Abstract:
Tropical recalcitrant plants refer to tropical plants that exhibit significant resistance to in vitro culture and genetic transformation, with their breeding improvement being limited by low regeneration efficiency and strong genotype dependence. In recent years, the coordinated development of CRISPR/Cas-based genome editing and diversified genetic transformation systems has opened up a new way to break through this bottleneck. In this article, the physiological characteristics and biological basis of regeneration obstacles in tropical recalcitrant plants were systematically reviewed, and the internal mechanisms such as the restricted expression of cell totipotency, the activation of defense responses, and the imbalance of molecular regulatory networks, were deeply analyzed. The latest progress of two key transformation strategies, tissue culture-dependent and in situ transformation systems without tissue culture, was reviewed emphatically. Meanwhile, the evolution trend of gene editing delivery systems was summarized. Finally, the development prospects of molecular breeding of tropical recalcitrant plants was propected, and it was proposed that future research should be based on the species-specific biological laws, adopt targeted technical strategies, and pay attention to the collaborative application of various technical routes.