Lignin in fruits: Structure, function, and frontier perspectives on biosynthesis and regulation

As a key component of secondary cell walls, lignin is irreplaceable for fruit growth: it provides mechanical support for normal fruit morphology and growth, enhances stress resistance to reduce external interference, and maintains post-harvest quality, directly affecting commercial value and shelf life. Given lignin's importance, exploring its structural characteristics, functional mechanisms, biosynthetic pathways and regulatory rules is key to revealing fruit growth essence and post-harvest quality change mechanisms. This supports fruit quality improvement and storage extension, guides new product development and optimization of cultivation/processing technologies, and promotes sustainable and efficient fruit industry development. This review adopts a systematic literature review to study fruit lignin: it retrieves and screens relevant studies from plant science, food science, horticulture databases (covering multiple fruits and research directions), then organizes, classifies and analyzes the data to expound lignin's key properties, functions, biosynthesis and regulation, and prospects future research, aiming to provide systematic theoretical support for subsequent fruit research and industrial practice.