Flavonoid pathway in cotton fiber development

Cotton fiber is the most important natural fiber. Development of colorful cotton varieties with super quality has always been an important goal of cotton genetics and breeding research. Flavonoids that are associated with the formation of pigment are important plant secondary metabolites. In this review, we describe the advances of flavonoid pathway in cotton fiber: brown pigments in cotton fiber may mainly belong to proanthocyanidins. The flavonoid pathway is down-regulated in white cotton with domestication process, but in white cotton, gene expression profiling data show that genes involved in flavonoid pathway are still very active in fiber development. It was generally believed that flavonoids negatively correlated with fiber quality, naringenin and dihydrokaempferol may inhibit the development of fiber. Flavonoid metabolism and lignin metabolism have common metabolic precursors and genes involved in lignin metabolism are also very active in fiber development, and effective regulation of the metabolism of flavonoids, meanwhile coordinating lignin metabolism, may contribute to fiber development.