Unlocking the molecular secrets of Paeonia plants: advances in key gene mining and molecular breeding technology

Paeonia plants are famous for their ornamental, medicinal, and oil values. Due to the popularity of seed oil and cut flowers in the market, the mechanisms underlying related traits of Paeonia plants have been fascinating, and the research work on them has increased rapidly in recent years, urging a comprehensive review of their research progress. To unlock the molecular secrets of Paeonia plants, we first summarize the latest advances in their genome research. More importantly, we emphasize the key genes involved in plant growth and development processes, such as bud dormancy, flowering regulation, seed oil formation, flower coloration, stem strength regulation, fragrance emission, as well as plant resistance to stress, including drought, high-temperature, low-temperature, salt, and waterlogging stresses, and biotic stress. In addition, the advances in molecular breeding technology of Paeonia plants are highlighted, such as molecular marker, genetic map, localization of quantitative trait loci, tissue culture, and genetic transformation system. This review covers advances in the past decades and provides valuable insights into the perspectives for the key gene mining and molecular breeding technology of Paeonia plants, which would help breed new Paeonia varieties through molecular breeding technology.