccharide Work?
Chitosan oligosaccharide functions through multiple mechanisms at physiological, biochemical, and molecular levels:
1. Activation of Plant Immune Response
COS acts as an elicitor, triggering the plant’s innate immune system. Upon application, it induces:
-
Systemic acquired resistance (SAR)
-
Production of pathogenesis-related proteins (PR proteins)
-
Accumulation of defense-related enzymes (e.g., peroxidase, polyphenol oxidase)
-
Enhanced synthesis of phytoalexins and callose
These mechanisms improve the plant’s resistance to a broad range of fungal, bacterial, and viral pathogens.
2. Promotion of Nutrient Uptake and Root Growth
COS stimulates root elongation and branching, enhancing:
-
Nutrient and water absorption
-
Rhizosphere microbial activity
-
Root-to-shoot nutrient transport
This directly supports stronger plant establishment and better resilience during early growth stages.
3. Regulation of Hormone and Gene Expression
Chitosan oligosaccharide has been shown to:
-
Stimulate the biosynthesis of auxins, gibberellins, and cytokinins
-
Upregulate expression of growth-promoting and defense-related genes
-
Promote chlorophyll content and photosynthetic efficiency
4. Anti-Stress and Anti-Oxidant Effects
COS enhances tolerance to environmental stresses such as:
-
Drought
-
Salinity
-
High and low temperature
-
Heavy metal contamination
It also increases antioxidant enzyme activity (SOD, CAT, POD), reducing oxidative damage under stress.
Agricultural Applications of Chitosan Oligosaccharide
Chitosan oligosaccharide can be applied in various forms across multiple crop types. Common use cases include:
1. Seed Treatment
-
Improves germination rate and seedling vigor
-
Enhances early root development
-
Protects against seed-borne diseases
2. Foliar Spray
-
Boosts photosynthesis and vegetative growth
-
Induces resistance against leaf diseases (e.g., powdery mildew, bacterial spot)
-
Enhances flowering and fruit setting
3. Soil Application / Fertigation
-
Improves soil microbial diversity
-
Synergizes with fertilizers, improving nitrogen use efficiency
-
Enhances root zone resilience under stress
4. Combination with Fertilizers and Pesticides
-
Enhances uptake and effectiveness of nutrients and agrochemicals
-
Reduces pesticide usage by improving plant defenses
-
Compatible with organic or conventional programs
5. Post-Harvest Treatment
-
Reduces spoilage in fruits and vegetables
-
Prevents microbial decay during storage
-
Extends shelf life without chemical residues
Key Advantages of Using COS in Agriculture
| Feature | Benefit |
|---|---|
| Natural & Biodegradable | Safe for the environment and non-toxic to humans, animals, and beneficial insects |
| Broad-spectrum Resistance | Effective against fungi (Fusarium, Botrytis), bacteria (Pseudomonas, Xanthomonas), and viruses |
| Stress Tolerance | Helps crops maintain yield and quality under abiotic stress conditions |
| Improved Yield & Quality | Promotes uniform growth, better fruit set, and enhanced crop appearance |
| Residue-free Crop Protection | Ideal for organic and export-focused agriculture |
Suitable Crops
Chitosan oligosaccharide is suitable for a wide range of crops, including:
-
Vegetables: tomato, pepper, cucumber, leafy greens
-
Fruits: grape, citrus, strawberry, apple, banana
-
Field Crops: corn, wheat, rice, soybean, cotton
-
Ornamentals: flowers, nursery plants, turf
-
Specialty Crops: tea, coffee, medicinal plants
Market Trends and Future Potential
With growing global demand for sustainable and eco-friendly agriculture, the use of bio-based inputs like COS is expanding rapidly. Regulatory frameworks in many countries are encouraging reduced chemical pesticide use and improved soil health.
Chitosan oligosaccharide meets all these trends, offering a natural solution aligned with integrated pest management (IPM), regenerative farming, and organic certification standards.
Chitosan oligosaccharide represents a new generation of agricultural biostimulants that support healthier crops, higher yields, and sustainable practices. With its multiple physiological effects, natural origin, and environmental safety, COS is an ideal choice for modern agriculture.
