Core Viewpoint - Cotton is evolving from a traditional textile material to a multifunctional resource, capable of producing valuable compounds like astaxanthin through advanced biotechnological methods [4][12]. Group 1: Cotton's Traditional Uses - Cotton fibers are categorized into three main types: coarse short-staple cotton, fine-staple cotton, and long-staple cotton, each serving different textile applications [4]. - The majority of cotton grown in China is fine-staple cotton, which is widely used in everyday textiles and medical supplies [4]. Group 2: Innovative Applications - The development of engineered cotton capable of producing astaxanthin, a potent natural antioxidant, represents a significant advancement in cotton's utility [6][12]. - Astaxanthin is recognized for its superior antioxidant properties compared to vitamin E and β-carotene, with applications in food, feed, pharmaceuticals, and cosmetics [6]. Group 3: By-products and Sustainability - Cotton seeds are a major source of edible oil and protein for animal feed, with cottonseed meal being the second-largest source of plant protein in China [8]. - Cotton by-products, such as cottonseed hulls and short fibers, have diverse applications in food, pharmaceuticals, and biodegradable materials, enhancing the overall value of cotton production [9][10]. Group 4: Future Prospects - The integration of synthetic biology in cotton research is expected to lead to the development of new cotton varieties with enhanced functionalities and colors, reducing environmental impact from dyeing processes [12]. - The ongoing research aims to expand cotton's application across agriculture, food, health products, energy, and environmental sectors, positioning cotton as a versatile and sustainable resource [11][12].