The Genetic Transformation Mechanism and Application of Plant Hairy Roots

Innovation in plant-breeding technology relies on precise, targeted genetic manipulation, which depends on the efficient delivery of genetic elements and robust plant cell regeneration systems. Agrobacterium tumefaciens, a traditional medium for genetic material delivery, is well established and has become widely adopted, but it faces limitations such as species specificity, transformation chimerism, and the requirement for two-step processes of transformation and regeneration. In contrast, Rhizobium rhizogenes can deliver genetic material with efficiency comparable to that of A. tumefaciens while excelling in producing transgenic homozygotes in a single step. This article summarizes the molecular mechanisms underlying R. rhizogenes-mediated hairy-root induction in plants, discusses the development of genetic material delivery systems, details the construction of hairy-root induction and regeneration platforms, explores molecular mechanisms in hairy roots and their applications in genetic breeding, and highlights the use of hairy roots for extracting secondary metabolites. The hairy-root genetic transformation system provides efficient, simplified, and broadly adaptable tools for genetic manipulation in breeding, accelerating the advancement of cutting-edge technologies such as gene editing, rapid domestication, and synthetic biology-driven breeding.